Temperatures along the I-95 corridor are set to drop into the upper 20s and low 30s Friday night into Saturday morning. The National Weather Service has posted freeze warnings from 1 a.m. to 8 a.m. Saturday for Baltimore, Washington and all counties along the Chesapeake from Harford in the north to St. Mary's in the south.

The hard freeze will finally bring the 2009 growing season to a halt in the area, and kill off any tender plants that are still outdoors tonight.

The forecast low for BWI-Marshall Airport - and for much of the surrounding region tonight, is 29 degrees, which would be the lowest reading there since April 13, when the low was also 29. Downtown, the low is likely to be slightly higher, around 33 degrees.

The cold night is brought to us courtesy of high pressure that's been building in from the Ohio Valley. That's bringing clear skies and, as it moves closer tonight, calming winds. And that is the recipe for radiational cooling tonight, which will bleed away much of the solar heating we're able to store up today, and drop temperatures.

The weekend and the early part of next week look like they'll remain mostly sunny during the day, and clear at night. Daytime highs should poke back into the 60s by Sunday.

Then there's this from the NWS:

"HIGH PRESSURE BUILDS BACK IN OVER THE REGION FOR THE END OF
NEXT WEEK. THIS HIGH CENTER SHOULD KEEP ANY MOISTURE ASSOCIATED WITH
ANY REMNANTS OF [tropical storm] IDA WELL SOUTH OF THE CWFA [forecast area] NEXT WEEK."

Posted by Frank Roylance at 10:18 AM | Permalink | Comments (1)
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Clear skies and calming winds could combine to produce a hard freeze tonight in portions of the state west of the urban corridor. The National Weather Service forecast office in Sterling, Va. hasn't posted any frost or freeze warnings yet (except in Cecil County and on the upper Eastern Shore), but there is a "Hazardous Weather Outlook" noting that:

"TEMPERATURES WILL DROP TO THE MID 30S LATE TONIGHT WEST OF
INTERSTATE 95...WHICH MAY PRODUCE A KILLING FROST."

UPDATE: The NWS this afternoon issued a frost advisory for all counties north and west of Baltimore, including northern Baltimore, Carroll, Howard, Frederick, Montgomery and Washington counties:

"CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPERATURES TO DROP INTO THE
LOWER AND MIDDLE 30S ACROSS THE WESTERN SUBURBS OF WASHINGTON DC AND
BALTIMORE...THE CENTRAL VIRGINIA FOOTHILLS AND PORTIONS OF THE
EASTERN PANHANDLE OF WEST VIRGINIA. AS A RESULT...AREAS OF FROST
ARE EXPECTED TO DEVELOP OVERNIGHT AND EARLY WEDNESDAY MORNING.

"PRECAUTIONARY/PREPAREDNESS ACTIONS...

"A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR
PLANTS MAY BE KILLED IF LEFT UNCOVERED."

The forecast low for BWI tonight is 37 degrees, but that drops off quickly to 33 degrees in Westminster, 32 in Shrewsbury, Pa., and in Poolesville, Md.

Thursday night may be even colder, with a low of 35 at BWI, and below freezing well west of the city. There are snow showers in the forecast for Garrett County late Wednesday and Thursday.  

NOTE TO READERS: The barrel's empty. Be famous for a day. Send in your weather or backyard astronomy questions and see them answered on the Page 2 print weather page. Or is it Page 3 now?  Thanks! - FDR 

Posted by Frank Roylance at 11:42 AM | Permalink | Comments (0)
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Sunshine and clear skies continue to grace Maryland counties to the west of the I-95 corridor. But somehow the clouds have lingered stubbornly over the urban corridor, despite all that hope we lavished on the situation Sunday.

Forecasters out at Sterling say the problem has been the slow-moving low off the Carolinas, which has kept the clouds clinging to the coastline. The problem now becomes whether that coastal storm will drift azway, and clear our skies, before the next weather disturbance moves in with a weak cold fron on Tuesday.

"Did an update to try to better depict the cloudy versus clear area. At the rate the cloud cover seems to be waning, another may be needed shortly to paint a more optimistic picture," the weather folks said in their Monday morning discussion.

The good news is that none of the forecasts include more rain for our area, although some places in the mountains could see some showers Tuesday morning, and maybe some snow showers by Thursday morning as temperatures there sink into the 20s. Our week looks generally sunny after today, with highs at BWI in the 50s to near 60 degrees.

The weather news headline for us - aside from those promises of sunshine - may be the Tuesday-into-Wednesday-morning forecast for lows near the freezing mark. That would be the coldest reading of the season so far, and could put an end to the growing season for the northern and western Baltimore suburbs. The city low forecast for Wednesday morning is around 40 degrees.

Finally, the full Hunter's Moon (or, if you prefer, the Frosty Moon or the Beaver Moon) rises over Baltimore tonight beginning at 4:41 p.m. EST. With any luck, the clouds will be gone.

Posted by Frank Roylance at 10:49 AM | Permalink | Comments (0)
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Don't despair, Baltimore. The weather gods have been taking their time, but the cold front is moving off, and the cloud deck over our heads is about to pass off to the south and east of the city.

So the sun should be coming out shortly. Here (left) is the satellite view of the region, taken around noon Sunday.

You can see the clear skies out to our west. And here's the Northeast radar loop.

Forecasters say the week ahead looks cool, but sunny. 

Hagerstown is already under fair skies.

Hang in there.

Posted by Frank Roylance at 12:56 PM | Permalink | Comments (0)
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Forecasters out at Sterling are calling it a "hybrid damming situation," but for those of us here in Central Maryland it just looks like a long, chilly wait for sunshine to return.

Here's the deal:  There is a high-pressure system centered over Maine at the moment. Highs spin clockwise, so it's sending cool, moist air our way off the Atlantic. There is also a low-pressure system far off the Delmarva coast. Lows spin counterclockwise. So that one is reinforcing the flow off the ocean. That's the "hybrid" part - high and low combining to produce the breeze off the ocean.

So all that cool, moist air is flowing onshore, out of the east, and then running into the eastern slope of the Appalachians. That's the "damming" part. The cool, wet air gets stuck here near the surface, even though the air mass above it is relatively dry. And we're underneath it all, in chilly air, looking up at overcast skies, and occasionally getting drizzle in the face.

When we get cold air damming in winter, that can set us up for a pile of snow if a storm develops to our south and rolls up the coast. But not yet.

The rub this time is that, even as weather systems shift around a bit in the next few days, NWS forecasters say we'll see little but gray clouds, and some drizzle on Friday morning. The drizzle will fade by noon, they say, and we may see some sunshine Saturday afternoon, and highs as toasty as 72 degrees. That will be a nice break for Trick or Treaters, like the weirdos at left.

But that's all in advance of another cold front sometime late on Saturday. And that will bring more clouds and showers overnight until the front passes.

Sunday may start out with showers, but things should clear off later, winding up mostly sunny and cool if the forecast holds up, with a high near 60. That'll be your day to get outside.

November looks like it will start out sunny and dry.

Posted by Frank Roylance at 11:21 AM | Permalink | Comments (5)
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As if we haven't had enough already (another inch fell on Friday and Saturday), the National Weather Service has still more rain in store for us this week.

We'll get a few more sunny days toward the end of the week, but we're going to have to chalk this month up as seriously soggy. The bulk of that rain fell during those five days of water torture two weeks ago.

In fact, Baltimore has been running a fat rain surplus since April rains ended a very dry fall and winter. We're 11 inches on the plus side since April 1, with more to come this month.

This afternoon's forecast is calling for a chance of rain Tuesday as this coastal low begins to affect the region overnight Monday into Tuesday with some early morning drizzle and rain. (Hard to accept, given how pretty it is out there this Monday afternoon.)

That rain will ease off in the afternoon Tuesday as the coastal low moves off. Then we'll get a break until another low moves in from the southwest late Tuesday into Wednesday. This one is much wetter. 

Today's forecast discussion calls for an inch or more of rain from this second wave. But then a high-pressure system to our north will move in after the rain and dry things out, with sunny days due for Thursday and Friday.

Halloween could bring some more daytime rain the next cold front moves through. With luck things will simmer down for the evening's festivities. The low will approach 50 degrees.

The airport has already clocked 4.31 inches of rain this month (graph at right). That's 1.74 inches more than the long-term average for the month to date in Baltimore. Another inch Tuesday and Wednesday would only make a wet month wetter.

(SUN PHOTO/Frank Roylance; graphic by NOAA)

Posted by Frank Roylance at 4:18 PM | Permalink | Comments (2)
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The feature that dominate the weather map today is that big low-pressure system moving out of Missouri and headed north and east into the Great Lakes and Quebec on Saturday.

For now, we're getting into an easterly wind off the ocean, driven by the clockwise flow around a high moving over New England. That means increasing cloud cover, maybe a little rain late this afternoon and evening, and temperatures that won't move much from the mid-60s, where they are now.

But as the Midwestern low moves along, it will drag a cold front across the region on Saturday, and draw more moisture in off the ocean to the southeast. And that's what will produce most of the rain that's headed our way on Saturday. There may even be some thunder. By the time it's all over, we could have a half-inch, to as much as an inch of rain from all this.

Here's AccuWeather.com's take on the rain.

The good news in the morning discussion out of Sterling seems to be that the rain associated with the frontal passage will be relatively brief. We won;t be stuck with it for days on end like we were last week.

Skies should dry out quickly, with sunny skies in the wings for Sunday. If you're eager to get out in the woods or onto the bike trails to enjoy the fall colors, plan it for Sunday - or Monday if you've got the day off.

Posted by Frank Roylance at 10:28 AM | Permalink | Comments (0)
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Wednesday's high of 75 degrees at BWI made for a delightful day if you could get out to enjoy it (I finally did). It wasn't close to a record, which would be the 90-degree reading for Baltimore on Oct. 21, 1947.  It was, however, 30 degrees warmer than it was on Friday of last week. So it sure felt like heat to many of us.

Thursday's record high is only 85 degrees (set in 1979). But as nice as it will be today, we won't get nearly that high, either. Forecasters out at Sterling are calling for a high of 74 degrees at BWI-Marshall, with clouds beginning to encroach on the area as that cold front approaches from the Midwest.

And that will end this pleasant stretch, sending temperatures back toward normal highs, which at this end of October are around 65 degrees. Friday's forecast high is just 63 degrees, with showers developing late in the day.

That rain will likely get heavier overnight and into Saturday, with as much as an inch possible before the lows moving along the cold front depart and it tapers off. 

At least this next batch of rain won't linger long. By Sunday we should be back in the sunshine, but with highs 10 degrees cooler than we're seeing this week - and close to the normal range for this time of year. The next frontal system and rain chances move in after mid-week.

(Graphic: National Weather Service)

Posted by Frank Roylance at 10:18 AM | Permalink | Comments (0)
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Blue skies, warm sunshine and highs in the 70s over the Maryland Penitentiary today - which is about all I will likely see of this absolutely perfect October weather, stuck in the newsroom as I am. 

(Not as stuck, fortunately, as the folks in the Pen, under the tin roofs in the background of the photo below. The yellow-brick building is Catholic Charities' Employment Center in this view from the newsroom window. The Sun's weather station is on the pole in the bottom center of the photo. Our ginkgo trees are still a couple of weeks away from their golden autumn glory.)

If you can get outside today (and tomorrow), do it. (Some of us may even see temperatures touch 80 degrees in spots.) Because by Friday we will be under the influence of an approaching cold front.

Light rain is expected to move in after noon Friday as storms track from the Midwest into the Great Lakes. That will draw moisture in here with a warm front, just ahead of a cold front and what could be a "soaking rain" on Saturday, forecasters said.

Once the front passes later on Saturday, rain may linger a bit. But the sun will return by Sunday and we should have sunny skies and highs in the 60s going into the new week.

If you were out watching for Orionid meteors this morning, drop us a comment and let us know what you saw. Some observers are reporting rates up to 35 meteors per hour. If you slept in, and regret it, skies should remain mostly clear tonight, so you'll get another chance. Here's a gallery of 2009 Orionid meteors. 

Once again, find a spot with dark skies and a clear view in all directions. Counts will be declining for the rest of the week, but the meteor-watching should still be worthwhile. Best time to look? In the hours before dawn.

Posted by Frank Roylance at 11:13 AM | Permalink | Comments (0)
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No, not the second Flood, or the End of the World. The end is near for this five-day stretch of unseasonably cold and very wet weather.

The National Weather Service is forecasting sunshine for Monday - and nearly the entire week (through Thursday) - with high temperatures climbing in to the 60s, to near 70 by Thursday. The deep low-pressure system that has brought us the latest of the cold and rain is now off Delmarva, and will soon be moving off to sea. The rain is moving into New England. That will allow high pressure to build in (the barometer is already rising) and bring us nicer, more seasonable, weather.

But it's been a long time coming. And we still face a 90-percent chance of more rain today, and a high, again, in the 40s.

As we've noted before, we expect today will mark the fourth consecutive day with highs below 50 degrees. If so, it will be the first time that's ever (since record-keeping began in 1871) occurred in October in Baltimore.  It will also be only the second time on record (the last was in 1899) that we have set (or tied) all-time record-low maximum temperatures for five consecutive days.

UPDATE: Nope. The airport high today was 52 degrees. So we had only three straight days in the 40s (not four as I stated incorrectly earlier; we touched 50 on Wednesday). That ties the record. Today's high also exceeded the record-low maximum for the 18th of October by one degree. So we had only four straight days of tied or broken record low-maximums - one fewer than the record of five set in 1899. Here are the four new record-low maximums, and today's:

Oct. 14: 50 degrees (tied), 2009

Oct. 15: 43 degrees, 2009

Oct. 16: 48 degrees, 2009

Oct. 17: 45 degrees, 2009

Oct. 18: 51 degrees, 1972 (today 52 degrees)

Earlier post resumes...

Amazing. And that doesn't even touch the snow that readers have been reporting just over the line in Pennsylvania. I suspect we'll hear from others west of the city before long. Here are some Maryland snow totals from the NWS.

We've clocked an inch of rain since midnight Sunday morning here on the WeatherDeck in Cockeysville. The total since the rainy weather began on Wednesday (as of 8:30 Sunday morning) is 3.7 inches. That's about a month's worth of rain in five days. The total for the month so far is 3.86 inches.

At BWI, the NWS has recorded 3.18 inches since Wednesday. Here are some more totals from around the region for the 24 hours ending at midnight Saturday night.

At The Baltimore Sun station, Calvert & Centre streets, the instruments have recorded 2.6 inches of rain since Wednesday.

Some other readings since midnight Sunday morning:

Bishopville, Worcester County:  2.91 inches

Ellicott City, Howard County:  1.92 inches

Columbia, Howard County: 1.77 inches

Eldersburg, Carroll County: 1.67 inches

Severn, Anne Arundel County: 1.43 inches

Jarrettsville, Harford County:  1.26 inches

(SUN PHOTOS/Frank Roylance)

Posted by Frank Roylance at 8:19 AM | Permalink | Comments (5)
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The full range of temperatures here at The Sun from Thurday afternoon to Friday morning was a measly 6 degrees - from a high of 47 to a low this morning of 41. It was colder out on the WeatherDeck this morning, and out at BWI, too, where we dipped to 40 degrees and tied the coldest reading for the season so far.

The prospects aren't any better. Forecasters out at Sterling expect daytimes highs will be stuck in the 40s through Sunday. And that, as we've noted, will set a new record of four straight days in October below 50 degrees. We've had three straight October days in the 40s before, but never four since record-keeping began in 1871.

Official forecast highs for the airport:  45, 44 and 46 degrees, for Friday through Sunday.

And, there are more records set to fall, says Steve Zubrick, science and operations officer for the NWS forecast office in Sterling:

"Also, today (Thursday), broke  the record low maximum of 50 set in 1876 ! And, if we actually get three more days of sub-50 Fahrenheit ... those will all be new record low maxima. Yesterday's (Wednesday's) high of 50 degrees F at BWI tied the record low max ... Impressive early-season cold."

And wait! There's more...

"If our forecast holds...that would make  5 days of record LO-MAX readings. I'll have to look that up...and I did. The longest number of consecutive days in a given year of setting the record LO-MAX happens to be 5 in a row...back from Feb. 9-13, 1899. What a cold snap that was! (Daily high temperature) readings were 8 / 3 / 11/ 11/ 10 during that spell...and the reading of 3-above on the 10th of Feb. is the all-time lowest LO-MAX reading for Baltimore for not only the month (Feb) but for the entire year."

Then there's the drizzle. The dripping that began on Wednesday has added up to just two-thirds of an inch here at The Sun. Ditto for BWI. But it has made for plenty of headaches on the morning and afternoon commutes. Not sure why that is. I know rain flummoxes drivers in Los Angeles, but I thought it took a "wintry mix" to do that to Marylanders.

Speaking of wintry mixes, forecasters are still noting the possibility of rain AND snow for Saturday night in suburbs west and north of Baltimore and Washington, including Westminster. Hagerstown and points west could see snow mix in by tonight. Garrett County is looking at some accumulating snow today and through the weekend.

State College, PA. recorded its earliest measurable snowfall, with 0.3 inch on the ground Thursday.

And then there are the high tides. The lingering low pressure off the coast is drawing more water up into the Chesapeake Bay, and easterly winds are throwing it up against the Western Shore. Coastal Flood Advisories are posted for the region.

Add to that the new moon on Sunday and we have water lapping up over the shoreline. Eric Bates checked in from Quinby, Va., this morning, with a photo of the flooding along the piers there. Anyone else have any Maryland high-tide photos this morning?

Continue reading "Ireland on the Patapsco; cold drizzle continues" »

Posted by Frank Roylance at 10:39 AM | Permalink | Comments (5)
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The average high temperature in Baltimore at this time of year is 68 degrees. But we'll be dressing for temperatures about 20 degrees colder than that by Thursday morning, according to the National Weather Service forecast office in Sterling. Add in rain - and overnight snow at higher elevations to our west - and we're looking at a nasty package for Marylanders as we head into the weekend.

The forecast out for Baltimore this morning calls for rain developing tonight and tomorrow as low-pressure systems converge on the region from the Tennessee and Ohio Valleys, and along the East Coast. The rain chances rise to 100 percent on Thursday, with forecast highs of just 47 degrees at BWI. As much as an inch of precipitation is possible at the airport.

The rain will continue Thursday night, with another half to three-quarters of an inch added in. Temperatures will remain in the 40s through Saturday, with better-than-even chances of rain continuing.

Saturday night's lows will drop into the 30s if the forecast holds up, with rain chances continuing into Sunday. Western Maryland will be stuck in the 30s, and at the higher elevations, there is a risk of snow, although no significant accumulations are expected.

(Actually, there were plenty of readings in the 30s in the area this morning. It was 38 on the WeatherDeck in Cockeysville.)

So let's see... stormy weather moving into California, crossing the continent and regenerating in the South, then moving up the East Coast ... That sounds a whole lot like the El Nino Winter scenario. If it persists, a setup like this in, say, a cold spell in January or February, could deliver a pretty significant snowstorm to Maryland. 

But, I digress. As this coastal low moves off into the Atlantic, we'll still be stuck with a chance of light rain until Monday, when high pressure begins to move in, finally, with sunshine pushing daytime temperatures into the low 60s again. Still cool for this time of year, but it will be a welcome relief.

(SUN PHOTO/Amy Davis/Baltimore 2005)

Posted by Frank Roylance at 10:49 AM | Permalink | Comments (3)
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It looks like the first forecast this fall with the words "rain/snow mix" and "winter precipitation" in it. Seems way too early, but there it is.

The forecast discussion for Central Maryland, posted this morning by the National Weather Service forecast office out at Sterling, is predicting lows in the mid- to upper-30s Thursday and Friday nights for the higher elevations of the Blue Ridge mountains to our west. By Friday night into Saturday morning, there will be enough moisture and low-enough temperatures out there to produce a snow/rain mix at high elevations.

Down here in the lowlands, we're looking at a low close to 40 degrees by Saturday morning, with up to a quarter-inch of rain as storm systems approach from the Ohio Valley late this week, and a Georgia low moves up the coast.

In the meantime, the weather service has posted frost advisories for Washington and Allegany counties tonight, including the cities of Hagerstown, Frostburg and Cumberland, where lows are expected to dip into the 30s. There are freeze warnings up for Garrett County.

The cold weather comes to us courtesy of a slow-moving high-pressure system that is settling over the Great Lakes. The clockwise flow around the high will be drawing cold, dry air our way on north winds out of Canada. Friday's forecast high for Baltimore is only 49 degrees. If that holds up, it would be the first time since April 15 we've failed to break 50 degrees.

It was 42 degrees this morning out on the WeatherDeck in Cockeysville. The house was 68, which was enough to drive us to plug in the electric blanket. But the furnace remains silent. It's our goal to keep it that way until Nov. 1. You?  

The good news is that the US Dept. of Energy is forecasting lower prices this winter for fuel oil and natural gas. AccuWeather.com reports that the cost of heating homes nationally will be 8 percent lower this season. It's down 12 to 14 percent for natural gas and propane.

(SUN PHOTO/Doug Kapustin/McHenry, Md., October 2005)

Posted by Frank Roylance at 10:45 AM | Permalink | Comments (6)
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It looks like Tuesday will be the day to beat this week. Today, we'll be stuck under this overcast for most of the day, with temperatures likely to struggle to to get out of the 50s. That's as much as 10 degrees below the long-term averages for Baltimore at this time of year.

But as a cold front slips by early Tuesday, we'll get some gusty northwest winds. Skies will clear off, the sun will shine and temperatures will climb toward 70 degrees - the high point of the week.

Then, as the high pressure system moves off the coast, the forecast takes a downhill turn. A storm system over the central plains will move our way, increasing rain chances on Wednesday. We'll be stuck in the low- to mid-50s from Wednesday through Friday as a coastal low forms to sustain our cool, rainy forecast into the weekend.

Things should begin to clear off on Saturday, with Sunday the best bet for the weekend, if the forecast holds. Look for sunny skies on Sunday, with a high near 60 degrees.

(BALTIMORE SUN PHOTO/Amy Davis October 2002)

Posted by Frank Roylance at 10:55 AM | Permalink | Comments (2)
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As gorgeous as this Friday has been in Baltimore, you knew it couldn't last. Sure enough, there's a pretty impressive (on the radar) cold front approaching from the north and west, and forecasters insist we're in for some rain Friday night or early Saturday.

That may seem hard to believe given the beautiful sunshine and 80-plus temperatures we've enjoyed today. Our high here at Calvert and Centre streets was 84 degrees. The airport measured at least 83 degrees at last check. Nowhere near a record. It was 94 degrees here on this date just two years ago.

But that cold front will press through here after midnight tonight, and we can expect showers into the morning hours. We're already feeling the effects of the approaching front, with strong southerly winds during the day today.

Temperatures behind the front will be 10 to 15 degrees cooler than we've seen today, with highs Saturday only near 70 degrees. Skies will clear off slowly, with partly sunny but even cooler weather for the rest of the holiday (for some of us) weekend. Enjoy.

Posted by Frank Roylance at 5:32 PM | Permalink | Comments (0)
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It's going to be a beautiful day today (Wednesday), but you'll need to hang onto your hat. As the cold front moves off over the Atlantic, and high pressure builds across the region, the winds will pick up today out of the northwest and west.

The National Weather Serevice has issued a wind advisory for all of Central Maryland through 6 p.m. Wednesday. Wind speeds will rise to between 20 and 30 mph later this morning, with gusts between 40 and 50 mph before they diminish around sunset. There are gale warnings on the Bay until 4 p.m.

That sort of wind can cause minor property damage, and make driving high-profile vehicles a wrestling match. 

UPDATE: More than 32,000 BGE customers lost power Wednesday as high winds knocked down electric lines.   

We're seeing increased winds here at The Sun, - gusts as high as 19 mph so far - but our anemometer is pretty sheltered by trees and buildings.

BWI-Marshall has already clocked gusts to 24 mph.

Got your own weather station? Let us know what kinds of gusts you're seeing today. And if you snap any nice autumn-y photos of blowing leaves, send 'em in.

UPDATE: Winds seem to have peaked at BWI with gusts to 49 mph. Our highest at Calvert and Centre streets was 26 mph.

These winds will be dry. Relative humidities - now in the mid-50 percent range in Baltimore - will be falling to 30 or 35 percent. Coupled with the winds, that will raise the fire hazard. The NWS has issued a Special Weather Statement this morning noting the "enhanced fire threat." Although fuel on the ground is somewhat damp, forecasters say drying conditions could reach a point later today where they will need to issue Red Flag Warnings across the region.

UPDATE: Lowest relative humidity here at The Sun was 41 pct.

Whatever, be careful with open fires today and crush those butts.

Once the winds die down, we're looking at beautiful weather across the region tonight and tomorrow, with a forecast high Thursday of 70 degrees. Friday will bring increased clouds, with another cold front due later in the day. That will bring another chance for some showers. The weekend looks sunny but cooler, in the mid- to upper-60s. Yet another cold front on Columbus Day will drop daytime highs to near 60 degrees, with overnight lows in the 40s.

Posted by Frank Roylance at 10:41 AM | Permalink | Comments (0)
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The barometer has already headed south as a cold front approaches , pushing a fast-moving band of showers out ahead of it. They should reach us late tonight. That will set us up for a breezy day on Wednesday, with the dry, northwest winds likely to dry out the underbrush and raise the danger of wildfires.

But by late Wednesday, skies will start to clear as high pressure builds, dropping overnight lows into the 40s in central Maryland. Sunshine will boost daytime temperatures back into the 70s by Friday, but another cold front late Friday will bring more showers and a significant drop in temperatures as skies clear for the weekend.

There's yet another cold front due on Monday, Columbus Day, and by early next week we will be hard-pressed to get the thermometer past 60 degrees - almost 10 degrees below the seasonal norms.

Overnight lows will sink into the low 40s for another real taste of autumn ... and a test of our willingness to keep the furnace off a while longer.

(SUN PHOTO/Karl Merton Ferron 2006)

Posted by Frank Roylance at 3:37 PM | Permalink | Comments (0)
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Pretty sure this is the first mention of frost in the NWS forecasts for Maryland this season. They've issued a frost advisory for the high country out in Allegany County, including the cities of Frostburg and Cumberland, where overnight lows are headed for the 30s.

We won't see anything like that down here in the lowlands. But after a patch of showers passes by later today, we should see some rapid clearing as high pressure moves into the area. The clear skies and diminishing winds open us up for some radiational cooling tonight. And that will send our overnight temperatures into the 40s, for what will likely be the coldest night of the season so far. 

So by Thursday morning it will really feel like October.

It's good news for stargazers, of course. Clear, cool, still skies are great for looking out at the universe. The moon has now moved past Jupiter, but the big planet is still big and bright in the southeast in the evening. With a good pair of binoculars, you should be able to make out as many as four of the Galilean moons, lined up in a row on either side of the planet's disk.

If you're up before dawn Thursday, look due east for a view of bright Venus low on the horizon. This is also a good time to catch a glimpse of elusive Mercury, rising just below (and just after) Venus. Mercury is followed by Saturn a short while later, but the brightening dawn will likely begin to fade the show. For a sky map, click here, and scroll down to "This Week's Planet Roundup."

Mercury, as you may have read, was visited Tuesday evening by NASA's Messenger spacecraft, which flew within 142 miles of the tiny planet just before 6 p.m. Scientists at the Johns Hopkins University Applied Physics Lab have been downloading science data from the flyby this morning. Messenger is due to enter orbit around the planet in March 2011.   

Posted by Frank Roylance at 10:07 AM | Permalink | Comments (0)
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Maybe this would be a good day to visit the book festival in Mt. Vernon and stock up. We should have sunshine today. But forecasters out at Sterling have posted a pretty gloomy set of predictions for the next few days, with on-and-off rain - some of it heavy at times - in the cards for Central Maryland. So it just seems like a good weekend to buy early and curl up with a good book.

The problem is a stalled cold front - the one that dropped down across the region overnight, bringing us a little light rain and cutting off the 80-plus temperatures and high humidity we've experienced in recent days. What we're left with are cool-to-mild temperatures that may not get much past 70 degrees today (Friday), and may not exit the 60s on Saturday - a few degrees colder than the long-term averages for this time of year.

And rain. Low-pressure systems tracking along the cold front from the Ohio Valley will be responsible for the rain that's forecast to pick up late Saturday. That rain could get heavy at times, with 1 to 2 inches possible overnight into Sunday. Maybe that will bring the month's rainfall - just 2 inches at BWI-Marshall so far - more into line with long-term averages.

Another cold front early next week will likely bring more showers before we break out into the sunshine again by Tuesday. But it will feel more like October, with highs only in the upper 60s.

(PHOTO: Baltimore Office of Promotions and the Arts)

Posted by Frank Roylance at 10:47 AM | Permalink | Comments (0)
Categories: Forecasts
        

There's more sunshine out there today (Wednesday) than forecasters expected, and plenty of humidity. That's making it feel more like late summer than early autumn. Highs this afternoon and tomorrow could reach the low to mid-80s, about 8 degrees above the norms for this time of year in Baltimore. But time is running out.

Forecasters out at Sterling say this southerly flow of warm, humid air will be cut off by an approaching cold front , now over the Great Lakes, that's expected to cross the region late on Thursday. As that front gets close, it could bring us widely scattered showers later on Thursday. But it will also bring a wind shift that should begin to clear the air and dry us out for Friday and Saturday.

It should also cool us off. Friday will be sunny and pleasant, they say, with highs near seasonal norms, in the low 70s. Saturday will be even cooler, perhaps stalling out in the upper 60s under partly sunny skies. A breath of autumn.

The next round of rainy weather could show up as early as late Saturday and Sunday, clearing as the workweek begins.

Speaking of rain, I notice that the Drought Monitor map last week once again included some "abnormally dry" conditions in far western Maryland - about 13 percent of the state. It's the first time since mid-August that Maryland has shown up on the drought map.  

The dry patch is part of a larger expanse of scarce rainfall that includes southwestern Pennsylvania, northern West Virginia and eastern Ohio.

(SUN PHOTO/Amy Davis 2004)

Posted by Frank Roylance at 11:01 AM | Permalink | Comments (0)
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With the clatter of rain in the gutters overnight and this morning, we've managed to pick up another inch of rain here on the WeatherDeck in Cockeysville. That puts the WeatherDeck past 4.6 inches for the month - well above the long-term averages for the area for all of September. But the official station for the region, at BWI, has recorded only 2 inches, so no surplus there.

Skies should begin to clear tomorrow as high pressure approaches from the north. The weekend looks good - sunny skies and highs in the 70s.

Down at BWI-Marshall, the weather service instruments have recorded only a few hundredths of an inch since yesterday (Wednesday). But totals are higher in other places around the region.

Dunkirk (Calvert):  1.38 inches

Jacksonville (Baltco):  1.15 inches

Chesapeake Beach (Calvert): 0.78 inch

Jarrettsville (Harford):  0.45 inch

Salisbury (Wicomico):  0.26 inch 

So are we liking this rain? And the cool weather? It's only 59 degrees on the WeatherDeck at 10:30 a.m. No AC, no heat ... nice to keep that money in our pockets.

Posted by Frank Roylance at 9:59 AM | Permalink | Comments (1)
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The clouds are closing in, bringing what forecasters say will be several days of likely rain for the region. So today's delightful late-summer forecast of sunshine and blue skies may be the last we see until Sunday.

For now, we're under the influence of a big high pressure system over Eastern Canada. But there is a cold front approaching from the north, and that will bring a gradually increasing cloud cover with more easterly winds late today, and eventually rain. Forecast rain chances climb to 70 percent in the next few days as lows moving along the stalled front drag in more moisture from the ocean and the Gulf.

BWI-Marshall has had almost 2 inches of rain so far in September, just about normal for the month to date.

There is no change yet in the forecast for the beaches, and tonight's planned launch of a 65-foot Black Brant XII rocket from the NASA Wallops Flight facility on Virginia's Eastern Shore. Scientists plan to release a high-altitude cloud of aluminum particles that may be visible from much of the mid-Atlantic region.

The launch window opens at 7:40 p.m. and closes at 7:57. Forecasters gave the launch a 60 percent chance of favorable weather. There's more on the event in the previous post.

Here is the Wallops forecast. Looks a lot like ours.

Posted by Frank Roylance at 8:02 AM | Permalink | Comments (0)
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The forecast from the National Weather Service has been calling for rain in Baltimore every day since the middle of last week. They pointed to a coastal storm and winds off the Atlantic bringing lots of clouds and moisture into the region.

Well, seems like we've had plenty of clouds, and cool temperatures. But the airport has recorded barely a quarter-inch of rain. And out on the WeatherDeck in Cockeysville, we've noted less than a tenth of an inch all month.

Somehow, we've stayed just far enough west and north of the action to remain pretty nearly dry all week. But can we duck the rain much longer?

The official forecast out of Sterling pushes the likelihood of showers today and tomorrow to 70 percent. And tonight's odds are set at 100 percent. If the wettest end of their predictions proves correct, the city could see more than 2 inches of rain between now and Friday night. Any bets?

UPDATE 2:30 p.m. Thursday: Forecasters have already backed off earlier rain amounts. Rain chances this afternoon are now 20 percent, not 70 percent. 

A Coastal Flood Advisory remains in effect through early Friday morning for the Western Shore, from Harford to St. Mary's counties. Tides may run up to 18 inches above predicted levels late Thursday as persistent northeast winds continue to push water onto the beaches and up the creeks.

Winds may pick up, too, as that coastal low continues to hang out near the mouth of the Chesapeake. Gale warnings are posted for the Maryland portion of the Chesapeake through midnight Thursday night as the low approaches. 

Conditions look dicey for the beaches, too, with Coastal Flood, High Surf and Wind advisories posted for Ocean City. Gusts could reach 45 mph. Tides could be 2.5 feet above predictions, and the risk of rip currents is high.

Be careful out there.

Posted by Frank Roylance at 11:14 AM | Permalink | Comments (1)
Categories: Forecasts
        

Well, at least it's not hot. But there is little to cheer about in the forecast for Central Maryland as it's evolved in the last few days.

The coastal storm we've been writing about will continue to send cool, moist Atlantic air our way, with a risk of showers in the forecast for Baltimore all week. And the persistent easterly and northeasterly winds will drive ocean and bay waters ashore on the east-facing shorelines, with a risk of minor flooding as a consequence. The high tide may be exaggerated anyway because we have just passed the full moon on Friday.

The National Weather Service has posted a Coastal Flood Advisory for Anne Arundel County from 6 p.m. Tuesday night to early Wednesday morning. That will cover this evening's high tide, at around 8:40 p.m. at Annapolis. Forecasters warn:

"MINOR COASTAL FLOODING WILL BE POSSIBLE AGAIN DURING HIGH TIDES
WEDNESDAY AND THURSDAY AS LOW PRESSURE NEAR THE MOUTH OF THE CHESAPEAKE BAY
AND STRONG EASTERLY WINDS COMBINE TO PROMOTE POSITIVE TIDAL
ANOMALIES."

There are coastal advisories for the Eastern Shore, too.

Posted by Frank Roylance at 11:26 AM | Permalink | Comments (0)
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Last week's NWS forecasts for a sunny week having been, um, revised, the coastal low that's partly responsible for the change is threatening heavy rains, coastal flooding, strong winds and rip currents from Ocean City southward to the Outer Banks.

This is not a tropical storm, and forecasters say there's only a small chance it will become one. But it is a spoiler for anyone planning to enjoy some extended post-Labor-Day beach time. The weather service says winds will be running 15 to 25 mph along the coast, with surf in the 4 to 6-foot range, and a high risk of dangerous rip currents. Here's more on that.

There are also flood watches posted Monday night and Tuesday for portions of coastal Virginia and North Carolina. Here's more on that.

In the meantime, the 7th tropical depression of the 2009 Atlantic season has formed in the far eastern Atlantic. But it does not appear likely to become a threat to the western hemisphere.  Here is the latest advisory. Here is the forecast storm track. And here is the view from orbit.

If it does make it to tropical storm force, it will become Tropical Storm Fred.

Posted by Frank Roylance at 9:15 PM | Permalink | Comments (0)
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This is why I love living in Maryland; the long, beautiful autumns and springs. Although it is nominally summertime for 18 more days, we have shifted into an early-autumn weather pattern that promises more mild and pleasant temperatures and dry air as far as the old weather-eye can see. Which is about a week.

High pressure over the Great Lakes continues to spin clockwise, pulling cool, dry air down from New England and Canada, holding hotter, more humid and rainy weather at bay well to our south and east. The weak coastal low that is sending rain bands into coastal New Jersey and Long Island won't make it here. So we're cleared for a terrific, long Labor Day holiday.

The fine weather is slated to stretch well into next week, with some moisture creeping in toward the end of the 7-day outlook.

And that outlook beats Honolulu's forecast hands down. They're looking at temperatures in the high 80s, with showers likely both day and night. We're expected to see highs mostly in the lower 80s (except for Saturday, when we could reach 87 at BWI) with no rain in sight.

Out at the beaches, temperatures will be a bit lower - near 80s degrees. But skies should stay clear. The only worry for holiday visitors will be the onshore winds, which are forecast to bring some rough surf and a moderate risk of rip currents.

In the meantime, Tropical Storm Erika has fallen apart (left), and its remnants are expected to stay well east of Maryland after the middle of next week, with no impact here.

Party on. 

(SUN PHOTO/Barbara Haddock Taylor 2008)

Posted by Frank Roylance at 9:56 AM | Permalink | Comments (2)
Categories: Forecasts
        

Now this is pretty darm near perfect. Canadian high pressure is parked over the Great Lakes, putting us in a nice northerly  or northeasterly flow of cool, dry air. Sunshine, low humidity and pleasant temperatures right through to the weekend.

We may see a few fair-weather clouds around as humidities slowly rise. And a coastal low could throw some clouds back our way, and maybe an overnight shower this weekend.

But all-in-all, it's relatively cool and dry right into the middle of next week, with highs no higher than the low 80s. Sweet.

Best of all, we can open the windows (well, not here at Calvert & Centre), and let the breeze sweep through.

Blankets and silent air conditioners are the rule all night long, with lows in the 50s, maybe even 40s and upper 30s in the far western counties.

Tropical Storm Erika, meanwhile, appears to have weakened some overnight, as expected. The storm is pretty badly organized for now, and is forecast to weaken further in high-level wind shear as it moves toward the Bahamas. Computer models apparently disagree over whether this storm will survive. The National Hurricane Center thinks not. Here's a snippet from this morning's NHC discussion:

"DESPITE ALL THIS
SHEAR...ALL RELIABLE GUIDANCE RESTRENGTHENS THIS SYSTEM TO NEAR
HURRICANE STRENGTH IN A FEW DAYS.  THIS REINTENSIFICATION
DOES NOT SEEM VERY LIKELY AND THE NHC FORECAST IS MUCH LOWER THAN
THE GUIDANCE.  GIVEN THE POSSIBLE SHEAR DURING THE FORECAST
PERIOD...IT WOULD NOT BE SURPRISING IF ERIKA DISSIPATED."

Erika is a minimal tropical storm now, with top sustained winds of 40 mph. It is approaching the Leeward Islands, with tropical storm warnings posted for ANTIGUA, BARBUDA, MONTSERRAT, ST. KITTS, NEVIS, ANGUILLA, ST. MAARTEN, SABA and ST. EUSTATIUS, in case you're headed down there.

Here is the latest advisory. Here is the forecast storm track. Here is the view from orbit.  

Posted by Frank Roylance at 10:45 AM | Permalink | Comments (0)
Categories: Forecasts
        

A new month, a new school year, and a new air mass on this final day of the meteorological summer. Everything will seem fresh this week as cooler, drier Canadian air takes over our weather.

The overnight low was just 59 degrees out on the WeatherDeck this morning. At BWI-Marshall, the low was 62 degrees. We've been that cool only twice this month, as compared with our unusually cool July, which saw eight mornings in the 50s. 

Here are some other overnight lows across the region. (The lows for the 24 hours ending 8 a.m. Aug. 31 had not been posted at this writing, so be careful to check the date on the map.)

A quick check found lows of 62 at Dulles International Airport; 64 degrees at Reagan National; 66 degrees in Annapolis; 58 degrees in Hagerstown; 57 at Martinsburg.

The cooler weather comes with high pressure building in from the Great Lakes. You can see the clear air just to our northwest in the satellite view above. The stalled cold front that brought us our showers late last week remains to our south, and we may be stuck under its cloud deck for a time today until that boundary finally gets pushed out to sea.

That will clear the way for what should be a dry, sunny week, with highs in the 70s, climbing to the low 80s after mid-week ... "quite late-Septemberish," the forecasters said this morning. 

Posted by Frank Roylance at 9:46 AM | Permalink | Comments (1)
Categories: Forecasts
        

With a cold front aproaching from the north and west, and Tropical Storm Danny edging in from the southeast, Marylanders are in for a weekend primed for wet and breezy weather.

Forecasters out at Sterling say we'll have one more day of near-90 summer weather today (Thursday). But as we come into a more northeasterly flow around a deep Canadian low to our north, winds off the ocean will begin to bring in cooler, wetter air, with more clouds and increasing chances for showers.

There is a 70 percent chance for showers and thunderstorms by Friday as the cold front stalls over the region, and we get continued northeasterly winds off the ocean.

Saturday is when Tropical Storm Danny - maybe Hurricane Danny by then - comes into play. Some forecast models bring the storm right along the coastline, with more pronounced impacts on the beaches and into the Chesapeake. But forecasters say the most recent model runs keep the storm's center farther offshore, reducing the risks.

Here is the latest forecast advisory for Danny. Here is the forecast storm track. And here is the view from space.

Either way, this will likely be a very wet event, especially for the Eastern Shore, with a couple of inches of rain possible. Here's part of the Thursday morning forecast discussion out of Sterling:

"THE ATMOSPHERIC REGIME AHEAD OF DANNY /REGARDLESS OF ITS EXACT
TRACK/ FOR THE MID ATLC WILL BE ONE OF INCREASING MOISTURE ...

"THIS LIKELY SPELLS LOCALLY HEAVY RAIN FOR INTERMITTENT PERIODS OF
EARLY FRI INTO EARLY SAT. ... W/ SHOWERS AND ISOLATED
STORMS DEVELOPING ... ACTIVITY WOULD BE
FAIRLY SHORT LIVED AND SCATTERED IN NATURE W/ UNFAVORABLE WIND
PROFILES FOR ORGANIZED ACTIVITY...WHICH AGAIN HIGHLIGHTS THE IMPACT
OF LOCALIZED HEAVY RAINFALL /EVEN FROM LIGHT-MOD ECHOES/.

"AFTER THE TROPICAL FEATURE SLIDES WELL TO THE NE INTO LATE SAT...THE
UPPER LOW /OVER THE GREAT LAKES/ RESPONSIBLE FOR KEEPING DANNY OFF
THE COAST WILL KEEP THE EASTERN SEABOARD WELL SUITED FOR MORE SHOWER
ACTIVITY FOR SUNDAY AND INTO EARLY MONDAY."

Finally, once Danny races off toward the northeast, the cold front drops through the region, and cooler, more autumnal weather moves in. Overnight temperatures in Western Maryland could drop into the 40s and to the 50s for the metro areas next week.

We should see highs only in the 70s in Baltimore. Great back-to-school weather, right kids?!

Posted by Frank Roylance at 8:57 AM | Permalink | Comments (0)
Categories: Forecasts
        

Today should see the last of what is now nearly a week of temperatures in the 90-degree range, forecasters say. A cold front now moving into the Ohio Valley will move our way overnight tonight and drop the daytime highs back to the lower half of the 80s well into next week.

But it may well be a wet transition, as the relatively cool Canadian air runs up against this hot, humid Gulf air that we've been sweating in for several weeks. Some of that rain is already visible on radar in the western part of Maryland (above).

Looking back, Baltimore's average daily temperatures have been 1 to 8 degrees above the long-term averages since Aug. 9. Since the 16th, our daytime highs have ranged between 87 and 93 degrees. The "normal" highs at this time of year are around 85 degrees. We're looking at a high of 92 degrees today at the airport, followed by just 82 on Saturday. 

But we'll have to endure a bath to cool off. Forecasters out in Sterling say we're looking at a 60 to 70 percent chance for showers and thunderstorms from late Friday through Saturday night. Some locations may see heavy, prolonged downpours in persistent "training" thunderstorms that form and reform over the same places.

The front will stall here for a time until Hurricane Bill picks up speed and moves out of the way. That will clear the decks for the front to pass through, and admit the cooler, drier Canadian air by Sunday.

Posted by Frank Roylance at 9:01 AM | Permalink | Comments (1)
Categories: Forecasts
        

Temperatures are headed back up toward 90 degrees today and forecasters are warning of more showers and thunderstorms like the boomers that crackled through the region late Tuesday:

"SOME STORMS WILL BE CAPABLE OF GUSTY WINDS AND MAY
WARRANT SPECIAL MARINE WARNINGS FOR THE MARYLAND CHESAPEAKE BAY
AND TIDAL POTOMAC. A FEW STORMS MAY BE CAPABLE OF MARGINALLY
SEVERE WIND GUSTS AND HAIL."

Tuesday's thunderstorms dropped a half-inch here on the WeatherDeck in Cockeysville. BWI recorded less than a quarter-inch. But parts of Baltimore city and county, Harford and Carroll reported more than an inch or rain in thunderstorms. Here are some totals from across the state.

The storms toppled branches and trees and knocked out power to thousands. Bill Stifler caught some amazing mammatus clouds in this shot from Hampden.

And we're not done yet. A lingering trough of low pressure and a continuing flow of moist air from the Gulf will keep us in this pattern until Sunday.

Posted by Frank Roylance at 9:34 AM | Permalink | Comments (1)
Categories: Forecasts
        

If you define a "heat wave" as three straight days of 90-plus weather, we may be on the verge of (only) our second heat wave of the year, and the first (and last) of the summer months.

Sounds odd, doesn't it? But you'll recall we had our first stretch of three 90-plus days (officially, at BWI-Marshall) way back in April. There were no 90-plus days in all of May and June, and July and August (so far) produced no more than two in a row.

But the forecasters out at Sterling are calling for highs of 93 degrees today, and 91 and 90 degrees on Wednesday and Thursday. So, we'll see if we can squeeze another "heat wave" into the summer before it ends (meteorologically speaking) on Aug. 30.

The next weather issue we'll face this week is rain. Showers and thunderstorms - some of them potentially with heavy rain - are in the cards for our area all week, with the highest probabilities (50 percent) tonight and tomorrow. The rain comes to us courtesy of a cold front which forecasters say will stall just to our northwest. That leaves us on the hot-and-humid side of the system, made even more unpleasant by the remnants of Tropical Storm Claudette, which went ashore in northwest Florida and Alabama over the weekend.

A hot sun and the tropical moisture, plus slow movement of the system, could mean very heavy rain totals once the storms fire up, forecasters warn. And that could produce some flash flooding issues as the days wear on.

The next break in the weather comes with the next, stronger, cold front, due here Friday or Saturday. That will come with more rain chances. But this front looks like the big August back-to-school break in the weather that brings us our first hint of autumn. Look for highs Sunday and Monday only about 80 degrees, with overnight lows in to 60s.

(NASA Photo/Aug. 17, 2009)

Posted by Frank Roylance at 9:24 AM | Permalink | Comments (0)
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All these clouds should begin to burn off as we move into the afternoon, ushering in an extended period of sunny and hot summer weather right into next week.

You can thank the arrival of high pressure, which is gradually shoving the stalled cold front and all its showers and storms off to our south and east. That will clear the air here and allow daytime highs to begin to creep higher again. From today's forecast high at BWI of 86 degrees - about right for this time of year - the highs will climb to 90 degrees by Sunday or Monday, if the forecast holds up.

The's no rain in the forecast until Wednesday, when the chance for showers and thunderstorms will rise to 30 percent.

Beach weather will be a bit cooler, with highs near 80 degrees, but with higher risks for showers and thunderstorms as the front takes longer to clear the area down there.

All in all, not a bad way for teachers (and kids) to ease into the end of summer vacation.

(SUN PHOTO by Kim Hairston/July 2009)

Posted by Frank Roylance at 11:39 AM | Permalink | Comments (1)
Categories: Forecasts
        

So I sit down in The Baltimore Sun's Weather Center (my desk), and the instruments for the outdoor weather station report we had more than a quarter-inch of rain in the last 24 hours. And for the month, we've had 1.1 inches.

Out at BWI, they've received more than an inch so far this month, including a trace yesterday.

But out on the WeatherDeck in Cockeysville, we've had barely a third of an inch all month, and nothing in the gauge for two weeks. (We call it the rain-repellant Cockeysville Bubble.) So we've been sprinkling to keep the flowers upright and the grass green.

These summer storms sure are spotty. Please send some our way.

(Loyal readers will note that this is me, writing about a weather trend, which is a time-tested, sure-fire way to end it. We should have rain on the WeatherDeck shortly. Will report back.)

(SUN PHOTO/Doug Kapustin/Sept. 2005)

Posted by Frank Roylance at 10:49 AM | Permalink | Comments (3)
Categories: Forecasts
        

Monday's high of 94 degrees at Baltimore-Washington Thurgood Marshall Airport tied the previous high for this year so far. We last reached 94 degrees on July 16, according to the NWS record books. But as today's print editions note, it was well short of the record high for an Aug. 10 in Baltimore. That mark is still 100 degrees, set on that date in 1900.

Today's record is also 100 degrees, also set in 1900. But we won't get close to that one, either. The forecast high is "only" 92 degrees, with a 30 percent chance we'll see some thunderstorms in the region again.

That storm threat continues at the 20-30 percent level through Thursday as a cold front drops down from New York state and plants itself here for a few days. The front will bring us a bit of relief from the heat, at least, keeping us out of the 90s for the next week or so. The forecast highs for BWI drop into the mid- to upper-80s by Wednesday, not far from the seasonal norms.

That will come as a relief to anyone working outdoors, as the Ravens were on Monday. But few of us have the benefit of misting fans to cool us off. (SUN PHOTO by Amy Davis)

Posted by Frank Roylance at 10:27 AM | Permalink | Comments (1)
Categories: Forecasts
        

Even the NWS forecasters out at Sterling seemed surprised at how cool today is turning out to be:

"TODAY WILL BE COOLER THAN YESTERDAY WITH THE
CLOUDS/SHOWERS...STRUGGLING TO REACH 80 BELIEVE IT OR NOT IN MANY
PLACES."

It's only 73 degrees here at Calvert & Centre streets. That's up from a low of 69 degrees at 8 a.m., but cooler than it was for most of the night. Nice day for eating outdoors. (SUN PHOTO by Barbara Haddock Taylor 2004)

The cause is the cold front that swept across the region this morning, and then stalled just to our south. Low pressure riding along the front has produced a few sprinkles here, but it looks like the risk of rain is diminishing as high pressure begins to build in behind the front, drying things out and clearing the skies. Friday should be sunny and seasonable, with a high in the mid-80s.

A high in the mid-70s this afternoon would be remarkable for early August, but not quite a record. The coolest high on an Aug. 6 in Baltimore was 70 degrees, set on this date in 1993. It's 71 out at the airport as I write this, and we hit a high of 74 degrees just after midnight this morning, so there's no chance of a record there, any way you slice it.

The highest daily low maximum for an August day in Baltimore, by the way, was 73 degrees, on Aug. 5, 1954. The lowest was 62 degrees, set on Aug. 26, 1908 and Aug. 31, 1911.

By this weekend, however, we will all have forgotten about this lucky break. Forecasters are looking for highs of 93 degrees at BWI on Sunday, and 95 and sunny on Monday. If so, Monday will rank as the hottest day of this summer so far. We've had just seven days in the 90s this year - three of them in April and four in July. The highest was 94 degrees at BWI on July 16.

Time to switch off the AC again and open the windows for a few days?

Posted by Frank Roylance at 1:57 PM | Permalink | Comments (0)
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"It's HAWT!" That was my nephew Peter's keen observation around this time of year when the family toured the Gettysburg battlefield years ago. Variations on the theme included, "I'm hawt!," and "Can we go now?" Now he works outdoors all summer running heavy construction equipment. Go figure. 

The average temperatures by early August may have begun to decline from the summer's peak of around 88 degrees, and we can usually expect a nice, cool break by sometime later in the month. 

But that's the average. August can and usually does produce some really hot weather. And Baltimore may be facing the hottest stretch of this unusually cool summer as this week unfolds.

Forecasters out at Sterling are calling for highs around 90 degrees nearly all week, with only the briefest of breaks on Friday.

Look for a high near 90 degrees today as high pressure dominates, with plenty of hot sunshine. Some high clouds may move in later on, followed by some fair-weather cumulus by afternoon. But on the whole it will be a sunny day with few prospects for showers on this side of the mountains.

The next "cold" front approaches from the west late on Wednesday, passing through Baltimore by the evening and providing some relief from 90-plus temperatures as thunderstorms cool things off a bit. The front will stall to our south, keeping highs Thursday and Friday in the more seasonable mid- to upper 80s.

The weekend looks just plain hot as winds turn to the south again and sunshine drives temperatures back into the 90s. Sterling is calling them "possibly the warmest temperatures of the season." Rain prospects look slight.

In short, our unexpectedly "cool" summer appears to be taking a breather, while a more typical Chesapeake pattern of hot and humid gets the upper hand.

You knew it had to happen.

Posted by Frank Roylance at 7:53 AM | Permalink | Comments (2)
Categories: Forecasts
        

After a very soggy spring, somebody has finally shut off the rain valve. Baltimore has recorded no measurable rain for more than two weeks now. The grass that grew so happily through April, May and June has suddenly choked and turned brown. My thickest lawn in 12 years is suddenly begging for moisture.

With some luck, we may get some showers and thunderstorms during the next week or so. The best shot seems like Friday night and Saturday, which forecasters give a 50 percent chance of delivering some precipitation.

For now, we're in for a real summery day, with highs likely to top out in the 90s. West winds are bringing air down the eastern slope of the mountains, which in addition to heating things up, is also drying them out some. The relative humidity here at The Sun is holding in the 50s, so it doesn't feel quite as miserable as it can at this time of year. It only starts to feel uncomfortably humid when the dewpoint reaches 70 degrees or so.

But this won't last long. Forecasters are expecting a series of weak cold fronts, the first arriving here overnight from the Ohio Valley and stalling just to our south. Low-pressure systems tracking along that front could will deliver some showers and thunderstorms tonight or tomorrow. Then, a second, reinforcing front will slide by on Saturday with a higher risk of showers and storms, and cooler temperatures - back into the low 80s by Sunday and Monday.

After a mostly cloudy Sunday, rain chances will begin to rise a bit early in the work week, to 30 percent.

Since June 20, BWI-Marshall has received just 0.48 inch of rain, with nothing measurable since July 1. The dry air has also been relatively cool. Of the last 18 days (June 28 through Wednesday), 16 have averaged cooler than the long-term norm for Baltimore. One matched the average, while just one day - July 12 - was warmer than the norm.

Cooling degree-days so far in July are running at just 65 percent of the long-term average, saving us real money on our cooling bills. The average temperature for July so far at BWI is 72.4 degrees. We still have two weeks to go, but if this were to hold it would be the second-coolest July on record. Only 1891 was cooler, with an average July temperature in Baltimore of 71.6 degrees. 

As dry as it has been, the Drought Monitor map still shows all of Maryland with normal moisture. although unusually dry conditions exist in southeastern Virginia. Streamflow in Maryland remains mostly normal for this time of year.

(SUN PHOTO/Colby Ware 2006)

Continue reading "What happened to the rain?" »

Posted by Frank Roylance at 12:20 PM | Permalink | Comments (4)
Categories: Forecasts
        

This unusually pleasant (for Baltimore) July weather will continue today, with slightly below-normal temperatures, sunny skies and low humidities. But we may be flirting with the 90s again by Wednesday as the cold front that drifted by us over the weekend turns and slides back north as a warm front.

Ninety-degree weather and steamy humidity are what we've all come to expect from living in Baltimore and around the Chesapeake Bay. But somehow, this spring and summer, we've managed to avoid it almost entirely.

Until Sunday afternoon, the only 90-degree days we'd had (officially, at least, at BWI-Marshall) were in April. And those three hot days came before we saw any days with highs in the 80s. Since then - through all of May and June and almost half of July - the hottest we managed was 89 degrees, June 25 and 26.

On Sunday, the airport thermometer did touch 90 degrees, briefly, at 5:10 p.m. But the humidities were low, in the mid-40-percent range, making it much more comfortable if you could get out of the direct sunshine.

By Wednesday and Thursday, however, the forecast calls for temperatures near 90 degrees again, with higher humidities and slight chances for showers and thunderstorms.

Until then, we're enjoying average to slightly below-average temperatures and low humidities in the wake of that cold front, which is now stalled across extreme southern Maryland and southeast Virginia. Tuesday should be sunny and seasonably warm at 87 degrees.

The good news is that this more familiar heat and humidity won't last long. By the weekend, forecast highs drop back into the lower 80s, several degrees below the long-term averages for BWI at this time of year. 

What's becoming more apparent, however, is that the wet weather our lawns and gardens enjoyed from April through mid-June appears to have ended. The airport has recorded just eight-tenths of an inch of measurable rain since June 18.

That's not unexpected in mid-summer. But it shows in our lawns. Grass that grew luxuriantly all spring has suddenly turned brown as rain falls short of its needs. Baltimore - start your sprinklers!

Posted by Frank Roylance at 10:56 AM | Permalink | Comments (0)
Categories: Forecasts
        

Feeling a little warm downtown at the moment (87 at The Sun's weather station), but the airport remains at a comfortable 83 degrees as we write. This mild-for-July weather is expected to continue for the rest of the work week. But hot weather is due back for the weekend, forecasters say.

We're only a week into July, of course, but so far the temperatures for the month at BWI-Marshall are averaging a cool 71.5 degrees. That's 4 degrees below the long-term average of 75.5 degrees for the first week of July in Baltimore.

It can't last, of course. But if it did, it would make this the coolest July on record for the city. The only Julys that come close are 1891, which averaged 71.6 degrees for the entire month; 2000 and 2001, which ended with an average temperature of 72.7 and 72.8 degrees, respectively.

Two days so far this month have failed to reach the 80s, and two nights dipped into the 50s at BWI. No records were broken, but we're all saving a bundle on our cooling bills.

The days ahead look pretty much the same as another cold front slips by. Forecasters see slight chances for precipitation today, followed by some clearing and drier air for Wednesday. More chances for showers return Thursday, with highs only in the low- to mid-80s, which is a few degrees cooler than the long-term averages. Nights will hold in the 60s at the airport.

By Saturday, however, we'll be crowding 90 degrees again, with increased risk of showers and thunderstorms. That will persist until the next cold front drops by, perhaps by late Sunday.

Long-term outlooks still don't see much in store for us in the way of our more typically hot and humid Chesapeake Summer weather.

You're welcome, but please... In lieu of flowers, you may donate to your favorite charity.

(SUN PHOTO by Kim Hairston 2006)

Posted by Frank Roylance at 12:18 PM | Permalink | Comments (1)
Categories: Forecasts
        

You could almost call it a "cool wave." But "cool" is probably not the best word to describe the slightly-lower-than-normal highs and lows in the NWS forecast for the next seven days. A "mild wave," maybe?  Or a "pleasant wave"?

Whatever. It's welcome and it's saving us all money.

The real weather news is that we've slipped into this pattern of what meteorologists out at Sterling are calling "troughiness," as in, persistent low pressure to our north that is sweeping disturbances through the region, giving us plenty of clouds, with daily chances for scattered showers and thunderstorms.

And that seems to be keeping the temperatures in check. Highs for the next week will stall out in the low- to mid-80s. And the overnight lows will sink into the low- to mid-60s (maybe even some 50s in some places) - good sleeping weather if the humidity doesn't bother you. That's all a few degrees below the long-term averages for this time of year in Baltimore, which are in the 86/87-degree range on the top end, and 65/66 at night.

Baltimore seems to have been the focus of last night's rainstorms. One city church was struck by lightning. We could hear the thunder from the WeatherDeck in Cockeysville, but only received a bit of the water. Here at Calvert & Centre streets, however, The Sun's weather instruments picked up 0.92 inch of rain. (The station was down for a few hours this morning after some computer reconfiguration. Should be back shortly.)

And that was close to the most reported anywhere in the metro area. Hamilton reported 1.13 inches to the CoCoRHaS network this morning. Towson reported 0.92 inch. Kingsville, in Harford County, had 0.86 inch. St. Mary's County also got a good deal of rain, though probably from a separate storm cell. BWI reported only 0.37 inch up until midnight yesterday.

Sunday still looks like the best weather day of the long weekend for Central Maryland, with no rain chances in the forecast, partly sunny skies and a high near 84. The 4th comes with a 30 percent chance of showers and thunderstorms, starting after 2 p.m. and continuing into the evening. 

(SUN PHOTO/ Mauricio Rubio/Cooler-than-normal bagpipers in Catonsville parade 2008) 

Posted by Frank Roylance at 10:52 AM | Permalink | Comments (0)
Categories: Forecasts
        

Looks like the long holiday weekend will carry a risk of showers and thunderstorms clear through Saturday night, with a 30 percent risk that storms will impact the fireworks. Sunday's forecast, for now, comes with no mention of rain, so if the pyrotechnics are postponed, Sunday should be ideal. (That's what happened in 2007. Sun outdoors writer Candus Thomson snapped the pic at left at the Inner Harbor on the 5th. Amazing.)

But the highest chances for thunder and lightning come tonight, rated at a "likely" 70 percent. So far, all the convection on radar appears to be well to our west, just beginning to move into western Virginia at 4 p.m. But forecasters out at Sterling seem pretty confident things will fire up around the I-95 corridor by 8 p.m. EDT, and cross the Chesapeake by 10.

After tonight, rain chances diminish to the 20-30 percent range, save for 50 percent tomorrow night. That should allow us some sunshine, at least, and time to enjoy the mild, low-80s temperatures over the holiday weekend.

Headed for the beaches? Here's the Ocean City forecast. Looks like folks headed east will have fine weather after Thursday night. No rain in the forecast at all for the weekend, with highs in the upper 70s and low 80s. Perfect. 

Going west? The forecast for Oakland, in Garrett County looks a bit wetter and grayer. But Independence Day itself looks good. Rain chances return for Sunday. Bring a book.

Posted by Frank Roylance at 3:51 PM | Permalink | Comments (0)
Categories: Forecasts
        

June ended at midnight last night without having delivered a single day in the 90s. May ended the same way. Baltimore - or BWI at least, the station of record for the city - has had just three days in the 90s so far in 2009, all of them in April.

So, does that mean we're in for a "cool" summer ?  "Maybe," said Steve Zubrick, the science and operations officer for the National Weather Service's Sterling forecast office. He's been crunching the numbers for the past few months, and found the following:

1. June 2009 had the fewest 90+ days (zero) since 1979. That's only happened six times since they began keeping official records for the city - in 1886, 1903, 1916, 1972, 1979 and 2009. The average number of 90+ degree days in June in Baltimore is 5.7. Last year we had nine. The record is 18, in 1943.

2. May passed without any highs in the 90s, too. The last time May and June both stayed out of the 90s was in 1979. That's only happened four times: in 1979, 1972, 1886 and 2009.

3. So how do summers with no 90-degree weather in June turn out? Zubrick said the coolest three-month (June-August) summer period on record for Baltimore was in 1903, which saw no 90-degree weather in June. The summer of 1886 was the 6th coolest, and also had no June days in the 90s. The summer of 1912 was the 12th coolest on record, and likewise had no June days in the 90s.

4. On the other hand, that latest long-term forecast for Baltimore for this summer, issued at the end of May, called for a cooler-than-normal June, but above-normal temperatures overall for the 90-day summer period. If they're right, we're in for a hot July and August.

5. As for rainfall, April, May and June together produced 19.74 inches of rain at BWI. That ranks as the second-wettest April-June period on record for the city.

For Zubrick's complete (unofficial and preliminary) report, read on.

(SUN PHOTO/John Makely 2006)

Continue reading "May, June without 90s ... Cool summer ahead? " »

Posted by Frank Roylance at 10:28 AM | Permalink | Comments (5)
Categories: Forecasts
        

It will be hard to find anything negative to say about the weather today. Blue skies, low humidity after the dampness from overnight showers dries up, and temperatures near seasonal averages should make just about everybody happy.

We can thank low-pressure systems to our north. They're drawing air in from the west, and it's being dried and warmed as it comes over the mountains. That will keep skies mostly clear today, with highs in the mid-80s. Might be a bit breezy this afternoon, but that's just going to keep us comfortable in the sunshine.

It won't last, of course. Winds will shift tonight more to the south, bringing in higher humidities. And that will increase our clouds and our chances for showers and thunderstorms on Tuesday and Wednesday. The clouds and showers will keep temperatures comfortable - in the low 80s for the latter part of the week.

Shower risks will stick with us Thursday night into the holiday on Friday. But the 4th itself, and the rest of the weekend will be rain-free with highs in the 80s if the current forecast holds up.   

Posted by Frank Roylance at 7:57 AM | Permalink | Comments (0)
Categories: Forecasts
        

The National Weather Service has issued a Severe Storm Watch for the entire region this afternoon and into this evening as an approaching cold front begins to kick off some thunderstorms. The radar loop above was valid at 3:45 p.m. EDT

Here are the counties covered by the watch. Baltimore City is also included:

ALLEGANY             ANNE ARUNDEL        BALTIMORE
CAROLINE             CARROLL             CECIL
FREDERICK            HARFORD             HOWARD
KENT                 MONTGOMERY          PRINCE GEORGES
QUEEN ANNE`S         TALBOT              WASHINGTON

A Severe Storm Warning was issued at 3:44 p.m. for parts of Washington and Frederick counties. We can expect more as the front moves closer. 

The good news is that the passing front will take the sizzle out of this little heat wave, dropping high temperatures tomorrow back into the mid-80s, near the long-term averages for this time of year. It should also lower the humidity a bit, swinging the winds around from the west (which generally brings high temperatures at this time of year) to the north.

A second cold front due through here on Sunday could generate a few more storms, but by next week we should be enjoying pleasant highs in the mid-80s, with some sunshine and more showers possible around mid-week. Good for the garden.

Speaking of sizzle, we're reading 92 degrees as I write here at The Sun's Weather Desk. We touched 93 degrees a little earlier this afternoon. It's 90 at Dulles Airport in northern Virginia, and 87 at Reagan National.

Out at BWI-Marshall, the high so far looks like 88 degrees, a shade cooler than Thursday's high of 89. The BWI record for this date is 99 degrees, reached most recently in 1954.

Posted by Frank Roylance at 3:25 PM | Permalink | Comments (0)
Categories: Forecasts
        

The National Weather Service forecast office in Wakefield, Va. has issued a Coastal Flood Statement for the beaches from Maryland south to North Carolina (green in the map) that includes a warning of rip currents this afternoon. If you're on the sand, or headed there, it's worth a read:

MODERATE RIP CURRENT RISK IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

LOW PRESSURE WELL OFF THE NORTHEAST COAST WILL SLOWLY WEAKEN
THIS AFTERNOON. HOWEVER...THE COMBINATION OF HIGH ASTRONOMICAL
TIDES...AND LINGERING LONG PERIOD SWELL WILL LEAD TO A MODERATE
THREAT FOR RIP CURRENTS TODAY FOR THE BEACHES FROM OCEAN CITY
MARYLAND...TO CURRITUCK BEACH LIGHT NORTH CAROLINA.

PRECAUTIONARY/PREPAREDNESS ACTIONS... A MODERATE RISK OF RIP
CURRENTS MEANS WIND AND OR WAVE CONDITIONS SUPPORT STRONGER OR
MORE FREQUENT RIP CURRENTS...ESPECIALLY IN THE VICINITY OF
JETTIES...PIERS AND SANDBARS. ONLY EXPERIENCED SURF SWIMMERS
SHOULD ENTER THE WATER

Posted by Frank Roylance at 1:06 PM | Permalink | Comments (1)
Categories: Forecasts
        

Are you ready for some HOT weather? Doesn't really matter. You're going to get it anyway. What has been, until now, a relatively cool June with plenty of rain is about to kick into the 90s in Baltimore. And it's not going to go away quickly.

Forecasters out at Sterling are calling for a high of 92 degrees downtown on Thursday, and readings seem likely to stick near 90 right through the weekend. The forecast highs for the suburbs are only slightly lower. And with the heat comes increasing humidity. Our Chesapeake Summer begins.

This will be the first stretch of 90-degree weather in Baltimore since that surprise heat wave in April that posted three straight afternoons in the 90s (April 25-27). And that came before we had even seen highs in the 80s! Set that freaky weather aside and this will be the first true summer weather in the 90s since last Sept. 14.

The heat comes to us as the low-pressure system that's been hanging off the Atlantic coast for days, dragging relatively cool air and showers down from the north, begins to move away. That's allowing the high that's been COOKING the South and the Midwest to move our way. Here's AccuWeather.com's take on it all.

Lemonade?

Posted by Frank Roylance at 5:06 PM | Permalink | Comments (0)
Categories: Forecasts
        

There may be a few isolated thundershowers around the region by this afternoon. And Thursday could produce a couple more. But the way forecasters see it, this should be a mostly sunny week. Finally.

But all that sunshine in the wake of the summer solstice is going to heat us up a lot. High temperatures by Thursday should be near 90 degrees, and the readings will stay there right through the weekend. Summer is here, with the temperatures to match - about 5 degrees above the long-term averages for late June.

The heat late this week will also likely get the mosquito populations revved up, so you may not be able to spend much time outdoors by then.

So, if you have something you need to do outside, best get it done today, or by Wednesday at the latest. I was out there cutting the grass and seeding some bald spots this morning (working a late shift this week) because I know I won't want to face it by Thursday.

Overnight lows will begin to stall around 70 degrees by Thursday, too. We may need the AC on by then to cool things down for a nice night's sleep.

Forecasters out at Sterling say the relatively cool, breezy weather we've been enjoying comes to us thanks to an unusually strong (for this time of year) low-pressure system off the New England coast. That's dragging fresh breezes down from the north. We could see gusts to 20 or 25 mph this afternoon. 

But we could also get a few little showers or storms from the same setup by afternoon as those disturbances reach the Chesapeake Bay. 

By Wednesday night, a weak cold front could pass through and set off a few more showers, but the risks are low - just 20 percent if the forecast holds up.

Posted by Frank Roylance at 11:04 AM | Permalink | Comments (1)
Categories: Forecasts
        

Perhaps the universe is taking pity on us. We face more chances for showers and thunderstorms through the weekend - and especially Friday night. But the forecast out of Sterling this morning calls for skies to CLEAR by Monday and stay that way, at least through Thursday of next week.

Temperatures, meanwhile, will approach 80 today, and stay in the quite-seasonable 80s for the next week at least, heating up to the upper 80s as the week progresses.

On the other hand, maybe the universe is perverse and cruel. Along with the warmer, drier weather will come mosquitoes. LOTS of them, according to University of Maryland entomologist Mike Raupp.

Raupp tells me that the rainy weather - 19 inches in two-and-a-half months - has provided abundant breeding territory in standing water across the region, and mosquito populations are very high. All it will take now, he says, is for the rain to stop for a time, and the weather to warm up and send the little buggers off searching for a blood meal. It's going to be awful.

Mike Cantwell, chief of Maryland's Mosquito Control Division agrees. He says the saltmarsh and culex populations he's already seeing on the Eastern Shore, and even in Central Maryland, are bigger than any in decades. Landing rates - the number of skeeters that land on Cantwell's crews' arms in an hour - are in double digits, some over 90 per hour.

I peered into the flower pot trays on our patio last weekend and saw more wriggling mosquito larvae than I have ever seen, so I believe him. And while mosquitoes find me unappealing (can't remember the last time I was bitten), they love my wife (and so do I). So I dumped the water from the trays, and will continue to monitor them for new larvae.

It takes no more water than a bottle cap for mosquitoes to get their start in your back yard. So take some time to search out any potential containers, dump them out, turn them over or get rid of them. And get your neighbors to do the same, or your efforts will be in vain.

Mosquitoes already eating you alive? Leave a comment and tell us what your're experiencing, where you are and when they're biting.

Remember, the Asian tiger mosquito, an invasive species introduced to the U.S. in the 1980s, has become the prime mosquito pest in urban parts of the Baltimore region. It is well-adapted to the human environment and is a persistent daytime biter. So while we can stay indoors morning and evening when other species bite, it's harder to avoid being outdoors, in the yard, during the day. They are miserable pests. 

(SUN PHOTO/Nanine Hartzenbusch 2001)

Posted by Frank Roylance at 12:36 PM | Permalink | Comments (4)
Categories: Forecasts
        

The weather service has lots of ways to say it: Showers likely. Showers. Thunderstorms likely. Chance of thunderstorms. Chance of showers. Mostly cloudy. And they've used ALL those labels to describe the weather for Baltimore from today straight through next Monday night.

The wet, gray weather that kicked into gear on April 1 continues to dominate the region, making it easy to forget the few gorgeous breaks we've had, such as last weekend's dry, sunny spell.

Today's weather comes to us straight off the Atlantic Ocean, borne on winds out of the east and southeast, circulating counter-clockwise around a low pressure center to our west. That marine air explains the temperatures, which may not leave the 60s today or tonight; and the gray skies.

Those winds are pushing water up the Chesapeake and holding it there. The National Weather Service has issued a Coastal Flood Advisory through 6 p.m. Wednesday night for low-lying stretches along the Chesapeake and the tidal Potomac River. That switches to a Coastal Flood Watch tonight through Thursday morning.

The advisory and watch warn that bay water may rise 1 to 1.5 feet above predicted levels, and 2 feet at high tides. Moderate flooding of low-lying areas is possible. If you snap any photos of high water today, email them to me (frank.roylance@baltsun.com) and I'll post 'em here.

Any spit and drizzle we may see this morning will likely give way to more widespread rain this afternoon as low pressure presses in from the west. As that low moves by on Thursday, it will bring a warm front, with temperatures rising well into the 70s and a greater risk of thunderstorms.

Friday and Saturday look downright hot as yet another warm front pushes through the area. High temperatures could reach the upper 80s, possibly setting off more thunderstorms. And that will be followed by a another low and MORE rain late Friday into Saturday.

Had enough yet? Sorry. After a cold front brings some relief on Sunday, more chances for showers and thunderstorms appear in the forecast for Monday. You want sunny? Maybe Tuesday.

Since April 1, the instruments at BWI-Marshall Airport have recorded 17.38 inches of rain. That is 8,64 inches above the long-term averages, almost double.

And for the sunshine-starved, it will come as no surprise that the airport has recorded only 10 "clear" days in the 77 days since April 1. Another 38 were rated "partly cloudy," while 29 were "cloudy."

(SUN PHOTO/Karl Merton Ferron/June 2004)

Posted by Frank Roylance at 10:20 AM | Permalink | Comments (7)
Categories: Forecasts
        

Building high pressure over New England and the Canadian maritime provinces early this week is setting up a clockwise flow around the high, and that's beginning to draw a cool easterly flow of Atlantic air into the region. With that come clouds and mild-for-the season temperatures.

Forecasters out at Sterling are calling for highs in the 70s Monday and Tuesday with plenty of clouds. (Average for this time of year is around 83 degrees.) But the breather we've enjoyed from the rain should continue, at least until mid-week.

By Wednesday, forecasters say, low pressure moving into the Great Lakes, and the counterclockwise flow around the center, will begin to draw warmer, wetter air into the region from the south and west. And that will boost humidity and increase our chances for showers and thunderstorms into the 30-40 percent range for the rest of the week and into the weekend. Temperatures will rise, too, reaching the 80s by Friday. 

But then we knew the fabulous weather we enjoyed over the weekend couldn't last, right? What a great weekend for baseball, and what great baseball it was.

(SUN PHOTO/Kenneth K. Lam)

Posted by Frank Roylance at 10:52 AM | Permalink | Comments (0)
Categories: Forecasts
        

With more than 3 inches of rain already on the books for June, the forecasters out at Sterling say we can expect mostly cloudy skies and at least a chance for more showers and thunderstorms straight through Monday. The nearest day rated at least "mostly" sunny comes next Tuesday.

But hey... school is out, and if your old unconverted analog TV winks out today you'll have all the reason you need to get outside and enjoy. Splash in the puddles, maybe.

The culprit once again is a weak cold front hovering to our north. It's expected to push slowly across the region today, setting off scattered showers and thunderstorms along the way as sunshine peeks through and gets the still humid atmosphere stirred up. 

Things will slowly begin to dry a little Saturday, as the front drops down to the Virginia/Carolina border. But we'll still run a small risk of showers and storms. And the wet weather returns Sunday as a low-pressure system moves into the mid-Atlantic and pushes the old cold front back north across the region as a warm front. We won't get things truly cleared out until late Monday or Tuesday, when sunny skies return with highs near 80 degrees.

So far, June 2009 has continued the wet pattern established in early April. But June has been an unusually wet month for some time. Only three Junes of the last 10 have had less-than-average rainfall.

Thirty-year average:  3.43 inches

2009:  3.11 inches  *

2008:  3.70 inches

2007:  2.20 inches 

2006:  7:32 inches

2005:  3.74 inches

2004:  4.17 inches

2003:  6.96 inches

2002:  2.39 inches

2001:  3.58 inches

2000:  5.54 inches

1999:  2.04 inches

* Through 10 a.m. June 12

Posted by Frank Roylance at 10:01 AM | Permalink | Comments (3)
Categories: Forecasts
        

 Sterling radar is showing some new thunderstorms developing to the north and west of the Baltimore area. They are drifting very slowly to the east, and forecasters say we can expect these or others to cross the urban corridor later this evening.

Here's the radar loop. And here is the view from orbit as of about 5:15 p.m. You can see the storms as the knobby spots on the otherwise smooth cloud cover.

Severe storm and flash flood warnings (orange on the map) were posted for parts of Frederick, Carroll, Baltimore and Harford counties and Pennsylvania counties just above the state line as a slow-moving storm churned along the Mason Dixon Line.  

Chief threats include hail, strong downbursts of wind and heavy rain.

These storms are popping up in advance of what forecasters say is the main storm-maker, which is still in West Virginia. We could be seeing showers and thunderstorms well into the evening.

Posted by Frank Roylance at 5:33 PM | Permalink | Comments (0)
Categories: Forecasts
        

Hot, humid air and lots of sunshine will set us up for more showers and thunderstorms late today. Forecasters out at the NWS Sterling forecast office  there's a 30 percent chance of storms this afternoon, rising to 50 percent tonight. Those chances climb to 60 percent on Thursday.

And so long as your power stays on, your kids are safe, your basement remains dry and no tree falls on your house, that's fine. These storms can be dramatic and quite beautiful. Yesterday's tumult brought out several intrepid photographers who snapped some great shots of the wild clouds and rain that accompanied the late-afternoon storm. (See yesterday's post.) The one above was shot in Hunt Valley by Art Huffman. We use it with his permission.

The Hazardous Weather Outlook issued by the NWS this morning says scattered showers and thunderstorms today "may become severe this afternoon, with the potential for large hail and damaging wind gusts. The best chances of severe weather will be across the western suburbs of Washington D.C. and the city of Baltimore."

That said, those chances today are less than they were yesterday, and less than they will be tomorrow if the forecast holds up.

The main actor here is a stalled frontal system draped from east to west across the region near the Mason Dixon Line. That leaves our air hot and humid, primed for convection to develop and build thunderstorms, which would drift from the high terrain eastward across our region.

A wave of low pressure is forecast to move along the front and across the area tonight, setting off another round of showers and storms with locally heavy rain. Expect more of the same Thursday with a 60 percent chance of storms from after 2 p.m. into the evening.

On Friday, the cold front will finally cross the region, touching off more showers and storms. The frontal passage will only clear things out for a day, with mostly sunny skies Saturday and highs around 83. Our chances for showers and thunderstorms return to 30 percent Sunday evening and Monday.

Had enough yet? I've posted more shots from Tuesday's storm in the extension below.

Continue reading "More storms possible today, tomorrow ..." »

Posted by Frank Roylance at 10:34 AM | Permalink | Comments (1)
Categories: Forecasts
        

(AT 4:15 p.m.) Strong thunderstorms are bearing down on the Baltimore metro area out of the northwest. Severe thunderstorm warnings (orange)are already posted for Carroll,  Frederick, and (4:40 p.m.) parts of Baltimore, Howard, Harford (5:10 p.m.) Arundel, Prince George's counties, with more warnings likely to follow as the storm tracks south and east, across areas now under storm watches (purple).

Three-quarter-inch hail reported in Westminster and Frederick this afternoon. More storm reports here.

Here is the radar loop. And, you can track lightning strikes here.

You can watch the effects in Baltimore on The Sun's weather station, here.

Forecasters advise:

"THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS"

Be safe. And when you can, let us know what you're seeing. Send photos if you can.

There are severe storm warnings and flash flood warnings up for the entire Baltimore area.

Continue reading "T-storms approaching Baltimore region" »

Posted by Frank Roylance at 4:04 PM | Permalink | Comments (1)
Categories: Forecasts
        

There are some pretty good thunderstorms sweeping across the Delmarva this morning as I write, and we had a subtle rumble of thunder out on the Weather Deck sometime around 6 a.m. Not much rain up that way - a few hundredths of an inch.

But there were some more severe AM storms today down in Charles and Prince George's counties, and some tree damage reported. College Park reported more than an inch of rain this morning. BWI airport picked up a quarter-inch of rain, bringing the official June total there to more than 2.5 inches so far.

And there will be more. That cold front to our north and west will push through the region today, triggering more showers and thunderstorms than we saw Monday. After a break late this morning, some storms late this afternoon and tonight could become severe, with large hail and damaging winds.

The unstable weather - with lots of moisture in the air and a hot sun to stir things up - is forecast to continue through the work week as this frontal boundary remains in the area. Thursday looks like an especially active day for showers and T-storms before the next cold front cross the region on Friday. Saturday looks like the only day in the forecast with no rain chances posted. By Sunday and Monday, rain chances return to around 30 percent, with daily risks of showers and thunderstorms.

My grass loves this stuff. But I confess the humidity drove us to switch on the AC last night. Yes, we caved. It's always the humidity that kicks us over the edge in the late spring, not the heat.

Posted by Frank Roylance at 9:56 AM | Permalink | Comments (2)
Categories: Forecasts
        

So how does your dog do with thunder and lightning? What about the cats? They're in for a bout of loud weather this week as the National Weather Service folks out at Sterling predict 30 to 60 percent chances for showers and thunderstorms every day this week.

I've never owned a dog, but I can remember when I was a kid, our cat used to make a bee-line for the boot box under the basement stairs whenever he heard thunder (or sirens). There must be a million pet-and-thunder stories out there.

Here's the set-up: The high pressure that produced the fabulous weekend weather we just enjoyed has moved out to sea.

It's been replaced by plenty of warm, humid air ahead of a cold front to our west. Add sunshine and a series of disturbances moving across the region, you get instability. And that means mostly afternoon and evening showers and thunderstorms.

Reminds me a bit of when we first moved to Baltimore from Massachusetts in June of 1980. It seemed like we had thundershowers every evening that month. We thought we had moved to the tropics. The old Ford Fairmont had black vinyl seats and no AC; it was torture. Of course, the house had no AC, either, for the next five years. Welcome to Baltimore. But, I digress.

Instability this week will be especially high in the eastern half of the forecast area, Sterling says. That means east of the mountains to the Chesapeake Bay. Some of the storms could become severe, with the danger of damaging winds and large hail. Least likely to see storms tonight is extreme Southern Maryland.

Today will be the warmest day of the week, if the forecast holds up. They're calling for a high of 85 degrees at BWI. It's already 80 here at The Sun, with the relative humidity at 74 percent. Anything above 70 percent starts to feel pretty sticky.  But temperatures later in the week will slide a bit, only reaching the low 80s by mid-week, and the high 70s by week's end.

The highest risk of showers and thunderstorms would seem to be Tuesday and Thursday. A cold front arrives Friday, reducing the risk of rain. But that won't last long. Shower chances remain in the forecast, and the warm, moist return flow returns Saturday as that high moves out to sea. 

(SUN PHOTO by John Makely 2004)

Posted by Frank Roylance at 10:48 AM | Permalink | Comments (5)
Categories: Forecasts
        

Okay campers, how many of you shut the windows, and switched on the AC today as temperatures drifted up toward 80 under sunny skies for the first time in forever? 

And how many have thrown the windows open to let the breeze blow through after suffering through endless gray skies, gloom and 2.37 inches of rain since the month began?

Count me among the breeze seekers. BGE (actually, I switched to 50 percent wind energy from Washington Gas Energy Services, and we're already saving money) can wait a few more days for my dough.

The air is moving through the house, bringing with it the sound of lawnmowers and birdsong. My plans for the afternoon include a burger, the hammock, the newspaper, and David McCollough's "John Adams."  

Could your day be any sweeter than mine? If it is, don't read any further ...

(SUN PHOTO/Frank Roylance)

Continue reading "Sweet June weather, at last" »

Posted by Frank Roylance at 12:26 PM | Permalink | Comments (2)
Categories: Forecasts
        

Weather radar shows the bulk of the rainiest weather has now blown past us, with only the tail end of the storm still to our south and west.

Forecasters at Sterling say we still have a couple of hours to go. But the trailing edge of the rain shield should be past us by sunset.

We've clocked another half-inch here at The Sun since midnight, and 2.2 inches since the rain began on Wednesday. We'll get a breather for the weekend. But there's more water on the way next week. Sorry.

In the meantime, many streams in central Maryland are flowing at record volumes for the date (black dots on the linked map). Flash floods and severe storms are being reported from some locations, chiefly in Virginia and Southern Maryland.

Posted by Frank Roylance at 4:11 PM | Permalink | Comments (3)
Categories: Forecasts
        

I'm starting to get messages and comments from people wondering if this rain WILL EVER STOP !!!  They sound a bit edgy - a bit like seasonal affective disorder has seeped into their psyche. Too little sunshine; oppressive, claustrophobia-inducing cloud cover; soggy grass, wet streets ...

Well, we're not done yet. Forecasters see another quarter- to three-quarters of an inch in the cards today before this storm wanders off the coast and drier air pushes in behind it. But there is relief in the forecast, with partly to mostly sunny skies still expected for Saturday and Sunday.

But get out there and soak up the sunshine when it finally appears, because next week we fall back into the same old pattern of showers and thunderstorms, on tap for the balance of the work week.

In the meantime, flood watches are still up through 5 p.m. today for nearly the entire state as the low that moved in from the Gulf yesterday moves out of the Carolinas to the Delmarva Peninsula today. The heaviest rainfall is likely this morning into the early afternoon. Montgomery County is already under a flood warning as rains and saturated soils combine to flood local streams.

Temperatures remain cool, with winds off the Atlantic, out of the northeast. We'll be stuck in the 60s again today, but as the sun comes out tomorrow, we should get back into the upper 70s Saturday to the low 80s on Sunday and on into next week.

So far this month, BWI has recorded 1.73 inches of rain, which is more than an inch above the averages for June through the 4th. That adds to more than 7 inches of surplus rain accumulated in April and May.

Here's The Sun's weather station. And here are some of the rain totals for the 24 hours ending around 7 this morning:

Leonardtown (St. Mary's Co.):  1.22 inches

Thurmont (Frederick):  1.08 inches

Odenton (Arundel):  0.84 inch

Hamilton (Baltimore City): 0.75 inch

Cockeysville (Baltimore Co.):  0.75 inch

Columbia (Howard):  0.70 inch

(SUN PHOTO/ Elizabeth Malby 2007)

Posted by Frank Roylance at 10:57 AM | Permalink | Comments (5)
Categories: Forecasts
        

"Tonight could be a very busy one for forecasters and emergency workers," say the NWS forecasters out at Sterling. After near-record rain in May, and a fast start on June's rainfall totals, forecasters are looking at the addition 1 to 2 inches of new rain that is approaching the region tonight and tomorrow and say flatly that flooding is likely.

Flood watches issued earlier today have been expanded to encompass the entire Maryland forecast area from Allegany County east to the Chesapeake Bay. Rain will begin this afternoon, become heavy tonight and continue tomorrow as a new low-pressure system moves from the Gulf into the Carolinas and the Delmarva Peninsula by tomorrow afternoon.

The forecast calls for up to a quarter-inch in Baltimore today, with another 1 to 2 inches on top of that tonight. Tomorrow could bring yet another three-quarters of an inch. Here's the water vapor loop from orbit, showing all that tropical moisture gushing into the Eastern U.S.

That's way more than is needed to trigger flooding, forecasters said.

"In the Washington DC metro area rainfall values that could initiate flooding are extremely low due to the heavy rains of the past week. Less than an inch and a half in six hours are all that would be needed," forecasters said. "Values of two to three inches in six  hours will cause problems with flooding. It is possible that these amounts may be reached overnight."

After a very dry fall and winter, the skies opened up in April and May with a 7-inch surplus. May, with more than 8 inches of rain, was the second-wettest May on record for Baltimore since they began keeping track in 1871.

June appears to be starting up in the same pattern, with more than an inch of rain at BWI on Wednesday alone. The next few days could bring the June total close to the long-term average for the month - 3.43 inches. We counted nearly two-thirds of an inch last night on the WeatherDeck in Cockeysville. The Sun's weather station recorded 1.3 inches yesterday.

Fortunately, we will have the weekend to begin to dry out. Forecasters are calling for sunny skies and highs near 80 degrees Saturday and Sunday. But then the old, familiar pattern returns, with rising chances for showers and thunderstorms at least through Wednesday.

Got the roof fixed yet, kid? How is everyone else dealing with the rainy weather? Gardens okay? Sump pump still working? Got your gutters and storm drains unclogged? Ready for the mosquitoes?

Continue reading "Did I mention rain? Roll up your pants" »

Posted by Frank Roylance at 10:55 AM | Permalink | Comments (6)
Categories: Forecasts
        

So maybe you haven't had enough rain yet. In that case, we have a fine day - a fine couple of days - in store for you.

A cold front approaching from the north and west today (line of clouds in the satellite image above) will serve as the trigger for showers and thunderstorms across the region. When that's done, we can look forward to a storm system developing around a low in the Carolinas that will likely bring us a more steady rain by Friday as it creeps up the coast. 

The weekend, at least, looks nice.

Today's storms are most likely after 2 p.m. and into the evening. Some could become severe, with large hail, damaging winds and heavy rain - a quarter to a half-inch. The ground around Baltimore is saturated enough from recent rains that if today's rain rates top 1.5 to 2 inches an hour in the Baltimore, we will see flash flooding, forecasters say.

"It's going to be quite a busy day," one Sterling forecaster said. Here's the Northeast radar loop.

Flash flood watches are posted from Frederick to Harford counties, throughout central and southern Maryland and down into DC and Northern Virginia. The watches are in effect from noon through late tonight.

Once the front gets by us and stalls again near the Virginia/North Carolina border, the atmosphere around Baltimore will become more stable, and much cooler. But things will remain wet if the forecast holds up. They're calling for periods of showers and afternoon thunderstorms again, but with afternoon highs only in the 60s - about 20 degrees cooler than today's highs.

By Friday we will come under the influence of the Carolina low, which will pump more Gulf and Caribbean moisture into the region as it slides up the coast. That will mean a more prolonged period of rain for Maryland, especially east of the Blue Ridge.

We'll start to dry out on Saturday, with mostly sunny skies and highs near 80 degrees on both days. Then the next frontal system arrives, bringing a return of showery weather for the new work week. 

Posted by Frank Roylance at 10:27 AM | Permalink | Comments (0)
Categories: Forecasts
        

Temperatures at the airport will rise into the upper 80s across the region today as we remain south of a stalled cold front. But communities along the Pennsylvania line and closer to the front may see some afternoon thunderstorms popping up with a risk of large hail, forecasters say.

The best chance for showers and storms in the Baltimore area will come late on Wednesday, as that stalled front begins to move south. Hail and strong winds are possible with those storms.

With the front past us by Thursday, our daytime highs will be 20 degrees lower than today's, with a forecast high of only 68 degrees on Thursday. Sunshine returns for Friday and Saturday, with highs only in the low 70s.

A coastal low is expected to develop along the Carolina coast on Thursday, and that could bring rain and cooler weather to the beaches for the weekend. The rest of us will remain cool and dry, forecasters say.

Posted by Frank Roylance at 11:09 AM | Permalink | Comments (0)
Categories: Forecasts
        

The first day of the meteorological summer promises to be a peach for Baltimore, with highs near 80 degrees, blue skies and low humidity. But the clouds move in tomorrow, with increasing chances for showers and thunderstorms for the rest of the work week.

Looking even farther ahead, the summer promises to be warmer than average for Baltimore and much of the East and Gulf coasts (left), according to the seasonal forecast from the National Weather Service's Sterling Forecast Office. But the precipitation forecast, for now, shows no clear trend away from the norms.

First, this week: If you slept with the windows open last night you probably awoke to a pretty chilly room this morning. It was 46 degrees out on the WeatherDeck in Cockeysville at daybreak today, and 67 in the bedroom. BWI-Marshall Airport slipped to 46 degrees, too. That's not too far from the record low for a June 1 at Baltimore - 42 degrees, set back in 1966.

We're enjoying the benefits of a high-pressure system, with dry air and clear skies. Radiational cooling did the rest, allowing yesterday's solar heat gain to dissipate back into space. There were frost and freeze watches and warnings posted early today from Pennsylvania to Maine.

So enjoy this gorgeous day, if you can. Tomorrow, the next cold front slips closer to the region, increasing our cloudiness and bringing increased chances for showers and thunderstorms as warmer, wetter air from the south runs into the front. Lows Monday night and Tuesday morning should be milder than this morning's, in the 60s.

The chances for rain increase to 50 percent by late Wednesday into Thursday. The front is expected to stall just to our south by Thursday and Friday, leaving us under cloudy skies with  continuing chances for showers.

The computer models disagree on our weekend weather. The NWS seems to be leaning toward another stalled cold front and more showers. June begins to sound a whole lot like May, doesn't it?

Posted by Frank Roylance at 10:03 AM | Permalink | Comments (0)
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UPDATE: Grand slam homer under a rainbow. Maybe it's a good night after all. Woo Hoo! 

Earlier: Not a great night to be at the ballpark. Baltimore remains under a flash flood watch, with a cold front marching through and wringing a lot of this moisture out of the atmosphere.

Here's the bad news:

"SHOWERS AND THUNDERSTORMS WILL CONTINUE UNTIL EARLY THIS EVENING.
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING VERY HEAVY RAINFALL
WHICH COULD CAUSE FLASH FLOODING. THE MOST SUSCEPTIBLE AREA FOR
FLASH FLOODING WILL BE ACROSS THE WASHINGTON-BALTIMORE METRO
CORRIDOR WHERE A FLASH FLOOD WATCH IS IN EFFECT UNTIL 8 PM.

"IN ADDITION...SOME THUNDERSTORMS ACROSS THE OUTLOOK AREA MAY BE
SEVERE...PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL."

The radar loop shows the bad stuff beginning to clear the area, slowly.

The good news is the front should move through, and begin to clear the skies and dry the air after 8 p.m. The temperature, which never got much above 70 degrees today, will turn toward a damp, chilly low of 64 degrees, with northwest winds 6 to 9 mph. 

Let's hope the game gets the green light and the O's heat things up.

UPDATE: But you already know this. Clouds are thinning and the game is underway.

Posted by Frank Roylance at 6:28 PM | Permalink | Comments (0)
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A stalled front across the mid-Atlantic states, persistent showers and thunderstorms, enough rain to cause flooding ... May appears to be going out the same way it came in.

Rain totals for May at BWI-Marshall were already closing in on 5 inches late yesterday, and may well have topped that mark by this morning. We have had less than a half-inch here on the WeatherDeck in Cockeysville. The Sun's weather station at Calvert & Centre streets downtown has clocked more than three-quarters of an inch since midnight. BWI has recorded almost 2 inches.

Showers and thunderstorms were dropping several inches of additional rain on some locations this morning. Howard County was under a flood warning as heavy thunderstorms unloaded 2 to 3 inches on the Washington DC area. Here's the radar loop.

Rescue crews have already been snatching stranded Maryland motorists from peril this morning. Don't put your life or theirs at risk. Do not try to drive through flooded low spots.

Forecasters out at Sterling are calling for occasional showers and thunderstorms through Thursday as we remain near this stalled front. Low pressure centered in the Mississippi Valley is spinning counter-clockwise, drawing lots of Gulf and Atlantic moisture northward into the eastern states. All that warm, wet air is running into the cold front, where it gets wrung out. And we get wet. That's good for lawns and water supplies, bad for roofers and vacationers.

Me? I have a new, young cherry tree that needs water, so it's okay by me. How about you? Sick of rain yet?

Posted by Frank Roylance at 7:50 AM | Permalink | Comments (6)
Categories: Forecasts
        

That's one big high-pressure system settling over the eastern United States (see map). By this afternoon it will stretch from Texas to Maine. The high brings clearing skies today and diminishing winds after sunset. And that should mean some serious cooling tonight.

The National Weather Service's Sterling forecast office is predicting a low of 40 degrees tonight at Baltimore-Washington International Thurgood Marshall Airport. Patchy frost is possible in the usual cold spots west of the I-95 corridor. Frost advisories and a freeze warning are posted for parts of the state tonight, from Hagerstown west.

A plunge toward 40 would threaten to tie the record low for a May 19 by morning. The record low for a May 19 in Baltimore is 39 degrees, set on that date way back in 2003.

But with the high moving in from the Ohio Valley today, skies will be clearing, and the high May sun will start to warm things up. We may only get to the mid-60s today - still about 10 degrees below the long-term average for this time of year. But the high, and the sunshine, will stick around all week, driving temperatures well above average by Wednesday, with highs near 80 degrees Wednesday through Friday.

But, as luck would have it, unsettled weather is forecast to return by the Memorial Day weekend. Our fate rests with low pressure that's expected to develop over the Gulf Coast. If that low starts sending moisture up the East Coast as the old high moves out this weekend, we would get several days with 30 percent chances for showers and thunderstorms.

Sunny, pleasant workdays, and a showery holiday weekend. Figures.

Posted by Frank Roylance at 10:12 AM | Permalink | Comments (0)
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My mower may choke, but my grass is gonna love this. The forecast out of Sterling today shows "chances" or "likely" showers clear across the page through Sunday night. Thunderstorms are also a possibility each day as an approaching frontal system (visible in the satellite image above) slides back and forth across the region, and daytime heating kicks in to stir up the atmosphere.

Today's sprinkles will likely be replaced by heavier showers and storms by late tonight as the first weather approaches with the cold front, and then stalls on top of us.

Tomorrow looks cloudy, much like today, with chances for thundershowers in the afternoon, especially across the southern counties as warmer, wetter air flows from the south and collides with the colder air at the front. Saturday will look much the same, too, with the additional risk of severe thunderstorms as the cold front finally pushes through. That colder air could even trigger patchy frost to the west of the Blue Ridge.

The new air mass behind the front should mean drier air and clear skies next week, with pleasant highs in the 70s.

Posted by Frank Roylance at 3:29 PM | Permalink | Comments (0)
Categories: Forecasts
        

This is very sweet weather. Perfect, even, with highs around 70 degrees, a nice breeze and plenty of sunshine. But like all good things, this, too will be coming to an end by Thursday, as the high pressure that delivered the sidewalk cafe weather moves east into the Atlantic and up, off the New England coast .

As the clockwise circulation around the high moves east, that will put us in a more southerly flow on the backside of the high. And that will bring warmer temperatures and more moisture.

Daytime highs will climb toward 80 degrees by Saturday. The departure of the big high will also allow a cold front to approach from the west, and once it arrives, it will stall here, placing us in the same situation that brought us so many cloudy, showery days early in the month.

Disturbances moving along the stalled front will set us up for increasing chances for showers from Thursday through Sunday - as much as 60 percent on Saturday afternoon if the forecast holds up.

Then another cold front will finally shove the whole mess out of town, and bring us drier, cooler, sunnier weather again for Sunday and Monday.

So, if you're headed to Pimlico on Saturday for the Preakness, you should bring rain gear to protect your bonnet, a hanky to dab the perspiration from your brow, and a sharp pencil to figure thundershowers and a wet track into your wagers.

Posted by Frank Roylance at 10:40 AM | Permalink | Comments (0)
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It's a good thing they're not trying to launch the Hubble repair mission today from Baltimore. We're looking at cloudy skies for the day, with a 40 percent chance for rain along the way. And there's more of the same expected this evening.

Down at Cape Canaveral, however, the forecast calls for mostly sunny skies, with a high near 89 degrees this afternoon.

The shuttle Atlantis and its crew of seven are set for blast off at 2:01 p.m. Looks like today will be the best opportunity for a clean launch of the three days in this week's launch window. Atlantis is headed for a week of repairs and upgrades to the Hubble Space Telescope (photo below).

UPDATE: Atlantis has launched on schedule and is now chasing Hubble. The repairs begin Thursday.

Tuesday's forecast at the Cape includes a 20 percent chance for afternoon showers and thunderstorms. Wednesday looks about the same.

The Hubble photo at left is the last we'll see from Hubble's workhorse Wide Field Planetary Camera 2, which will be removed and replaced on this mission with the Wide Field Camera 3. The image shows a "planetary nebula" - remnants of an exploding star - called Kohoutek 4-55. It is named for its discoverer, Czech astronomer Lubos Kohoutek, who also discovered the much ballyhooed Comet Kohoutek in 1973, which failed famously to live up to its media hype. Here's more on this final WFPC2 image from Hubble.

You can follow events at the Cape live today on NASA TV. Last time I looked, the crew was preparing to enter the shuttle. Three hours to liftoff if all goes smoothly.

Back here in Baltimore, we're looking at a 40 percent chance of rain after a beautiful weekend and the first relief in more than a week from the persistent clouds and showers that marked the start of May.

We ended up with nine straight days of rain - 3.9 inches in all, although Friday's count at BWI amounted to only a trace. Sunday was the first rainless day at BWI since April 30. Here's the box score:

May 1:  0.02 inch

May 2:  0.01 inch

May 3:  0.82 inch

May 4:  0.84 inch

May 5:  0.42 inch

May 6:  1.21 inches

May 7:  0.56 inch

May 8:  Trace

May 9:  0.02 inch

Happily, most of the week after today looks pretty pleasant, with a few intervals of rain to water the plants. After today's clouds and light showers - spillover from a low-pressure system to our south - pass by, sunshine returns for Tuesday and Wednesday, with highs in the low 70s, as high pressure returns from the north and west.

There is a 40 percent chance of rain again for Thursday as a new cold front presses in. Then, sunny skies resume behind the front on Friday and Saturday - highs again in the low 70s. Sunday brings another cold front and another chance for showers or thunderstorms.

Posted by Frank Roylance at 10:41 AM | Permalink | Comments (0)
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What was that thing, anyway? We've seen precious little sunshine this month. The daily tally of rain down at BWI this month has come to more than 4 inches now, with 1.21 inches recorded on Wednesday alone. That's more than the norm for the entire month of May.

It has rained at BWI every day this month so far, as if anyone needed reminding. And chances for more showers and thunderstorms remain in the forecast each day through Saturday. That would add up to 9 days of rain. Only 31 more days and nights to go before we launch the ark. Be careful what you wish for.

Anyway, here is the tally so far:

May 1:  0.02 inch

May 2:  0.01 inch

May 3:  0.82 inch

May 4:  0.84 inch

May 5:  0.42 inch

May 6:  1.21 inches

May 7 (by my count from BWI through 3 p.m.):  0.83 inch

Grand total to date:  4.15 inches

Normal for a full May:  3.89 inches

Wednesday's rainfall included some very heavy downpours and thunderstorms in some parts of the state, especially in Anne Arundel and Prince George's counties - more than 1.5 inches. Here are some 24-hour rain totals from across the region.

And here is a rainfall map from NWS observers.

Obviously, the heavy rains have filled the region's creeks and streams. The map at right shows streamflow volumes for 3:30 p.m. Thursday. The dark blue dots denote streams at 90 percent of their record flows for this date. The black dots denote streams now at record volumes for the date.

Here's the national map, showing the swath from Mississippi to New England, in blue, that has seen the most persistent rainfall in the past week or so.

For those interested in this evening's scheduled launch of a Minotaur 1 rocket from the NASA Wallops Flight Facility on Virginia's Eastern Shore, meteorologists down there project a 60 percent chance of favorable conditions for launch this evening. Liftoff would come sometime between 8 and 11 p.m. Here's how the cloud cover looked from space this afternoon.

Favorable weather at Wallops does not necessarily translate into a clear view from the Baltimore area. But if we get lucky, this rocket could put on quite a show as it roars into the sky and off toward the east with its payload of five satellites bound for orbit. Hayden Planetarium astronomer and blogger Joe Rao says the launch could be visible from northern Florida to southern Maine, and as far west as Kentucky.

Baltimore-area residents should look toward the southeast as launch time approaches. You can check the status of the countdown on the Wallops Information phone line: 757 824-2050.

You can also get status Tweets from http://twitter.com/NASA_Wallops

For the launch Webcast, go to http://sites.wff.nasa.gov/webcast I just checked the webcast, and it is now up and running. Pretty boring, but working fine.

If we get lucky, and you spot the rocket, please come back here and leave us a comment. Let us know where you were and how it looked. Thanks!

Posted by Frank Roylance at 3:44 PM | Permalink | Comments (1)
Categories: Forecasts
        

If it seems like it's been raining all month, that's because it has. BWI has clocked more than two inches already since the first of the month. And there's more to come as winds across the continent remain largely west-to-east. The "zonal" flow just keeps sending repeated bundles of low pressure and moisture our way, and we get showers.

Here's the tally since May Day. The amounts on some days are tiny, but what we remember is the mist and drizzle, the occasional heavy showers, and the gray skies ... the incessant gray skies:

May 1: 0.02 inch

May 2:  0.01 inch 

May 3:  0.82 inch

May 4:  0.84 inch

May 5:  0.42 inch

Points west have seen much more rain than we have. The National Weather Service has posted Flood Warnings for the Potomac River at Point of Rocks. The river was a foot above flood stage and minor flooding was expected today.

Flood Watches are up for the western part of the state, from Washington County westward. They're expecting as much as two inches of rain. Soils are already saturated, so whatever falls will run straight into the creeks and rivers, producing localized flooding Wednesday night into Thursday.

The NWS has also posted a Hazardous Weather Outlook for today and tonight that includes eastern Allagany, Washington, Frederick, Carroll, Montgomery and Howard counties. They can expect minor river flooding along the Potomac as heavy rains push some streams out of their banks through Friday.

The cloudy, drippy skies forced the postponement of last night's planned launch of the U.S. Air Force Minotaur rocket from NASA's Wallops Flight Facility in Virginia. The rocket is carrying an Air Force remote sensing technology test satellite, along with four other private, university and NASA satellites. Once airborne, if skies are clear across the region the rocket's climb toward orbit should be visible for hundreds of miles around. Another Minotaur launch from Wallops Island in December 2006 was clearly visible in daylight from my front window in Cockeysville. 

The next launch window at Wallops opens at 8 p.m. Thursday. The forecast for Thursday night is a little better, with partly cloudy skies expected for Baltimore.  

That said, the forecast out of Sterling shows no mention of sunny skies here until Sunday. We can expect more showers and thunderstorms right through Saturday. Temperatures will climb toward 70 today, and well into the 70s through Saturday as another low-pressure system slogs through and pushes a warm front across the region. Those highs would be 5 to 10 degrees above the seasonal norms.

Behind that low we should see high pressure work its way into the area behind the next cold front. That will bring cooler, more seasonable temperatures and SUNSHINE by Sunday. The same unfamiliar golden orb may even stick around through Tuesday ... unless it doesn't. Forecasters say the same old zonal flow could deliver another package of clouds and showers anytime during that period.

Keep the umbrellas handy.

Posted by Frank Roylance at 10:24 AM | Permalink | Comments (5)
Categories: Forecasts
        

Or at least that's how it seems. The forecast out of the NWS Sterling forecast office looks exactly like it did at this time last week: Rain chances, showers and thunderstorms as far as the eye can see.

Today marks the fourth straight day of measurable rain at BWI-Marshall Airport, with about an inch and a half in the gauge since Friday, including what's fallen so far this morning. Here are some more 24-hour rain totals from across the region this morning. The Eastern Shore seems to be getting a good soaking.

Easton:  1.51 inches

Denton:  1.39 inches

Ellicott City:  1.35 inches

Pasadena:  1.15 inches

Towson:  0.98 inches

Havre de Grace:  0.72 inches

The problem (if you regard it as a problem) is a stalled cold front draped across the mid-Atlantic states since last week. Low-pressure waves are moving along the front like squirrels on a wire, kicking off showers as they ramble along. It's been great for the grass, and some of it will reach the water tables and continue to raise them up from their winter-drought lows. That's all to the good.

The bummer, maybe, is that the front remains stalled just to our south. And that's keeping us in cool air - maybe 15 degrees below the long-term averages for this time of year - and northeast winds are dragging more cool air and moisture in off the Atlantic. If it feels like we're sailing the North Atlantic out there, that's why.

The rain has been heaviest to our north and west. The NWS has issued flood watches for Washington and Allegany counties in Maryland, and for the Appalachian counties of Virginia and West Virginia

This soggy state of affairs will continue Tuesday, with more cool temperatures and light rain. On Wednesday, the next low to track along the front will lift the front northward as a warm front, raising our temperatures into the high 70s on Thursday and Friday - well above the seasonal norms - with continuing chances for showers and thunderstorms.

The next cold front is due in late on Friday into Saturday, with (surprise!) more showers in the cards. If the forecast holds up, we may finally see a dry day with sunshine by Sunday.

So keep the umbrellas handy and change those raggedy wiper blades. And be grateful we're putting water in the bank for summer. 

Posted by Frank Roylance at 10:41 AM | Permalink | Comments (5)
Categories: Forecasts
        

Look at this forecast. Nothing but clouds and showers (and maybe a thunderstorm thrown in for tomorrow) for the next seven days. Only on Wednesday of next week do we begin to see the word "sun" or "sunny" in the mix.

Oh, sure. We do still need rain. The entire state remains "abnormally dry" on this morning's Drought Monitor Map. The dryness is hydrological, meaning that, thanks to recent rains, agriculture appears to be off the hook for now, but dry conditions continue to trouble water tables and wells. But it is a signal that we do really need more substantial rain - more than would appear to be in the offing in the next week from the "chance" of showers in the forecast.

Temperatures after today will remain around the long-term averages for this time of year in Baltimore - around 70 during the day. Nights will be a bit warmer than the norms, in the 50s.

The exceptions will be today, where we will once again struggle to reach 60 degrees. Yesterday's high was 71 degrees, reached right after midnight. After falling out of the 70s around 2 a.m., we dropped to 53 by 9 a.m. and stuck there, never rising above 56 degrees all day. The overnight low was 50 at BWI. And the forecast high today is only 59 degrees.

The problem is high pressure over southern New England, which is blocking warmer weather from the west, and sending cloudy, cool, damp air at the surface back into the mid-Atlantic states.

On Friday we'll catch a bit of a break, as the high drifts away, and the cold front to our south returns as a warm front, and afternoon highs climb to the mid-70s. That could come with some thunderstorms. But the frontal boundary will be back, stalling across the region for the rest of the weekend and well into next week. From then on, we're looking at cooler, "mostly cloudy" days with "a chance" for showers.

So, maybe it's a good weekend to get the gardening done. But replacing the roof, or working on that pasty winter pallor? Maybe not so much.

Posted by Frank Roylance at 10:12 AM | Permalink | Comments (0)
Categories: Forecasts
        

Today's radar loop shows very clearly the passage of the cold front this morning. The front, as promised, has swept away the premature summer heat that sent temperatures into the 90s this week. It has also introduced what will be a long stretch of damp but cool (or seasonable) weather for Central Maryland.

The forecast out of Sterling this morning shows showers, a chance for rain or thunderstorms right through the weekend. The coolest day will be today, with highs struggling to reach 60 degrees. The warmest is Friday, with a maximum at BWI near 78 degrees. Nights will be great for sleeping, with lows from 46 degrees (tonight) to the 50s for the rest of the period.

At least we'll be burning very little energy for either heat or cooling.

We end the week with a couple of remarkable numbers on the books. First, three straight April days in the 90s, something that has happened only three times before - in 1929, 1960, and 1976. It was 90, 91 and 91 again on April 25, 26 and 27, respectively. None of those highs tied or broke records, but they came close.

Second, Steve Zubrick, the science officer out at Sterling, points out that this week's spate of 90-degree highs came before BWI had seen any daily maxima in the 80s. That's happened just twice before, he says, on April 27, 1969 and April 20, 1927.

We finally topped out in the 80s on Tuesday, with a high at BWI of 87 degrees.

Amazing.

Posted by Frank Roylance at 10:33 AM | Permalink | Comments (3)
Categories: Forecasts
        

Hang in there, Maryland. This premature high-summer weather can't last. The 90-degree temperatures will expire after today. We'll have one more warm day, and then everything will return to normal. Here, below, is how we looked Sunday from orbit, as we basked in the sunshine.

By Wednesday we'll be back in the low 70s, and Thursday will stall out in the low 60s as the next cold front slips by and stalls to our south. That will be a 30-degree drop in daytime highs, and it will also bring us better chances for showers for the rest of the week.

In the meantime, however, we'll have to contend with the heat. After threatening a record high yesterday (we fell short at 91 degrees at BWI - a degree short of tying the record), we're headed for a high of 91 again today if the forecast holds up.

As wind gusts pick up this afternoon, meteorologists are warning that the effects of heat and drying humidities (37 percent relative humidity in Baltimore at last check)will elevate the dangers of wildfires. The "enhanced fire threat" will continue from late Monday morning until early Monday evening. "If you plan to burn, please check with your local authorities before doing so," the weather service advised.

Once again, this April heat wave comes to us courtesy of the big high-pressure system still spinning off the Carolina coast. Circulation around all highs is clockwise, so we are getting winds out of the southwest and west. Already dry, these breezes are dried further and heated as they sweep down the eastern slopes of the Appalachians. And we see 90-degree readings.

We reached 91 degrees yesterday out on the WeatherDeck in Cockeysville, and 94 degrees at The Sun's weather station at Calvert & Centre streets. We're at 87 degrees here now, at about 11:30 a.m. You can check the newspaper's readings anytime. It's updated every 10 miniutes, day and night. Click here and save the link to your desktop. 

Although many April dates (18 in all) have record highs in the 90s, multi-day stretches of 90-plus weather like this are pretty unusual, according to Steve Zubrick, science officer for the National Weather Service's Sterling forecast office. In fact, this is the first 90-degree April weather at BWI since 2004.

Steve tells me the longest sequence of consecutive 90-plus days in April at BWI is four days, set from April 23-26 in 1960. The highs were 94, 93, 94, 91 degrees.

Baltimore has recorded three-day spells in the 90s on two occasions, in 1976 and 1929.

Today we seem likely to add a third instance, with highs of 90 and 91 degrees on Satiurday and Sunday, plus a third mark in the low 90s today. Adding a fourth 90-degree day on Tuesday will be a bit harder. The official forecast is for a high of 88. But Steve thinks it's a real possibility. 

Posted by Frank Roylance at 11:12 AM | Permalink | Comments (0)
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Temperatures reached a high of 90 degrees at BWI yesterday afternoon, and it looks like we're in for more of the same straight through Tuesday as we remain under the influence of a Bermuda high sitting off the Carolina coast. 

Yesterday's high at BWI did not challenge the 94-degree record for the date, set back in 1960. (Ninety-four is also the highest reading on record for April in Baltimore, matched on two days in April 1960, and once each in 1941 and 1896.)

We recorded a high of 86 degrees here at The Sun on Saturday. It's already 86 here as I write Sunday morning at 10 a.m. We had a high of 91 degrees out on the WeatherDeck in Cockeysville on Saturday.

Here are some other highs reported Saturday from across the region. (Easy to forget it was 29 degrees at BWI just 12 days ago, and that we recorded traces of snow there on April 7 and 8.)

Today's forecast out of the Sterling office calls for a high again near 90 degrees (that's the 5 p.m. temperature forecast map at left), but I'll be surprised if we don't exceed that number. The record for Baltimore on an April 26 is 92 degrees, set in 1990. I'll go out on a limb here and predict a record high at the airport this afternoon.

UPDATE: Nope. The high at BWI was 91 degrees, although we did reach 93 at the Inner Harbor. The forecasters had it right.

As air at the surface heats up, it will rise, drawing in cooler air from over the bay. That bay breeze should keep things cooler along the western shore. But it may also help to fuel pop-up thunderstorms west of I-95 like the one that boomed over Baltimore Saturday evening.  

Sunny and hot weather will continue through Tuesday, if the forecast holds up, with Monday's forecast high at 90 again, and only slightly cooler - 89 degrees - on Tuesday.

That's when the next cold front will finally start to press into the mid-Atlantic states. High, cirrus clouds will start to show up on Tuesday ahead of the front. By Wednesday, we should be looking at a chance of showers and thunderstorms, with highs only in the 70s. Winds shifting to the east will bring in cool, moist air. More chances for showers will persist into the weekend.

Posted by Frank Roylance at 9:47 AM | Permalink | Comments (0)
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Ya gotta love April in Baltimore. Overnight lows this morning sank well into the 30s across a good deal of the region. There was a low of 37 reported from Towson, with minimums near the freezing mark above the Pennsylvania line and even lower elsewhere to our west. Here is a map of low readings from NWS observers.

And now the forecast is calling for a Baltimore high in the 70s this afternoon, climbing well into the 80s for Saturday through Tuesday. We haven't seen the 80s around here since Oct. 16, so it's going to feel HAWT!

The "normal" (actually, the long-term average) highs and lows for BWI at this time of year are in the mid-60s and mid-40s. But hot weather in April is not uncommon. We touched the 80s on three dates in April last year, and on five dates the year before. The records at this time of year are in the mid-90s and mid-30s.

We're enjoying the nice weather courtesy of a big high-pressure system that's sitting pretty nearly on top of us. As it moves off the coast, we'll come under a more southerly and then southwesterly and westerly flow as the system circulates clockwise around the center. That brings us warmer weather.

Overnight lows over the weekend, thankfully, will remain cool, in the 50s to near 60 degrees. So just open those windows for the night and shut the house up, and close the drapes during the day. You'll sleep better, and you shouldn't have to switch on the AC yet. Plenty of time for that as summer gets near.

Posted by Frank Roylance at 10:57 AM | Permalink | Comments (1)
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As the fog burns off and this morning's sunshine breaks through, it's tempting to expect a sunny day, all day. But forecasters out at Sterling say the solar heating and cold air aloft could set off some thunderstorms this afternoon and into this evening. Small hail and gusty winds could be part of the mix.

Showers - at least chances for showers- also remain in the forecast into Wednesday. But once these disturbances push through, we're set to break into some clear air and southwest winds that may push daytime highs into the 80s at BWI for the first time this year.

Curiously, there is mention of snow showers on the western slopes of the Alleghenies tomorrow and again Thursday morning.

The unsettled weather today and tomorrow is the result of a low-pressure system spinning over the Great Lakes, drawing cool air and precipitation south and east into our region as the atmosphere spins counter-clockwise around the low. As solar heating triggers convection from the surface, the warm air rises into the colder air aloft, setting off convection and the potential for thunderstorms.

The chances for precipitation are set at 40 percent today and 60 percent tonight, dropping to 30 percent tomorrow.

Today's thunderstorms could produce pea-sized hail, with penny-sized stones possible in some spots. The risk continues into the early evening. And, say the forecasters, "A few showers along favored slopes of the highlands overnight ... may mix with snow showers as colder air oozes into the [forecast area]."

Snow showers? What is this? Colorado? Actually, as the polar jet stream continues to dig deep into the Eastern U.S. there is a second mention of snow showers on the western slopes for Wednesday night into Thursday before the precipitation issues dry up for the weekend.

High pressure returns to the region Thursday, bringing mostly sunny skies through the weekend. The forecast high for BWI on Saturday is 82 degrees, with 80 degrees expected Sunday. The last time we saw 80 degrees at the airport was on Oct. 16.

Whatever your plans, remember your sun block and hats. And lets get some hats on those babies, people. There was an awful lot of bad-looking red skin in the locker room Monday morning. Saturday's high of 76 degrees drew a lot of pasty-looking people out into the sunshine. The instinct is understandable, but skin cancer is no joke. And we're just 60 days from the strongest sun of the year.

Posted by Frank Roylance at 9:59 AM | Permalink | Comments (0)
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This week is setting up to look a whole lot like last week as far as when we'll see rain and (eventually) sunshine. What you see out your window is what you get for the next couple of days, although the heavy rain and (possible) thunderstorms will give way to more showery events Tuesday and Wednesday.

But by Thursday, like last week, we will break into a warmer and drier pattern, with highs crowding 80 degrees by Saturday. The weekend, at least from this distance, looks much like this past weekend, which was terrific.

So far, here at Calvert & Centre streets, we have clocked in more than 0.6 inch of rain since it began around 7 a.m. Rain rates have topped 0.4 inch an hour at times. I'd link you to our station, but our data logger remains off line.

The airport has reported about the same amount. Add that to the total for April so far, and we're looking at just over 4.6 inches for the month to date. A "normal" April (the average for the 30-year period from 1971 to 2000) produces 3 inches of rain. Surprisingly, April is, on average, Baltimore's driest month. This time, it is the wettest month here since September 2008, which dropped 7.72 inches at BWI.

We could get as much as another three-quarters of an inch out of this storm before the low drifts off to the east. If thunderstorms develop as a warm front lifts through the region this afternoon, there is also the possibility of large hail and damaging winds, forecasters say. Keep a weather eye out between 3 and 9 p.m.

Then there's yet another low due in on Tuesday, with more showers along the associated cold front. Showers may linger into Wednesday before skies begin to clear out. 

In the meantime, we remain unseasonably cool, with highs today about 10 degrees below the long-term average for BWI at this time of year. By Friday, we'll be in sunshine again, and temperatures will rise well into the 70s, with weekend temperatures 5 to 10 degrees above the averages. Nice.

Posted by Frank Roylance at 10:50 AM | Permalink | Comments (0)
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On today's print weather page, reader and frequent question-submitter Jeff Brauner asks why he hears the term "occluded front" so seldom these days:

"What is an 'occluded front'? Is that sort of an old-fashioned term that modern meteorologists don't use much anymore?" Occluded fronts occur when cold fronts sweep counterclockwise around a low-pressure center and overtake slower warm fronts on the other side, lifting the warmer air. Meteorologists do use it. Maybe they skip it in forecasts to avoid explaining it."

As luck would have it, there is a low-pressure system drifting our way today and, lo and behold, it has an occluded front extending southward from the center. It's the purple line in the weather map below. So as the showers arrive later today, you can amaze your friends by saying, "Hmmm, seems like rain associated with an occluded front."  And please report any instances of weather broadcasters actually using the term.

You ask. We provide. Your full-service weather blog.

Posted by Frank Roylance at 8:25 AM | Permalink | Comments (0)
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Had enough rain and drizzle yet? Doesn't matter. We're in for another day of it today, although the menu should change to showers this afternoon and taper off overnight as this coastal low finally moves out to sea, and drier air slips in behind it.

The consolation prize will be a glorious weekend, with highs near 60 tomorrow rising to near 70 degrees for Friday and Saturday - all in sunshine. Springtime for Baltimore, at last.

But first, the rain. We've added another 0.64 inch in the last three days, on top of the 0.87 reported from BWI for Saturday. The month of April has seen almost 3 inches already, more than 1.5 inches ahead of the average pace for the month at its halfway mark.

Some locations have reported more, some less. Here are some 24-hour totals from across the state. 

Beyond the weekend, forecasters are looking at - more rain. A storm system now gathering itself together in the intermountain west is expected to spin this way by late Sunday or Monday. They're not sure how intense the system will turn out to be, but they're looking for more steady rain over two or three days.

Speaking of rain forecasts, researchers at the University of Washington have reported on surveys that suggest only half of us really understand what it means when forecasters say there is a 20 percent (or 50 percent, whatever the number) chance of precipitation.

An article in the Bulletin of the American Meteorological Society says many of the college students answering the survey believed, for example, that a 20 percent chance of rain means readers should expect rain over 20 percent of the forecast area, or for 20 percent of the time covered by the forecast.

What it actually means is that on 20 percent of the days with identical atmospheric conditions, there was rain. It's a probabilistic forecast, meaning there is also an 80 percent chance there will be no rain at all. Including that extra bit of information - the chance of no rain - greatly enhanced the students' understanding of the forecast, the study found.

And that understanding can have real economic consequences for people making decisions about such things as school closures, crop protection and snow clearing, the authors assert.

"A person who thinks that a probabilistic forecast means that a weather event will occur (in some percent of the area or for some percent of the time) may be more likely to take expensive precautionary action than someone who realizes that there is only a chance of that event occurring," according to a news release on the study.  

You can read the entire release by clicking the link below.

Continue reading "Sunny and 72 degrees ... but not yet" »

Posted by Frank Roylance at 10:36 AM | Permalink | Comments (1)
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Back in the saddle after a week off, during which I managed to catch a vacation cold, which I converted into an extra day off. But the good news is that despite the dreary skies - or rather because of them - we have returned to find a beneficially wet April underway. Writing about the drought two weeks ago seems to have helped. No charge.

The rain total for the month so far at Baltimore-Washington International Thurgood Marshall Airport stands at 2.76 inches. That's 1.44 inches wetter than the average April (through the 13th). Most of that rain has come from two very wet days - on the 3rd (1.55 inches) and on Saturday (0.87 inch). My new cherry tree seems quite happy.

Here are some daily totals from across the state. They've seen more than an inch in the last 24 hours in parts of Southern Maryland and the Eastern Shore, where they need the rain most. We've had more like a third- to a half-inch around Baltimore in the last 24 hours.

Keep your umbrallas handy. The forecast promises still more rain through Wednesday night - more than an inch of additional moisture - and maybe as much as two if we get lucky. That could make this the first month in Baltimore with a surplus of precipitation since last September. Depending on when you start counting, we are still working with as much as a 6-inch rainfall deficit. The total deficit since Jan. 1, 2009 is almost 4 inches. The slow, soaking nature of this precip helps even more than a heavy downburst would.

We can thank a low-pressure center just to our south and west. Its counter-clockwise spin is drawing cool, wet air in off the Atlantic Ocean. We'll get still more rain in the next 24 hours as the low moves off the coast and drags still more marine moisture our way, along with increasing winds into the late evening Wednesday.

It's all good, though. The rain we're getting this month should help Maryland's farmers get their planting done and get the seeds germinated properly. What's really needed now are some sustained surpluses to bring the water tables and streamflows back where they need to be to set up for summer.

All this and a good extended weekend forecast, too: Forecasters out at Sterling are predicting sunny skies from Thursday through Sunday, with highs in the 60s. Then another storm system could bring more rain by Sunday night into Monday.

Posted by Frank Roylance at 10:17 AM | Permalink | Comments (1)
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Now THAT's rain we can use. As I write, instruments here at Calvert & Centre streets downtown have clocked just over three-quarters of an inch since the rain began falling overnight. The airport has reported more than an inch. And it's still coming down pretty well - more than two inches an hour at times.

Creeks are rising, too. And here are some early rain totals from around the state.

The ride in to work this morning required switching the wipers to "fast." This would all seem to be more than the "showers" and maybe a quarter-inch total predicted by the National Weather Service for the day. Good for us. We need it. So does my new cherry tree.

All of this rain arrives out of the southwest ahead of a cold frontal passage, which could kick off some thunderstorms, gusty winds and hail along the I-95 corridor before it's over this afternoon. The weather service has posted a Hazardous Weather Outlook to that effect for the region.

The weekend still looks fine.

UPDATE: Rain total at The Sun, at 12:30 p.m. Friday:  1.25 inches. The airport: 1.41 inches.

Posted by Frank Roylance at 10:27 AM | Permalink | Comments (2)
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Yesterday at this time the forecasters out at Sterling were predicting rain showers were "likely" during the day Wednesday and into Thursday, with a tenth- to a quarter-inch in the cards for BWI. Well, a check of the rain gauge at the airport this morning finds a whopping 0.01 inch of water wetting the bottom.

The forecast clearly flopped. The cold front slipped by with little more than a spritz and fog.

Here at Calvert & Centre streets, we did a little better, but not much. We picked up 0.04 inch overnight. The Eastern Shore did better, too, recording as much as a third of an inch.

Too bad. More than half the state remains in moderate drought this morning, with the rest rated "abnormally dry." No change from last week's drought map. The inch of rain we picked up along the way hasn't hurt, but it hasn't helped, either.

So today the prognosticators are calling again for showers after 1 a.m. tonight, but with less than a tenth of an inch expected. Showers and thunderstorms are forecast for Friday, with a tenth - to a quarter-inch due before the next cold front passes and skies clear for the weekend. Sunday night and Monday show more possibilities for showers and thunderstorms. But we'd best see it before we believe it.

Posted by Frank Roylance at 9:51 AM | Permalink | Comments (2)
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If you had two wishes for the weather this week, what would they be? My vote would be for a few days of soaking rain (we're still in a drought, after all), clearing in time for a sunny, spring-y weekend (we deserve it).

Well, that's exactly what the National Weather Service forecasters out at Sterling are cooking up for the balance of the week. Today's sunshine will be the last for a while. There's a cold front approaching, and ahead of that we can expect increasing high clouds this afternoon, thickening up overnight, leading to rain sometime after noon Wednesday.

As the wind shifts around to the east and southeast today, communities along the Western Shore of the bay will feel chillier than the rest of us as they get that breeze off the still-cold (46 degrees) Chesapeake.

Wednesday's rain could deliver a quarter- to a half-inch in the afternoon, and another tenth- to a quarter-inch overn ight into Thursday. All of it is welcome on the WeatherDeck in Cockeysville, near which we will be planting a new cherry tree tomorrow.

There's a second storm system due to spin up off the southeast coast on Friday along with another cold front. All that will bring us more rain Friday until the front blows through. Sterling describes that event as a "soaking rain." We'll take it. Streamflow across Maryland is up compared with last week, but falling again.

Behind all this wet weather we can expect clearing skies late Friday, bringing us sunshine and highs in the mid- to upper-60s for the weekend. But don't put away the umbrella. Rain returns next week.

Posted by Frank Roylance at 11:01 AM | Permalink | Comments (2)
Categories: Forecasts