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May 30, 2008

Sunny days wind down; T-storms Saturday


The photo shot yesterday by NASA's Terra Earth Observing satellite shows just how brilliantly clear skies were yesterday over the Northeast. (Wish they skip superimposing the state borders every now and then, and let us see it the way astronauts do!) Here's a closer look.

But high clouds will start to slip in later today as the next cold front and low-pressure system begin to approach from the Great Lakes by early Saturday.

That system will draw warm, moist air up from the Gulf of Mexico, and bring it into collision with the cool air from the north and west, triggering areas of fog tonight and showers and thunderstorms by Saturday afternoon. Chance of precip tomorrow is 70 percent, slipping to 40 percent Saturday night.

Rain amounts are forecast to stick between a tenth- and a quarter-inch - not enough to push this May into the record books for total rainfall. Only a cloudburst over BWI would make up the inch-plus needed to break the 1989 record. But second-best is still pretty impressive:

May 1989: 8.71 inches

May 2008*: 7.52 inches

May 1894: 7.26 inches

May 1960:  7.10 inches

May 1886:  7.07 inches   

* Through 5/29

National Weather Service

Sunday looks sunny, as do Monday and Tuesday. More showers are expected by mid-week.

Image courtesy of the Space Science and Engineering Center, Univ. of Wisconsin

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

May 29, 2008

Mars weather: Sunny and minus-22 degrees F.

 NASA/JPL/University of Arizona


The weather station aboard the NASA Mars Phoenix lander is up and running. Here's the NASA report on today's conditions:

"The weather at the Phoenix landing site on the second day following landing was sunny with moderate dust, with a high of minus 30 degrees Celsius (minus 22 degrees Fahrenheit) and a low of minus 80 (minus 112 degrees Fahrenheit)."

And we want to go there, why?

Here's more from the Canadians who built the station. And here's their weather page.


Posted by Frank Roylance at 6:17 PM | | Comments (4)
Categories: Space weather

Sun weather station archive expanding

Okay, so it will never rival the National Weather Service, or even the BWI data available in the Almanac section of

DavisBut our data archive here at The Sun's little Davis Vantage Pro 2 weather station (like the one at left) is slowly expanding. We have today managed to upload measurements taken between Jan. 1, 2008 and the present, which you can access here.

Next, we plan to upload all the readings we've gathered since the station was established at Calvert & Centre streets, WAY back on Sept. 6, 2006. It's a slow process. It takes about a minute for each day of data, so we will likely have to leave the computer running overnight.

The kink in the system is that, while we're uploading, we can't post current data. That means once the old numbers are moved, we have to go back and recover the readings that we couldn't upload in real time. Then we have to upload those, which means more current data is delayed.  Arrrgghh!

So be patient with us. We're working on it.

In the meantime, if you need to know the barometric pressure at 3:10 p.m. on Feb. 16, 2008 (it was 30.31 inches), or for any other 10-minute interval since Jan. 1, you can look it up here for free. 

The Sun station data has been accessed more than 2,800 times already. Is this Weather Geek Heaven, or what?  

Posted by Frank Roylance at 5:11 PM | | Comments (0)
Categories: By the numbers

Maryland not even "dry" anymore

In case there's still a soul out there who hasn't already figured this out, the drought of 2007-08 in Maryland is finished. Washed out. In fact, there's not an acre in the state that remains even "abnormally dry" according to the latest Drought Monitor map, out this morning.

The nearest spot with soil moisture, streamflow, rainfall or foliage health that still registers as "dry" is a speck of territory in the far southern end of West Virginia. Beyond that, moderate to extreme drought persists in the western counties of the Carolinas. But even that has moderated some in recent weeks.

We've gone from no drought at all on June 19, 2007, to a high of 87 percent of the state back on Oct. 9. Conditions began to improve in December, but even as recently as March 4, nearly half the state (47 percent) was still reporting drought conditions. But ample rains since dropped that percentage to zero by mid-May. Here are the details

We can thank an extraordinarily wet May - the second-wettest on record here since they began keeping track in 1871. There's more rain in the forecast for Saturday, so we may yet challenge the record of 8.71 inches, set back in 1989.

Anyway, here's a nifty animation of the drought as it waned during 2008. You can watch the 2007 animation by clicking here.

 Drought Monitor

Posted by Frank Roylance at 10:55 AM | | Comments (2)
Categories: Drought

May 28, 2008

A stormy Saturday

Sun photo by Karl Merton Ferron, 2007 

I don't think we need to write much about the weather forecast for the next few days. Nothing but warm, sunshiney days and starry nights, from what I can see. Saturday's another story.

Forecasters out at Sterling say they're looking at another cold front moving through for the weekend, and it looks stronger than the one that moved through with a few thundershowers last night. That is raising the spectre of severe storms, with the chance for lightning, hail and damaging winds. They're putting the precip chances at 50 percent. No handicapping on the "severe" part yet.

A heavy storm over BWI could send Baltimore's rainfall totals for the month over the May record of 8.71 inches, set in 1989. We're at 7.52 inches today. It will be a stretch, but it's not inconceivable. (The May average at BWI is 3.89 inches.) 

This is already the second-wettest May here since record-keeping began in 1871.

More showers are in the forecast for Sunday, June 1. But the chances are smaller at 30 percent. That figures. Saturday is my only day off this weekend. Gotta work on Sunday.

That's Sun photog Karl Merton Ferron's photo above, shot downtown in July 2007.

Posted by Frank Roylance at 11:51 AM | | Comments (0)
Categories: Forecasts

May 27, 2008

Sunny skies behind approaching cold front


Say what you want about today's gray skies and threat of rain. But at least it had the decency to hold off until after we enjoyed a perfect Memorial Day weekend. The satellite photo above shows the clouds that have moved down over us from the Great Lakes.

The high yesterday at BWI Marshall was 85 degrees, with strong sunshine. Hard to imagine a nicer day. That was 8 degrees warmer than the long-term average (77) for the date at BWI. The record is 94 degrees, set back in 1914.

Forecasters say we could go even higher this afternoon, reaching 88 degrees at the airport as warm air continues to move in from the south and west ahead of an approaching cold front.

The clash of warm air and cold air along that front brings with it a 60 percent chance for rain, with a risk of thunderstorms in the late afternoon and early evening. Some could be severe along the Chesapeake Bay and in the Baltimore and Annapolis region, forecasters say. If we get one, watch for damaging winds and large hail. Here's the Northeast radar loop.

Behind the front, we can expect sharply cooler temperatures, with strong north winds dropping temperatures into the low 50s tonight, and maybe the upper 40s in the normally cooler spots. Tomorrow will look much different than today, with clear, sunny skies returning, and a high around 70 degrees. That's cooler than last night's low of 74 degrees here at Calvert & Centre streets.

That's good news. It was starting to get uncomfortably warm and humid in the house late yesterday. I was tempted to turn on the AC. But I resisted. We've been enjoying the cool weather this month, and with no need to heat or cool the place, our BGE bill was the lowest of the year so far.  We've had just 12 cooling degree-days so far this month, well below the long-term average of 50 for this time of year at BWI. If only this could continue...

The sunshine should stick around for the rest of the work-week as high pressure builds back into the region. Daytime temperatures will gradually warm back into the 80s until the next frontal system brings showers and thunderstorms for the weekend, forecasters say.

Posted by Frank Roylance at 10:45 AM | | Comments (2)
Categories: Forecasts

May 22, 2008

Tornado videos from Colorado, Hungary


A huge tornado (not the one pictured here) struck near Fort Collins, Colo. today, and was captured on video by a local TV crew as it blackened the sky and pelted the camera operator with hailstones. 

Meanwhile, a fledgling storm-chasing organization in Hungary managed to film a tornado there as it formed on May 20 - a comparative rarity in Europe. Click here for that one.

Posted by Frank Roylance at 3:14 PM | | Comments (5)
Categories: Cool pictures

Caution: Cold water ahead

 Sun photo by Glenn Fawcett May 2007

                                                       A chilly Ocean City in May 2007 - Sun photo by Glenn Fawcett 

Many neighborhood swimming pools will be opening up for the season this weekend. And a few brave souls may be ready to take a plunge into the Chesapeake or the Atlantic as the Memorial Day holiday marks the unofficial start of summer in Maryland.

But it's going to be a breath-taking experience. Here's how Andy Woodcock - a National Weather Service forecaster out at Sterling, put it in this morning's forecast discussion:


Well, our low overnight here at Calvert & Centre streets was 52 degrees, but out at the airport they reported a low of 45 degrees - almost 10 degrees below the long-term average for this time of year. The forecast for tonight puts the BWI low at 47 degrees, creeping to 49 Friday night and 51 by Saturday night.

Daytime highs are running about 5 degrees too cool for this time of year. But the forecast has them rising to  the mid-80s by Memorial Day. If you're headed for the beaches, however, don't expect to see temperatures that warm. Here's OC's forecast.

As for water temperatures,  Ocean City is reporting 58-degree water at the Inlet. The readings are 60 degrees at Annapolis and Tolchester. A defibrillator is advised.

As for the pools, well, I'd advise alerting the lifeguards before you dive in.

Posted by Frank Roylance at 11:49 AM | | Comments (0)
Categories: Forecasts

May 21, 2008

Skies improving for space station flybys


Marylanders should have a decent and improving chance to see the International Space Station Thursday and Saturday evenings as skies begin to clear up in the wake of the latest round of May rain showers. Grab the kids, the neighbors, the neighbors' kids, and amaze them all with your knowledge of the night sky.

The first good opportunity will come Thursday evening as the ISS makes its way along an orbit taking it about 240 miles over New Orleans, Baltimore and Nova Scotia. The forecast here calls for partly cloudy skies. But the station will be reflecting plenty of sunlight, and should be bright enough to spot, even if you have to catch it between the clouds, or through thin clouds, or amid urban light pollution.

Watch for a bright, star-like object rising above the southwestern horizon at 9:30 p.m. If it's blinking, or sports colored or multiple lights it's an airplane. Keep looking. Skipping along at 17,500 mph, the ISS will climb past the closely-paired planet Saturn and bright star Regulus, in the constellation Leo. It will rise 75 degrees above the northwestern horizon at its highest by 9:32 p.m.. That's almost directly overhead as seen from Baltimore.

heavens-above.comFrom there the station and its crew will pass directly "through" the stars of the Big Dipper, and head off toward the Northeast, disappearing at 9:35 p.m.

Saturday's flyby will follow a very closely parallel orbit, tracking north and east up the East Coast of the United States.

The forecast is better than Thursday's. Watch for it rising again above the southwestern horizon - this time at 8:39 p.m. It will pass midway between Saturn and Mars and zip once again through the stars of the Big Dipper at about 8:43 p.m. Then it will fly off toward the northeast, disappearing at 8:45 p.m.

You can get your own ISS predictions - and more - from  They're customized for your location. The Heavens Above sky map here shows the ISS's Thursday path across the sky as seen from Baltimore.

Remember to stop back here after the show and share the experience with those who just don't GET it.

Shuttle astronauts are preparing for another visit to the station, with launch of the shuttle Discovery set for May 31 - next Saturday.

Posted by Frank Roylance at 10:58 AM | | Comments (3)
Categories: Sky Watching

May 20, 2008

A chilly day in May

Another chilly day for Central Maryland today as the high at BWI stalled  at the 56-degree mark. That is 20 degrees below the normal highs for a May 20 in Baltimore, and just three degrees above the all-time low maximum temperature for a May 20 in Baltimore - 53 degrees, set on this date in 1994.

The high here at Calvert & Centre streets managed to climb all the way to 57 degrees after the sun came out.

Back on May 12 the high at BWI was just 50 degrees, and that did set a record for the date, breaking the 126-year-old record of 51 degrees, set in Baltimore WAY back, on May 12, 1882.

They're calling for a low tonight in the 40s. It's great we haven't had to run the AC yet this year. But we sure did have to throw another blanket on the bed last night. The low at BWI this morning was 44 degrees, just five degrees warmer than the all-time record low for the date - 39 degrees, set in 2002.

So far, we're running almost 2 degrees cooler than normal for the month. Rain is way ahead. We're at 7.52 inches so far through today, making this the second-wettest May on record for Baltimore. The record is 8.71 inches, set in May 1989.  May rainfall has topped 7 inches only three other times:

1894:  7.26 inches

1960:  7.10 inches

1886:  7.07 inches

But warmer, drier days are coming. The new forecast from Sterling says the highs this weekend will stretch into the 70s, and to the 80s in time for Memorial Day. That's - well above the mark predicted in earlier forecasts. 

Sun Photo by Glenn Fawcett 2004

 Freckles seeks shelter from light rain during Memorial Day observances in Timonium in 2004. Sun photo by Glenn Fawcett.

Posted by Frank Roylance at 5:39 PM | | Comments (0)
Categories: By the numbers

Last week's rain map revised

The National Weather Service forecast office out at Sterling, Va., has issued a revised rainfall map covering all five days of showers and downpours from May 8 through 12. It's pretty darned impressive, especially if you live in Calvert County or parts of Anne Arundel, Prince George's County and Northern Virginia, where there seem to be patches with more than 8 inches. Feast your eyes: 


Posted by Frank Roylance at 10:01 AM | | Comments (1)
Categories: By the numbers

May 19, 2008

Showers will clear decks for fine holiday weekend

It's a long way 'til Friday, but if the National Weather Service forecast holds up, we can look forward to some terrific weather for the long Memorial Day weekend - sunny skies and seasonable highs in the 70s. But first we have to sit through a couple of days of showers as a Canadian storm system sends a series of weather disturbances across the region.

Here's the deal. It's going to be a bit cool, but sunny today, as high pressure builds behind the cold front that passed by yesterday. That front is what brought us all the showers, and the dramatic clearing late in the day. Here's the link to near-real-time data from The Sun's weather station at Calvert & Centre streets.

The sunny skies and gusty winds today will yield to increasing clouds and a chance for showers late tonight. The low over southeastern Canada is turning counter-clockwise like a water wheel, and it will deliver the first packet of showers tomorrow, with rain likely in the morning before it rotates out to sea.

After a short break and a chilly night in the 40s, the next package arrives on Wednesday, with a renewed chance for showers into Wednesday evening. (No risk of an overnight record low; the BWI records are still in the 30s at this time of year.)

But then the Canadian low that's driving all this drifts away, and we come under the influence of more Canadian high pressure, forecasters out at Sterling assure us. That will mean cool, clear, dry weather from Thursday right through the long weekend. They're forecasting highs in the mid-70s - at BWI - about right for this time of year. 

Friday's a comp day for me. They had me working Sunday writing obits and covering a rained-out Studio 6001 art show in Mount Washington. (That's Sun Photog Ken Lam's photo below. We both got pretty wet out there, but the show's been rescheduled for this Sunday noon to 5 p.m.)

So now I'm looking at a four-day holiday weekend ahead with perfect weather. Hoo-wah! Anybody have any suggestions for how we should enjoy the weather this weekend? Or will the old hammock be just about right?

Sun photo - Ken Lam

Posted by Frank Roylance at 10:57 AM | | Comments (0)
Categories: Forecasts

May 16, 2008

Killer storm names Dean, Felix, Noel retired

 AP Photo

                                                                       Hurricane Dean's wreckage in Mexico - AP Photo 

We don't remember it as a particularly bad hurricane season because there was little impact in the U.S. But three storm names on last year's list for the Atlantic basin have been retired for all time because of the deaths and destruction the storms wreaked across the Caribbean, Mexico and Central America.

Members of the World Meteorological Organization's Regional Association IV Hurricane Committee voted at their annual meeting in Orlando, Fla. to permanently retire the names Dean. Felix and Noel. Normally, name lists are recycled every seven years. So these three would have reappeared on the 2013 list for the Atlantic. Instead, they will be replaced by Dorian, Fernand and Nestor.

Read more about it here.

Hurricane Dean blew into the season's first Category 5 storm and crashed ashore on the Yucatan Peninsula of Mexico on Aug. 21 last year. At least 32 people in the storm's path perished.

In September, Hurricane Felix crossed the Caribbean and it, too, became a Cat. 5 storm. It went ashore in Nicaragua as a Cat. 5 on Sept. 4, the first time two storms have made landfall at that strength in a single season since record-keeping began in 1851. Another 130 people died.

In October, Hurricane Noel formed in the Caribbean and caused great damage in the Dominican republic, Haiti, Jamaica and the Bahamas before it even reached hurricane strength. At least 160 people died.

Posted by Frank Roylance at 3:30 PM | | Comments (1)
Categories: Hurricanes

A month of records in Baltimore


The heaviest rain is moving off to the northeast, but here the drip goes on. We have another half-inch of rain in our rain gauge this morning here at Calvert and Centre streets. That's about what they've receive down at BWI, too. But the airport is well ahead of downtown Baltimore in total rain for the month to date. And they could be headed for a record-wet May.

Chris Strong, the NWS warning coordination meteorologist out at the Sterling forecast office, reports this morning that BWI received 6.17 inches of rain between May 1 and midnight last night. Since then the airport has recorded another .56 inch. That's 6.73 inches in all. And it's only the 16th of May. (The long-term average for May in Baltimore is 3.89 inches.)

Here are some other measurements across the region. Some spots have seen more than an inch.

The record precipitation for a May in Baltimore was 8.71 inches, set back in May 1989. So if we can squeeze out another 2 inches in the next 15 days we'll have a new record.

"It's possible .... 8.71 inches certainly wouldn't be out of the question," Strong said.

Why not? We're already well ahead of the pace when compared with May 1989. In that month, the airport had recorded 5.52 inches by May 16. We've seen 6.73 inches - the most ever here for the first 16 days in May, Strong said.

The creeks are rising again. Here's the streamflow map.

And it's been a month of records. Consider:

May 9: Record rainfall for the date - 1.85 inches. That beat the 1.41 inches that fell on the date in 1919.

May 11: Record rainfall for the date - 1.49 inches. That was more than the previous record of 1.28 inches set on May 11, 1924.

May 12: A record low maximum temperature. The thermometer at BWI reached just 50 degrees Monday afternoon.  The previous record was 51 degrees, set way back, on May 12, 1882. The previous record at BWI, where official observations began in 1950, was 57 degrees, set on May 12, 1960.

May 12: Record rainfall for the date - 2.20 inches, besting the 2.06 inches that fell in 1921.

Forecasters are warning of scattered or isolated thunderstorms this afternoon as a new low moves across the region from Kentucky. "Locally damaging winds are possible," he said. Here's the forecast.

Things should start clearing up tonight. Temperatures could fall to the 40s in many locations as clouds depart and what heat we have is radiated into space.

There's a mostly sunny day in store for Saturday. But get your outdoor activities done on Saturday, because Saturday night and Sunday will get drippy again, with a 30 percent chance of showers. Monday will be better, but there are (still) more showers in the forecast for the first half of next week as a new low moves in.

You prayed for rain last October. This is it.

Oh, and by the way ... the new Drought Monitor map is in and yes, the drought is officially over, even down on the Lower Eastern Shore, where it had held on until this past weekend's rains washed it all away.

Now, the map shows only "abnormally dry" conditions on the southern Delmarva and extreme Southern Maryland on the Western Shore. The national map shows that "severe" to "extreme" drought conditions continue to our south and west, in the southern Appalachians.


Posted by Frank Roylance at 10:41 AM | | Comments (0)
Categories: By the numbers

May 15, 2008

Tidal flooding eases

Tidal flooding along the Chesapeake is easing this morning. High water was flooding low-lying sections of Alexandria as southerly winds and heavy runoff from weekend storms piled water into the Cheapeake and its tidal rivers. A flood warning was issued for Alexandria and the District of Columbia.

This tide chart from Annapolis shows how far the tide readings had risen above predictions. But the red line is now falling closer to astronomical predictions. Coastal flooding advisories remain in place for today along the Western Shore of the bay, but should expire this afternoon.


Posted by Frank Roylance at 7:17 AM | | Comments (0)
Categories: Flooding

May 14, 2008

China quake, Florida fires from space

Satellite imagery can help us visualize large-scale events in ways that TV pictures - even those shot from helicopters - cannot.

Here is a satellite view of the smoke from the Florida wildfires, which is easily seen from space. The smoke can have a serious impact on people living downwind who may have asthma or other breathing difficulties. Here's more on the image.

NASA/Terra Earth Observing satellite

And here is an image developed from radar data gathered from NASA's Shuttle Radar Topography Mission, with an overlay of quake data from the US Geological Survey.

It shows the sharply contrasting topography of the region of China devastated by this week's 7.9 earthquake. The quake was the result of the continuing uplift of the Tibetan plateau - the high country to the west of Chengdu - as the Eurasian continental plate is rammed by the Indian subcontinent in one of the planet's most dramatic manifestations of continental drift. 

The dots represent the main quake (largest circle) and subsequent, smaller aftershocks to the northeast. Read more here.   

NASA/ Shuttle Radar Topography Mission


Posted by Frank Roylance at 1:41 PM | | Comments (0)
Categories: Cool pictures

Dry out today; more rain coming


We'll get one more day to dry out from the weekend storms, forecasters say. Then, a new cold front and associated low-pressure system will bring new rains. You can see the system in the blue and red areas of this satellite image. The precip may pose issues for areas still coping with high water. But for the most part rainfall amounts will not be anything close to what we saw last weekend.

This morning's discussion from Sterling says clouds will thicken this afternoon, and the first chances for renewed shower activity will come late in the day and evening on Thursday. They're calling it scattered and isolated at first, becoming more widespread overnight into Friday before ending after noon. They're talking about a half-inch of new rain at the most. But for some, that's more than enough.

"Flooding concerns would remain ... for the trouble areas of the past few days across north central Maryland and extreme northern Virginia," the folks at Sterling said.  "Needing only around a half-inch of rain to raise area rivers to action stages." On the other hand, they added, "with area rivers beginning to drop out of flood stages and another day to recover ... the incoming rainfall may not be enough to raise concerns, but in a few isolated areas."

Coastal flooding remains a concern, too, as heavy runoff and southerly winds keep lots of water in the bay. Coastal flood advisories are posted through Thursday morning. Watch out for unusually high tides along the bay. There's a coastal flood warning up for Dorchester County, on the Eastern Shore.

Beyond the new rain, we should expect winds to pick up on Saturday morning as the passing low gets wound a little tighter. The weekend looks partly to mostly sunny, with daytime highs near 70 degrees, as the storms move away.

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

May 13, 2008

So how much rain did we get?


Whew! That was a lot of water. But just how much, exactly? The numbers, of course, depend on where you were. The National Weather Service map above shows the heaviest concentration of rain south of Annapolis, chiefly in Calvert County. Here are more rain totals from around the region.

The National Weather Service instruments at Baltimore-Washington International Airport recorded 2.2 inches yesterday, a record for the date. The previous record for rain on a May 12 in Bawlmer was 2.06 inches, set in 1921. It was the third record rain total at BWI since Friday.

Altogether, the airport recorded a five-day total of 6.15 inches. That is 2.28 inches more than the long-(30-year) term average for an entire May in Baltimore. We are also running 4.73 inches ahead of the pace for the first 12 days in May.

The heaviest rain, of course, fell to the south of Baltimore. In fact, our instruments here at Calvert & Centre streets clocked in just 1.61 inches during the Sunday/Monday storm, while the airport saw 3.69  inches. Some locations saw far more, including North Beach, in Calvert County, which topped the state at more than 7 inches.

There's more rain in store. These sunny skies and 70-degree temperatures will hang around for today and tomorrow. But by Thursday you can expect increasing chances for showers as the next storm system and cold front move in from the west, much as they did last week. The next sunshine will be Monday.

Posted by Frank Roylance at 12:19 PM | | Comments (4)
Categories: By the numbers

Clouds are gone; go look for Mercury

Okay Space Cadets ... here's your assignment for tonight. Our long nightmare of endless overcast is over, and the planet Mercury is making one of its best appearances of the year. I want you all out there after sunset tonight to look for it.

Messenger - NASA/APL

It can be tricky. This is no project for the easily discouraged stargazer (or, in my case, Stargeezer). Mercury is the nearest planet to the sun, so it never strays far from the glare of Old Sol. When we see it at all, it is shortly before sunrise, or shortly after sunset.

Throw in air pollution and clouds, which can obscure the view low on the eastern or western horizon, and the trees and buildings that often block our view, and catching a glimpse of Mercury can be difficult. That's why the planet is so often described here as "the elusive" planet Mercury. Here's how Mercury looked on Friday when a very young crescent moon moved in alongside it.

But my Clear Sky Alarm went off this morning, indicating favorable viewing conditions this evening around Baltimore. So I will be out there to get another firsthand look at the planet that scientists at the Johns Hopkins Applied Physics Lab have ben studying with NASA's Messenger spacecraft.

Find a spot with a clear view of the western sky, with as little clutter - trees, garages, hills - on the horizon as possible. Look for a small, steady, star-like point of light hovering over the horizon. Here's an article from Sky & Telescope, with a sky map (below) to guide you.Sky &

Take the kids. Take a pair of binoculars. The kids and their sharp eyes will help you spot it. The binoculars will get you a little closer. 

Oh, and while you're out there, raise your eyes a little higher and find Mars, Pollux and Castor (the two bright stars in Gemini) all in a row, left to right, above the southwestern horizon. Mars will be in the news in two weeks as NASA attempts to land the Phoenix spacecraft in the Martian arctic to search for water. 

Then turn left a bit toward the south and look for a close pair of "stars." The brighter of the two is actually Saturn, where NASA's Cassini spacecraft continues to orbit and send back spectacular images of the ringed planet and its moons. The dimmer of the pair is Regulus, the bright star in the Constellation Leo.

When you're done, come back here, leave us a comment and share the experience. Good luck!  

Posted by Frank Roylance at 11:43 AM | | Comments (0)
Categories: Sky Watching

May 12, 2008

Baltimore Sun weather data now online

It's not fully operational yet. We hope to our get archival data back to September 6, 2006 into the database before too long. But after nearly two years of nagging (me) and head-scratching (the IT folks), we have finally managed to get our weather station on line, where readers can access it.

The station is a Davis, Vantage PRO 2 instrument. It is located near Calvert & Centre streets in downtown Baltimore, and transmits wirelessly to a console in the newsroom. The data is downloaded periodically to Weather Underground, where anyone with internet access can check on conditions in our parking lot.

Hey, if your car is parked there, you care. Right? More seriously, the station provides pretty good, very comprehensive data for weather conditions in downtown Baltimore AWAY from the influence of the waters of the Inner Harbor, where the nearest National Weather Service station is located, and providing only minimal data.

So have a look. I'll be sending WeatherBlog readers there frequently, but you can go there anytime. Click here.



Posted by Frank Roylance at 12:13 PM | | Comments (0)
Categories: Notes to readers

Rain, wind, flooding to ease; sunshine Tuesday


Intense low pressure to our south has been pumping torrents of rain, gusty winds and loads of trouble our way out of the east for the past 16 hours or so. Rain totals are running from well over an inch to nearly 4 inches across the region.

Some locations reported rain totals in excess of 6 inches and even 7 inches, according to this morning's data from CoCoRaHS

Saturated soils and gusty winds to more than 50 mph in some spots have toppled trees. That has brought down power lines. Roads are flooded as many streams rise out of their banks ... Here's a rundown of some of the damage reported to the NWS.

It all reads a bit like a tropical storm. Happily, the whole mess will move out to sea today, bringing us a couple of days of sunny weather before the next cold front brings more rain.

Here are some of the rain totals and top wind gusts for the storm so far:

BWI:  1.75 inches  40 mph

Reagan National:  2.76 inches  50 mph

Dulles International: 3.76 inches

Martinsburg, WV:  2.04 inches

The WeatherDeck, Cockeysville:  1.61 inches  18 mph (about as high as the wind here ever gets, thanks to the anemometer's sheltered location).

CoCoRaHS: Reports from across the state: click here

The heavy rains have pushed streams throughout central and western Maryland to record-high flow rates for the date. Here's the map. Out on the Eastern Shore, strong rains will likely end the moderate drought conditions that have persisted since last summer. We'll get an updated Drought Monitor map on Thursday morning.

The storm's stiff east winds have pushed tides a foot or two above normal for today on the western shore of the Chesapeake. 



A coastal flood advisory will remain in effect  until 4 p.m. today. Inland flooding is also a continuing risk today. A flood watch is in effect until 2 p.m. in the Baltimore area as moderate to heavy rain remains a factor until it tapers off this afternoon. Flooding creeks and streams, and urban runoff, will inundate low-lying areas. 

Never try to drive through a flooded roadway. It doesn't take much water to sweep your car - and you - away. Turn around. Don't drown.


It will be interesting to see the Inner Harbor today as the rain flush out all the trash in the storm drains. Or maybe rains earlier in the spring have already purged the system. Got water? Got a camera? Send us a report.



Posted by Frank Roylance at 7:25 AM | | Comments (1)
Categories: Forecasts

May 9, 2008

Eeeeeeeeeeeeee ... SWAT!

University of Maryland 

                                                              Mosquito larvae, courtesy of the University of Maryland  

All this rain can mean only one thing in Maryland at this time of year. We're setting up for one heckuva mosquito season.

The state Department of Agriculture today said heavy rains and coastal flooding will likely combine with warm weather in the coming weeks to provide "perfect conditions for a sizeable mosquito population."

"Residents in most areas can anticipate the emergence of troublesome numbers of adult mosquitoes within the next two weeks," the Ag folks warned.

Mosquito control crews began spraying known breeding sites two weeks ago in Central Maryland. Ag Secty. Roger L. Richardson urged residents to launch their spring cleanups and clear their properties of debris that holds water and makes ideal mosquito sites. Pet dishes, old tires, flower pots - even clogged gutters and birdbaths - can "seed" your yard with the pesky bugs. Get rid of them. Here's more.

Posted by Frank Roylance at 3:45 PM | | Comments (0)
Categories: Forecasts

Rain subsides, creeks rise, more due


The showers and storms that brought 1 to 3 inches of rain to parts of Central Maryland and Virginia are moving off to our northeast this morning. That's eased back on the rain rates. But, after a brief respite late tomorrow, forecasters say we can expect another round of significant rainfall Sunday and Monday as yet another storm system takes aim on our region. Don't look for any sunshine until Tuesday.

Rain totals reached 1.3 inches here at Calvert & Centre streets by late morning Friday. The instruments at BWI Marshall airport have recorded almost 2 inches since the rains began late yesterday, erasing the precipitation deficit we've run since Jan. 1, and adding about an inch of surplus.

Down on the Lower Eastern Shore, where moderate drought conditions have persisted even as the northern and central counties shook off the water shortages that began last May, heavy rains overnight have surely eased their plight some.

Salisbury Airport is reporting 1.16 inches of rain so far. Accomack Airport, down on Virginia's Eastern Shore, received 0.84 inch. Here are some other morning rain totals from unofficial weather service data:

Washington DC: 1.65 inches

Millersville, AA Co.: 2.28 inches

Edgemere, Baltco.: 2.39 inches

Indian Head, Chas. Co.:  2.43 inches

Baltimore City:  1.43 inches

Bel Air, Harf. Co.:  1.15 inches

Columbia, How. Co.:  1.15 inches

Potomac, Mont. Co.: 1.36 inches

Fort Washington, PG Co.: 3.76 inches

Here are more readings from CoCoRaHS.

The heavy rains have flooded many roads in the region, especially in Virginia and Southern Maryland. Many streams along the I-95 corridor are running at record highs for this date. Here's more on streamflow.

High winds in thunderstorms caused some structural damage in Arnold, Anne Arundel County, near Maryland City in Arundel, and dropped trees onto the southbound lanes of the BW Parkway at Rte. 198.

And there's more to come. Chances for showers will persist into tomorrow, then ease Saturday night. We may even see some stars. But then the next storm system arrives from the west Sunday afternoon, continuing into Monday. 

Here's the radar loop, showing the rains headed away to the northeast. For now.


Posted by Frank Roylance at 11:02 AM | | Comments (1)
Categories: Forecasts

May 8, 2008

Big rains coming

 Sun Photo by Ken Lam - 2006

                                                                             Sun photo by Kenneth Lam - 2006 

Keep those unbrellas handy. The sunbathing is over and an approaching low-pressure system could drop an inch or two of rain on the Baltimore region between this afternoon and Friday night.

Forecasters say the low is tracking our way from the Mississippi valley, and it will be wet, tapping moisture streams from both the Gulf of Mexico and the Atlantic. That could mean a quarter-inch this afternoon, another inch - or two - overnight tonight into tomorrow.

Here's the radar loop.

There are no watches or warnings out in Maryland at this writing, but forecasters acknowledge they "may need to consider flood watch" in the next forecast update. There is also some talk in today's discussion from Sterling that if thunderstorms develop amid all this weather. "there's a decent chance they may start to spin" - a reference to a risk of tornadoes, at least in Central Virginia.

Once this system pulls away late on Friday, we'll get a short break. But Saturday looks like our only sunny day for a while. Another, similar storm system will move in on Sunday, with more rain later on Sunday into Monday - described by forecasters as "a decent soaker, not unlike the tonight/Friday system."

Forecast models then see another brief respite, followed by yet another rain system on Wednesday.

Posted by Frank Roylance at 1:21 PM | | Comments (0)
Categories: Forecasts

Parts of Burma received 23 inches of rain

Satellite imagery has enabled meteorologists to calculate the amount of rainfall parts of Burma (Myanmar) received during its three-day seige by Cyclone Nargis. The totals are impressive - from 1 to nearly 2 feet across much of the coastal region. And all that rain came on top of a storm surge that swept inland with the storm, inundating much of the very low Irrawaddy River delta with sea water.

Death toll estimates, of course, have been horrific if they prove accurate - in excess of 100,000 people, with a million made homeless. Here is the rainfall map. Six hundred millimeters equals 23.64 inches.

NASA Tropical Rainfall Measuring Mission satellite

Posted by Frank Roylance at 11:23 AM | | Comments (0)
Categories: By the numbers

La Nina fading away


La Nina, the periodic cooling in the surface waters of the Central and Eastern Pacific that enhances hurricane formation in the Atlantic and can affect weather across the United States, appears to be fading away.

Climatologists at the NOAA Climate Prediction Center say sea surface temperatures are rising out there, and approaching what they regard as "neutral" conditions in the La Nina/El Nino cycle, known as the "El Nino Southern Oscillation," or ENSO.

Here's more. And, you can watch the cool (blue) waters in the central Pacific warming up (yellow and tan) in the animation above, which is based on satellite observations of the Pacific during the past few months.

This departing La Nina has been credited (or blamed) for the drought that has plagued the West and the Southeast (including southeastern Maryland) since last summer, and for the mild winter, which brought just 8.5 inches of snow to Baltimore. It also played a role in the heavy snows in the upper Midwest and New England.

La Nina is also believed to facilitate Atlantic hurricane formation, but last year's hurricane season was only slightly more active than the long-term averages. Forecasters will be watching this La Nina's final months for any possible lingering influence it might have over this year's hurricane formation.

Although La Ninas can often be followed by El Nino conditions, it is also possible for "ENSO neutral" conditions - more or less average sea-surface temperatures - to persist for a time. Here is a link to NOAA's FAQ page on El Nino and La Nina.  

Posted by Frank Roylance at 10:32 AM | | Comments (0)
Categories: Science

May 7, 2008

Volcanic smog sickens Hawaiians

Formosat-2 - Taiwan National Space Organization 

In Los Angeles, the choking smog comes from the tailpipes of cars and trucks. On the Big Island of Hawaii, it comes from the mouth of the Kilauea volcano, and they call it "vog" (volcanic smog).

Sulfur dioxide gas from the volcano has been wafting across the island for weeks, forcing the closure of portions of the Hawaii Volcanoes National Park. It has also begun to sicken residents of the island, who are reporting coughing, choking symptoms. They are also seeing casualties in their gardens.

Here's a satellite view measuring concentrations of sulfur dioxide emissions. Each little square pixel represents a volume about 13 kilometers square, rising 5 kilometers above the surface. Red incidates a concentration of 30 metric tons of sulfur dioxide inside that little volume, or 845 cubic kilometers. 

NASA Aura Earth Observing Satellite

Here's another view, in visible wavelengths shot from space, showing the sulfur dioxide "vog" plumes blowing across the island and out to sea.

 NASA Terra Earth Observing Satellite

Posted by Frank Roylance at 5:26 PM | | Comments (0)
Categories: Events

Gorgeous, but watch those smokes

 Sun photo - Doug Kapustin 2001

                                         A brush fire in Westernport in 2001 - Sun photo by Doug Kapustin 

Baltimore weather doesn't get too much better than today's. But there is rain in the wings, so enjoy the day. 

Forecasters out at Sterling are looking for highs here today in the mid-80s, with strong May sunshine to bake out the last chill of winter in your bones. Look for sunbathers on the "beach" at Hopkins. Better yet, be one.

Eighty-degree days in early May are at least 10 degrees above the long-term averages. Today's glorious weather comes with a hitch, however. Forecasters warn that Central Maryland will also see falling humidities - down into the 30-percent range. (I'm looking at 40 percent and dropping fast on our instruments here at Calvert & Centre streets. You can watch the humidity drop at BWI by clicking here.)

Add in increasing winds this afternoon, and you get a "heightened fire weather risk" this afternoon. Drop a cigarette in the wrong spot and you could soon have more trouble than you want.

But once today is behind us, we should expect increasing clouds and rain chances into the next few days. Blame the departure of the high-pressure system now over the Carolinas. It has delivered this fine weather, but as it heads out to sea tonight, we'll fall into a return southerly flow from the backside of the departing high. That brings in more clouds, and more moisture.

So, forecasters expect 50 to 60 percent chances for showers and thunderstorms Thursday and Friday. The heaviest totals would come late Thursday and Friday if the forecasters have it right - as much as an inch.

For Saturday, they're looking for a brief break in the weather, with sunny skies but cooler, more seasonable highs near 70 degrees. Then another low is due here Sunday and the early part of next week, bringing us windier and cooler weather.

Here's what today's clear skies look like from the other side of the atmosphere:


Posted by Frank Roylance at 10:41 AM | | Comments (0)
Categories: Forecasts

May 6, 2008

Burma cyclone from space


The terrible cyclone Nargis that swept in from the Andaman Sea onto  the low-lying coastal territories of southern Burma this week killed tens of thousands and left more than a million homeless. It was an impressive storm, even when seen from Earth orbit. Here's more on the image above.

Here's more from AccuWeather,com. And here are some color images shot before and after the storm.

Cyclones are no different than the hurricanes we see each summer in the Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. But the geographic protocol that applies to these storms states that those that affect South Asia are to be called cyclones.

When they occur in the Atlantioc or the eastern Pacific, they're called hurricanes, and when they spin up in the central and western Pacific, they're called typhoons.

Each geographic locale within those larger regions also gets its own list of names. It's a bewildering array. And, each region sets its own rules.

Our hurricane names run in six-year cycles, so that a list repeats in the seventh year, minus any that have been retired because of their notoriety. The names also alternate between male and female, and mix the cultural origins of the region. 

But the other lists draw from their own ethnic name traditions and cycle with different patterns.

Nargis is the sixth name on List 2 under the Northern Indian Ocean category. The next cyclone out there will be Abe, followed by Khai Muk. Go figure.

Our first three storms this season will be Arthur, Bertha and Cristobal.

Speaking of hurricanes, today I spent a few hours observing as the Maryland Emergency Management Agency staged its annual hurricane exercise, at the state Emergency Operations Center in reisterstown.

They have been simulating the approach of Hurricane "Zoe," a Category 3 storm that appeared to be headed straight for the mouth of the Chesapeake Bay.

(It was an interesting name choice. The Atlantic hurricane name list doesn't go to "Z." Not enough names available that start with "Z." And, while hurricanes have formed in May, the Atlantic basin naming protocol insists that each season's names start at the top of the alphabet, not the bottom.)

More than 80 participants from state and local agencies across Maryland gathered to grapple with the threat of such a storm. The script-writers said Zoe would crash ashore Wednesday afternoon with top sustained winds of 120 mph. A slight shift to the south on landfall would send a 9 to 12-foot storm surge up the bay. Anyone who was around during Tropical Storm Isabel knows well what a surge like that can do in downtown Baltimore, Fells Point and the western shore of the bay.

But Isabel was a tropical storm by the time it went ashore in North Carolina and came north into Maryland. The National Hurricane Center knows of only two storms that have made landfall in Maryland at hurricane force. A blast like Zoe would cause huge havoc. Downed trees throughout Southern Maryland and the Eastern Shore. Power outages. Loss of potable water supplies. Mandatory evacuations of several hundred thousand people.

Chris Strong, the warning coordination meteorologist at the NWS Sterling office, told me that such a storm as Zoe, while unprecedented, is not impossible. He recalled Felix, in 1995, which made a bee-line for the Chesapeake, but stalled offshore, wobbled around a bit, then finally drifted away.

Next time we may not be so lucky.

Posted by Frank Roylance at 5:20 PM | | Comments (0)
Categories: Cool pictures

May 5, 2008

Off to a great start


The high pressure system that began sweeping in Sunday behind that cold front looks like it will dominate our weather for the better part of this week. Forecasters are calling for sunny to mostly sunny skies through Wednesday, with highs in the 70s to near 80 degrees by Wednesday. That's a little warmer than normal for this time of year in Baltimore. Beautiful.

(There is a deck of low clouds, visible on the NOAA satellite image above) skidding through the region ATM, but the folks out in Sterling say that will move along, and thin as drier air continues to move in. Things will be drier and clearer Tuesday through Thursday.)

But as the week rolls along, another low-pressure system, described as "potent" and "tighly wrapped" is expected to develop over the Central Plains states. If so, we can expect the danger of intense storms and tornadoes to develop in Tornado Alley again, as they did last week. None of this is unusual in springtime.

That low will move gradually west to east, into the Ohio Valley, weaking before it heads our way with a chance of showers Thursday into Friday.

Happily, high pressure returns after the storm blows through, bringing us sunny skies and cooler temperatures for Saturday, if the forecast holds up. Showers return on Sunday as yet another low approaches from the Plains.

For stargazers, the dry air working its way into the region today will bring clear skies tonight. My Clear Sky Alarm  went off this morning, showing good stargazing conditions after 11 p.m. tonight, although temperatures will also be dropping - into the mid-40s for Baltimore. The record low for Baltimore on a May 6 is 40 degrees, reached last in 1925.

So, enjoy the clear skies for a while, then jump into a warm bed.

Posted by Frank Roylance at 11:16 AM | | Comments (0)
Categories: Forecasts

Cool eclipse in a frigid place


                                                                                       Fred Bruenjes - used with permission

Some people will go anywhere to watch a total eclipse of the sun, even to the bottom of the world. The image above was shot Fred Bruenjes, of the Moonglow Observatory, during the Nov, 23, 2003 eclipse in Antarctica.  

Here's more.

The next total solar eclipse that will be visible from the continental U.S. is now just over nine years away, in 2017. Here's more on that one.

Posted by Frank Roylance at 11:03 AM | | Comments (1)
Categories: Cool pictures

May 2, 2008

Get outside Saturday

Sure, we're looking at another weekend of showers and thunderstorms. But forecasters say the next cold front won't get here until Sunday. Saturday should start out just fine, with a high in the mid-70s and at least partly sunny skies. The showers and thunderstorms aren't due until Saturday night, after 9 p.m..

Today looks even better. Got the day off? Good for you. Too bad for me. You can expect highs topping 80 degrees in the Baltimore area, with plenty of sunshine.

For me, it's highs (and lows) around 75 degrees, with plenty of fluorescent light. If we ever get our Sun weather station data online (after 21 months of pleading; Send help!), you'll be able to click to monitor the temperature and humidity - on my desk in the Sun newsroom, as well as all the conditions outside on the Big Shots' parking lot. What fun, right?  Actually, it would be one of the more detailed and accurate data points for downtown Baltimore.

So how are we doing on the drought front? No change from last week, according to the Drought Monitor map released yesterday. Have a look here. Folks on the lower Eastern Shore are still looking at dry to moderate drought conditions. Northern and Central parts of the state are doing just fine.

The Baltimore Department of Public Works reports today that the three reservoirs serving the city's water customers are now at 92 percent of capacity. Loch Raven is full; Prettyboy stands at 92 percent of capacity, and Liberty is at 89 percent. And there's more rain due.

Here's the radar image showing the big low swirling counter-clockwise in the middle of the county. The arc of clouds sweeping off the southeast of the center of the low is the stormy cold front that kicked up tornadoes yesterday in Oklahoma. Very cool video here.

The same front will bring us the clouds and rain on Sunday. North and west of the low, the storm dropped some May Day snow in Colorado. Here's a video clip.



Posted by Frank Roylance at 11:07 AM | | Comments (0)
Categories: Forecasts
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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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