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March 26, 2010

Gone fishin'

FishingNow that the danger of snow seems to have (mostly) passed, and with the trees in bud, your old WeatherBlogger will be taking a few days off to enjoy the weather, recharge his batteries, and get to know his favorite teacher again.

You should do the same. Get some sunshine; rake up winter's mess; and take time to look at the stars.

Back in a bit. Cheers. 

(SUN PHOTO/Algerina Perna, 2009)


Posted by Frank Roylance at 6:23 PM | | Comments (1)
Categories: Notes to readers

Rain ending, but temperatures on the skids

The quarter-inch of rain that fell overnight at BWI-Marshall (nearly a half-inch here at The Sun) is drawing to an end. But the cold front that triggered the precipitation has also dropped Rainy day in Padoniatemperatures 30 degrees from their 72-degree high on Thursday.

North winds out of Canada, drawn south around the western side of the rain-making low-pressure system now moving off the Virginia coast, will keep temperatures low today. NWS forecasters out at Sterling say BWI-Marshall will get no higher than 46 degrees today. That's 10 degrees or so below the long-term average for the date.

And as skies clear overnight, radiational cooling will allow the readings to fall deep into the 20s, a hard freeze. The forecast low for BWI is 25 degrees. The record low for the date in Baltimore is 20 degrees, last reached in 2001. The average low is 37 degrees. Higher elevations in western Maryland could see lows in the teens.

The payoff will be in the form of sunny skies on Saturday, although temperatures will rise only into the 40s, if the forecast holds. There is a risk of more showers Sunday, lingering into Monday as another cold front passes by. But from there things begin to improve. Sunshine returns Tuesday, and daytimes highs begin to climb gradually back above the norms and into the 60s.

(SUN PHOTO/Frank D. Roylance)

Posted by Frank Roylance at 10:48 AM | | Comments (1)
Categories: Forecasts

March 25, 2010

Aussies suffer another costly hailstorm

The National Weather Service's Sterling forecast office recorded its first (non-snow) thunderstorms of the year on Monday, and with them came some 1-inch hail.

But that hail pales in comparison with the storms that have pounded parts of Australia during March, as the southern continent transitions from summer to fall. Hailstones as big as 4 inches have been documented in these storms. The damage has been tremendous.

Steve Zubrick, science officer at Sterling, cites newspaper sources down under who quote the Insurance Council of Australia saying insurers there have already received 79,000 claims worth $491 million. But insurance experts believe the total will exceed $700 million and set a new record for the country.

Zubrick tells me the first storm struck March 6 in Melbourne, with stones likened to lemons, near 4 inches in diameter. Another occurred in Perth, in Western Australia on Monday, March 22. Both came with flash flooding, as this video from Melbourne makes plain.


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

March 24, 2010

April nears and we're still melting

We've got flowers, and buds and bugs. The sidewalk tables are set again, and it sure feels like winter is over. But the snows of February (and December) are still with us, here and there, at least Snow pile, BWI, March 24, 2010where they were plowed and dumped into huge piles.

Here's one of them. The photo was taken Tuesday afternoon out at Baltimore-Washington International Thurgood Marshall Airport, and sent to me Wednesday by alert reader Jonathan Dean. Looks like the snow had been plowed off the adjacent garage. Dean said:

"There are still a couple of large snow piles remaining here at BWI ... including this one behind the airport's hourly garage.

"There's also a pile of ugly, dirty snow remaining on the airfield, on the helipad alongside the general aviation runway 15L-33R. We pushed a large pile of snow there during the storms, and it continues to melt away."

Posted by Frank Roylance at 11:35 AM | | Comments (2)
Categories: Cool pictures

More rain due, but weekend looks sunny and cool

Looks like we're set up for another delightful early spring day here in Central Maryland. The NWS has us scheduled for plenty of sunshine, with forecast highs in the mid-60s Wednesday and most of Thursday. That's still 5 to 10 degrees above the averages for the date.

The fine weather comes to us courtesy of high pressure building now into the mid-Atlantic. It arrives with brisk NW winds, which could reach 15 to 25 mph later today. With clear skies Wednesday night into Thursday, we'll have lots of stars and planets to look at, but temperatures will drop below 40 in some places.

Thursday looks almost as good, but clouds may move in later in the day as a cold front and an attendant low pressure center approach. Forecasters expect rain by Thursday night, with a half- to three-quarters of an inch possible by Friday morning.

Spring bulbsMost of that rain should leave us by later in the day Friday, setting us up for a return of high pressure and sunshine for the weekend. But temperatures behind the front will feel much cooler. The low Friday morning may drop well below freezing, and the weekend highs will only be in 50s, below or just barely reaching the norms for the dates.

That's the forecast from the NWS. Now here's something for the number crunchers among us:

One year ago, on March 28, 2009, I wrote a Page 1 story for The Baltimore Sun headlined: "Parched state: Half of Md. in a drought with 2009 off to a dry start." The US Geological Survey had just issued a press release on the emerging drought, and the dry weather that had persisted through the fall and winter.

The lead paragraph on the story said, "Marylanders may see some welcome rain this weekend, but it's not expected to fully reverse what has become the driest start to a calendar year in 138 years of record-keeping in Baltimore."

Well, that story killed the drought, and the weekend rain marked the end of the dry weather. April 2009 was the wettest in 16 years. In the 12 months since the story ran, Baltimore has seen just three months of below-average precipitation - in July, September and January. The shortage in those months totaled just 2.29 inches.

In the other nine months since April 1, 2009, we have enjoyed (except, maybe, when it fell as snow) abundant surpluses totaling 22.5 inches - nearly 10 times the total deficit. The wettest month was last May, with 8.42 inches, more than 4.5 inches above average for that month. December, with 8.06 inches in melted precipitation, was the wettest and snowiest December on record for the city, and the wettest winter month.

Here are the precipitation totals at BWI-Marshall, and the surplus (or deficit):

April 2009:  5.80 inches  +2.80 inches

May 2009:  8.42 inches  +4.53 inches

June 2009:  5.52 inches  +2.09 inches

July 2009:  3.29 inches  (-0.56 inch)

August 2009:  4.76 inches  +1.02 inches

Sept. 2009:  3.48 inches  (-0.50 inch)

Oct. 2009:  6.24 inches  +3.08 inches

Nov. 2009:  4.94 inches  + 1.82 inches

Dec. 2009:  8.06 inches  +4.71 inches

Jan. 2010:  2.24 inches  (-1.23 inches)

Feb. 2010:  4.15 inches  +1.13 inches

March 2010:  4.29 inches  +1.32 inches*

TOTAL:  61.21 inches  +20.21 inches

* Through March 23; more rain is forecast

(SUN PHOTO/Frank Roylance)

Posted by Frank Roylance at 10:31 AM | | Comments (0)
Categories: Forecasts

March 23, 2010

Mercury coming into view after sunset

Some accounts say Copernicus (painting), the guy who worked out the math that showed how the planets all revolve around the sun, never actually saw the planet Mercury. An article in the April edition of Sky & Telescope magazine casts doubt on that notion.

But it's very true that Mercury is the most difficult of the five naked-eye planets (six, if you countNicolaus Copernicus Earth) to see.

That's because, as the nearest planet to the sun, it never wanders far from the sun's glare for observers on Earth. It becomes visible only at the extremes of its orbit, on one side of the sun or the other. That places it in our view every few months, low in the east just before sunrise, or low in the west just after sunset. Sometimes it's easier to see than other times, depending on the geometry.

Whenever skies clear in the next three weeks or so, we'll have our best chance in 2010 to see Mercury - which we rarely name without the adjective "elusive"  in front.

Look first for Venus, low in the west, about 30 minutes after sunset. It is both nearer to Earth than Mercury, and bigger. That makes it much brighter in the sun's reflected light. Venus has only recently returned to the evening sky. It will get brighter each night as it rises out of the sun's glare.

Mercury/MessengerYou should find Mercury just to the right of Venus, and a bit below. Binoculars will help, but if skies are clear and dark enough, it should pop into view without magnification. The two planets will appear closest together - the width of three fingers held at arm's length - on April 3 and 4.

The relative positions of the two planets will change each night as Mercury rises, turns, then falls back toward the sun as it races along its orbit. By mid-April, Mercury will be much dimmer and falling fast into the sunset, while Venus continues to climb.

With patience and persistence, you'll find it. Copernicus did.

(PHOTO/Mercury/Messenger mission)

Posted by Frank Roylance at 2:41 PM | | Comments (0)
Categories: Sky Watching

March 22, 2010

A chance for thunder later today

Not counting thundersnow, this forecast would be the first this year for thunderstorms in Central Maryland. And a bit of flash and bang might spice up what is otherwise a pretty dreary day.

We've recorded 0.27 inch of rain so far here at The Sun. Showers and thunderstorms are in the NOAAforecast right into Tuesday as a low-pressure system drifts over our heads today and tonight. Once it gets past us, high pressure will begin to move in and dry things out. But we may not see the benefits - in sunshine - until late Tuesday and Wednesday.

The heavier showers and thunderstorms - if they develop later today - should be brief. But they could drop a quarter-inch of rain or more on isolated locations.

Behind the storms, we'll see a cold front pass by tonight, and with it will come drier air. Out in the western counties, above 3,000 feet or so, they could see some snow showers.

There's sunshine on tap for Wednesday and Tursday, with highs still 10 degrees above the seasonal norms, in the low- to mid-60s. By week's end, though, we're looking at more showers and cooler temperatures, in the 50s.

Posted by Frank Roylance at 12:13 PM | | Comments (0)
Categories: Forecasts

March 19, 2010

Nice weather should hold through Sunday

Unless the folks at Sterling miss their bet, this fabulous March weather should hold through the weekend. The forecast calls for highs near 70 degrees, with plenty of sunshine as we enjoy the Snow pile in Padoniareturn flow out of the southwest, behind the departing high pressure system.

By Sunday night, though, we're looking at increasing chances for rain as we come under the influence of the storm that was dropping snow on the Colorado Rockies today.

The rain showers will start sometime after midnight, and continue through Monday and Tuesday, as the storm passes to our south, with daytime temperatures sinking into the 50s and low 60s behind a cold front.

But then the sunshine returns for a few days next week. Temperatures will be about 10 degrees cooler than we're seeing this week, but still above the norms for this time of year in Baltimore.

Still, even as the spring equinox arrives at 1:33 p.m. EDT on Saturday, the snows of February hang on. Here's a pile off Old Padonia Road in Baltimore County. The photo was taken Friday morning.

(SUN PHOTO/ Frank D. Roylance)

Posted by Frank Roylance at 4:11 PM | | Comments (0)
Categories: Forecasts

Two chances to watch Int'l Space Station

Stargazers will get two opportunities in the coming days (or rather, nights) to watch the International Space Station fly across Baltimore's skies. Both are very bight evening passes, high over head, with plenty of other stuff in the sky to add variety to your time under the stars.

The weather looks pretty good for Saturday night, but Monday evening could be dicey, with "mostly cloudy" skies forecast. Check for weather updates. Urban lighting and thin clouds shouldn't hurt any. The ISS is very bright on these passes.

The first event comes Saturday evening, as the station passes over Lake Michigan and becomes visible from Central Maryland. Look for a very bright, star-like object rising in the northwest at 8:12 p.m. EDT. If it's blinking, has multiple or colored lights, it's an airplane. Keep looking. 

The ISS and its crew will climb high overhead, passing just above the moon in the western sky. It will climb as high as 69 degrees - more than two-thirds of the distance between the southwestern horizon and the zenith (straight up) by 8:15 p.m.

NASAFrom there, the station will pass below the planet Mars in the southeast, disappearing over the Atlantic at 8:17 p.m.

The second pass comes on Monday evening, and it will look very much like Saturday's flyby. The station will rise in the northwest again, this time at 7:26 p.m. EDT. It will pass below the moon, 65 degrees above the southwestern horizon at 7:29 p.m.

From there it will slide off toward the southeast, passing between Mars and Sirius, the bright star to the lower left of the Constellation Orion, before vanishing at about 7:31 p.m. As always, drop back here after the show and share the experience.

Posted by Frank Roylance at 7:48 AM | | Comments (4)
Categories: Sky Watching

March 18, 2010

How sweet it is; BWI reaches 70 degrees

This must be our reward for battling back from the snowy purgatory we found ourselves in last month - a gorgeous, cloud-free day with temperatures in the deliciously perfect upper 60s and low 70s. 

The mercury out at BWI-Marshall Airport reached 70 degrees at 3:15 p.m. Thursday. It was the March sunshine in Baltimorefirst time we've seen the 70s there since Nov. 15, when we touched 72 degrees

The Washington airports were in the same ballpark: 69 at Dulles at 3:59 p.m., and 71 down at Reagan National at 3:04, according to the NWS forecast office in Sterling, Va.

Here at The Sun, we reached 71 degrees at 3:30 p.m. It was 70 at the Maryland Science Center.

So, with spring officially less than 48 hours away, have we finally rid ourselves of all the February snow piles out there? The one behind my house has finally vanished. How about yours? How are the mall parking lot piles doing? Any more guesses on when the last of February's snows will finally trickle away?

(SUN PHOTO/Perry Thorsvik 1998)

Posted by Frank Roylance at 6:08 PM | | Comments (2)
Categories: By the numbers

March 17, 2010

Stowaway on space shuttle likely perished

NASA says its ground crews discovered an apparent stowawayNASA STS 119 on the space shuttle Discovery (STS-119) before its launch on March 15, 2009. It was hoped the intruder would leave before the rockets ignited. But that didn't happen, and the hitchhiker is NASA free tail bat on shuttle tankthought to have died during liftoff.

The stowaway was probably a free-tail bat. It was spotted clinging to the surface of the shuttle's orange external fuel tank. Observers saw it moving around a bit, and they expected it would fly off before the countdown reached zero.

But it didn't, and it was seen on the tank as it began to rise toward orbit. NASA officials figure it was torn off the tank by wind during ascent and incinerated in the shuttle's rocket exhaust.

The bat may have had an injured wing. Here's more.

Posted by Frank Roylance at 4:35 PM | | Comments (1)
Categories: Cool pictures

February was cool here, warm globally


The National Oceanic and Atmospheric Administration has published its global and national data for February and for the past winter months. It demonstrates as clearly as anything could that what's happening locally, even nationally, does not necessarily reflect the global trends that we all need to be concerned about.

In the contiguous United States, February was cool, averaging 2.2 degrees below the long-term average.  Nearly two-thirds of the nation experienced below-normal temperatures. The averages were much below normal in the southeast, the Plains and mid-Atlantic states. Baltimore, Washington, Philadelphia, Pittsburgh, New York's Central Park and Wilmington, Del. all had their snowiest winters ever.

Florida had its fourth-coldest February since records began in the 19th century, and Louisiana had its fifth-coldest. On the other hand, Maine had its third-warmest winter on record. It was also warmer than average in the Northwest.

It was also a warm February - and a warm winter globally, according to NOAA. The combined global land and ocean surface temperature for February was the sixth warmest on record. The global land surface temperature alone for the month was tied with 1994 as the 14th warmest.

While it was unusually cold in the U.S., Mexico, Europe and Russia, most of the rest of the globe's land masses were warmer than average in February, especially Alaska, Canada, the Middle East and North Africa.

The winter as a whole was the fifth-warmest on record globally, just over one degree warmer than the 20th century average, NOAA said. Land temperatures were the 13th warmest on record.Australian drought

While the United Kingdom had its coolest winter since 1978-79, much of Australia was warmer than normal. Western Australia, where drought has been a problem (photo), saw its warmest December through February period (summer) on record.

The Arctic saw its 12th consecutive February with below-average sea ice extent. February arctic sea ice has declined by 2.9 percent per decade since 1979. At the same time, on the other end of the planet, Antarctic sea ice has been expanding. The southern continent saw its eighth-largest February sea ice extent on record. It has increased by 3.1 percent per decade since the '70s.

Across the Northern Hemisphere, snow cover in February was the third-largest on record, after 1978 and 1972. For the winter, it was the second-largest snowcover on record. For North America alone, it was the largest, NOAA said. 

Posted by Frank Roylance at 11:41 AM | | Comments (4)
Categories: Climate change

Perfect through weekend, then back to reality

It would be hard to beat the weather forecast for the next few days, and straight on through the weekend. High pressure dominates the eastern half of the nation. Skies will be clear, and sunshine will drive temperatures through the mid- to upper-60s by Thursday and into the low 70s (!) on Saturday.

CrocusesBut the official arrival of spring on Saturday won't mean this kind of weather is here to stay. Forecasters say there's a cold front due to barrel through late on Sunday. That could bring thundershowers, and it seems certain to cancel the warmth we're enjoying now, especially for the snow-weary western counties.

The forecast calls for highs only in the 50s at BWI-Marshall on Monday and Tuesday, after the cold front blows through. The overnight lows will drop to near freezing again. That's actually about normal for this time of year in Baltimore. But after this week it's going to seem like a relapse into winter.

That will be especially true out in Garrett and Allegany counties. Westerly winds behind the front will mean upslope snow showers Monday and Monday night. Like they need more flakes to add to the 250 inches or more they've seen this winter.

This backsliding comes to us courtesy of the blocking features over the North Atlantic that controlled our weather for much of the winter. That Arctic high was responsible for the twist in the northern jet stream that kept the door to the eastern states open to cold Canadian air, and turned the parade of El Nino-fueled storms off the Pacific into snow-makers.

Eric the Red, a professional meteorologist in Baltimore, says that blocking high is back.

"You see, it's like Friday the 13th. You can't really kill Jason. And until further notice, you can't really kill the northern-Atlantic blocking high ... You don't have to be a meteorologist to see that bad things are coming our way. There's an initial surge of cold air over the nation's midsection, with another even-colder shot dropping out of Canada ... D'oh.

"I'm holding out hope that the switch back to cold doesn't last, but it's a little too early to say. Upper air forecast charts kinda imply the chilly weather might be back for a while."Spring peeper, Oregon Ridge, Md.

That doesn't necessaily mean more snow. Heck, I heard my first spring peepers (photo) last night from the WeatherDeck in Cockeysville, even as the last basketball-sized pile of snow melted in the back yard.

But snow - even big snow - can happen in March in Baltimore. Steve Zubrick and Jared Klein, out at the NWS forecast office in Sterling, have been looking at the stats from the memorable (if you're old enough) winter of 1957-58.

They noted that the Arctic Oscillation - the same blocking high mechanism Eric the Red is talking about - was in a similar (negative) phase back then. In February 1958, Central Maryland was clobbered with a 15-inch storm, which until this winter ranked 9th on the all-time Top 20 snowstorm list. A month later, on March 19-20, the region was buried by a wet snowfall that topped 30 inches in Mount Airy, north and west of the city. Totals dwindled to 8 inches at Friendship (now BWI-Marshall) Airport because of a mix with rain and sleet; otherwise, that snowstorm would rank among the top 20 for Baltimore, too.

That March 1958 storm crippled transportation, ripped down power and phone lines and remains one of the most disruptive storms on the record books for this area. This weekend is the 52nd anniversary of that storm.

"Nice storm, if you love heavy, wet snow!," Zubrick said. "Winter can be tough here, even in March!"

(SUN PHOTOS/Top: Virginia Williams, 2010/ Bottom: Glenn Fawcett, 2007)

Posted by Frank Roylance at 10:28 AM | | Comments (2)
Categories: Forecasts

March 16, 2010

Venison on the menu in Ashland


Nothing like a fine breakfast with a group of close friends. These vultures gathered this morning to dine beside Western Run on the carcass of a whitetail deer (barely visible, far left). The animal appeared to have been struck by a car on Ashland Road, then stumbled, or was dragged, to the edge of the woods.

The forecast calls for more sunshine today, and through the end of the week, with temperatures rising well into the 60s as the week rolls along.  

(SUN PHOTO: Frank Roylance, 3/16/10)

Posted by Frank Roylance at 9:56 AM | | Comments (1)
Categories: Cool pictures

March 15, 2010

Four storms ranked among top 30 Northeast snows

Four of the big snowstorms that struck the Northeastern United States this winter have been ranked among the 30 highest-impact snowstorms of the last 54 years.

The assessments are made by the National Climatic Data Center. Meteorologists there use a ranking system developed to weigh not just the snow depth at any one location, but the depth, the geographic NCDC snow map area and the population it affected over its full range.

Called the Northeast Snowfall Impact Scale (NESIS), the system was developed in 2004 by Paul Kocin and Louis Uccellini, of the National Weather Service. It's since been applied retrospectively to every major storm since 1956, and to all the big Northeast snowstorms that have occurred since the scale was developed.

The NESIS scale calculations generate an index number, which is translated into a five-level Category ranking similar to the Saffir-Simpson Hurricane Scale, including Notable, Significant, Major Crippling and Extreme. 

CategoryNESIS ValueDescription

Only two storms have been ranked as Cat. 5 "Extreme." They were the March 12-14, 1993 storm, which was given a NESIS number of 13.20; and the Jan. 6-8, 1996 storm, rated at 11.78.

Here, for comparison, with their preliminary rankings and NESIS numbers, are this winter's four biggest snowstorms. Only the three earliest had a major impact in Baltimore. And here's a link to the full list.

17. Feb. 23-29, 2010: 5.11, a Cat. 3 "Major" storm.

21. Feb. 4-7, 2010:  4.30, a Cat. 3 "Major" storm. (Map above.)

25.  Dec. 18-21, 2009:  4.03, a Cat. 3 "Major" storm.

26:  Feb. 9-11, 2010:  3.93, a Cat. 2 "Significant" storm.

Posted by Frank Roylance at 4:49 PM | | Comments (1)
Categories: By the numbers

Hang in there; sunny and 60s by Wednesday

There was more rain on our parade this morning as the departing huge weekend storm continued to spin off Delmarva and throw its weight around. But the slow-moving system is on its way out, NOAAand there is some real springtime weather in the wings.

First, the rain. Forecasters out at Sterling say we could see a few tenths of an inch more Monday and Tuesday before we finally shake free of this mess. Rivers and streams remain high, but the crests appear to have passed most points on the major rivers. 

The National Weather Service still has Coastal Flood Advisories posted until 11 p.m. Monday all around the Chesapeake Bay, with high tides expected to run 1.5 feet or more above predicted levels and minor coastal flooding possible.

Out along the Maryland beaches, the high tides will run 2 to 2.5 feet above normal, with minor flooding in Ocean City.

At Conowingo Dam, the waters of the Susquehanna River reached 22.12 feet at 9:30 a.m. Flood stage is at 23.5 feet. Minor flooding at Port Deposit, Md. begins when the river reaches 23.7 feet. The gauge at Conowingo was reporting 251,000 cubic feet per second flowing past the instruments this morning, a record for the date. 

On the tidal Potomac River, Coastal Flood Warnings are up until 11 p.m. Monday as high tides and the crest of the river flooding reaches the Washington, D.C. and Alexandria, Va. area.

The river flood crest is due in Washington around midday Monday, with Potomac River levels rising as high as 5 feet above normal at Georgetown. Major flooding is forecast at Wisconsin Avenue (chart below). More tidal flooding is expected in Old Town Alexandria


Three days of rainfall at BWI-Marshall have totaled more than 3.6 inches, but as wet as it's been, no records appear to have been broken. Saturday was the wettest day of the three, with 2.31 inches of rain at BWI. That fell short of the record for the date of 2.45 inches, set in 1993.

The total for the month of March so far, through Sunday, is 3.71 inches. The long-term average for March in Baltimore is 3.93 inches, so we're close to the month's quota, with half the month yet to go. The wettest March on record for the city is 8.64 inches, recorded in 1994.

But enough talk of rain. The sun will be out ... not tomorrow, but Wednesday if the forecast from Sterling holds up. The forecast calls for sunshine and highs in the low to mid-60s through Saturday. Showers are possible Saturday night and Sunday.

Posted by Frank Roylance at 10:53 AM | | Comments (1)
Categories: Forecasts

March 14, 2010

Howard County tops rain charts

Elkridge and several other communities in Howard and Anne Arundel counties topped the charts for rain totals in Maryland for the 48 hours ending Sunday morning. The two-day total at Elkridge was 4.15 inches.

BWI-Marshall Airport reported 0.98 inch on Friday, another 2.31 inches on Saturday, and 0.29 so far on Sunday, for a three-day total of 3.58 inches. The average monthly rainfall for a March at BWI-Marshall is 3.93 inches.

Here on the WeatherDeck in Cockeysville, we have 1.98 inches on the gauge since Friday. The Sun's weather station at Calvert and Centre streets shows 2.34 inches since Friday.

Here are some other totals for the two days of rain, compiled from CoCoRaHS:

Elkridge, Howard County:  4.15 inchesNOAA AHPS

Severn, Anne Arundel:  3.79 inches

Ellicott City, Howard:  2.86 inches

Elkton, Cecil:  2.74 inches 

Towson, Baltimore Co.:  2.70 inches

Columbia, Howard:  2.65 inches

Severna Park, Anne Arundel:  2.49 inches 

The National Weather Service has been reporting flooded roads in Elkridge, Thurmont and in Towson over the last 24 hours. The Potomac is in moderate flood at Paw Paw, W.Va., Point of Rocks, Md. (see chart), and at Wisconsin Avenue in Washington, D.C. Minor flooding is reported on Antietam Creek at Sharpsburg, and Harper's Ferry and Little Falls on the Potomac.

Posted by Frank Roylance at 12:02 PM | | Comments (0)
Categories: By the numbers

March 13, 2010

Flooding increases amid heavy rains


Heavy, peristent rain across the region is bringing small stream and creeks to their brims, while waters are rising to flood stage along the Potomac River, the Monocacy in Frederick County and other rivers.

BWI-Marshall has tallied more than 3 inches of rain so far from this storm. We have 1.6 on the gauge here on the WeatherDeck. Drop a comment and let us know what you're seeing.

The National Weather Service has posted Flood Warnings from Garrett County east to theWestern Run in flood Chesapeake, with more rain expected. Here is a bit of this afternoon's Forecast Discussion from Sterling:




NOAA's Advanced Hydrologic Prediction Service is reporting minor flooding along the Potomac River near Williamsport, Little Falls (chart above) and Wisconsin Avenue in Washington, D.C.

The National Weather Service is also reporting flooding and closed roads on Route 77 near Cunningham Falls, near Thurmont in Frederick County and in Elkridge. Roads have been closed, also, in parts of Loudon County, Va., and Hampshire County, West Virginia.

(SUN PHOTO: Frank D. Roylance)

Posted by Frank Roylance at 2:51 PM | | Comments (2)
Categories: Flooding

Arundel sees most rain overnight

This storm isn't over yet, but rain tallies overnight show that Anne Arundel County has received most of the rain so far. The only station reporting totals higher than Arundel's this morning was Thurmont, with 1.75 inches by 8 a.m. The totals were gathered by CoCoRaHS.

Also, the flood gauges so far show most rivers and streams in Maryland have not yet reached flood stage, although much of the runoff is not expected to reach the larger rivers until late today or tomorrow. You can follow the river flooding here. The chart below shows that water levels on the Potomac at Wisconsin Avenue in Washington have already climbed within a few inches of flood stage.

Here are some samples of the rain totals reported by this morning. The differences across the region are sharp. Where northern Arundel reported well over an inch, Towson saw barely a half-inch. Here on the WeatherDeck in Cockeysville, we've recorded less than three-quarters of an inch. NWS forecasters seem to be dialing back on their more dire rain forecasts of Friday afternoon.

Thurmont, Frederick Co.:  1.75 inchesNOAA Wisconsin Ave. flood gauge

Severn, Anne Arundel:  1.68 inches  

Severna Park, Arundel:  1.29 inches

Leonardtown, St. Mary's:  1.11 inches

Salisbury, Wicomico:  1.01 inches

Ellicott City, Howard:  0.94 inch

Columbia, Howard:  .81 inch

Sykesville, Howard:  0.66 inch

Towson, Baltimore Co.:  0.59 inch

In the meantime, Flood Warnings have been posted for Garrett, Allegany and Frederick Counties as snowmelt and rain push small streams and creeks over their banks. Waters are expected to continue to rise into Sunday.

UPDATE 11 a.m.: Flood Warnings have been extended to Baltimore County and City, northern Anne Arundel County, Howard and Carroll counties.

Posted by Frank Roylance at 8:53 AM | | Comments (0)
Categories: By the numbers

March 12, 2010

Wind and tides trigger Coastal Flood Advisories

The National Weather Service has hoisted Coastal Flood Advisories (light green on map) for Maryland's Western Shore as the coastal storm developing to our south drives water into the tidal creeks and beaches.

The advisories are in effect from Harford County south to St. Mary's, from midnight until 6 a.m. NWS/NOAAThey will then upgrade to a Costal Flood Watch, in effect through Saturday afternoon.

High tides could rise two feet above predictions overnight due in part to the persistent east winds, and in part because of increased tidal levels related to the approach of the new moon. Minor flooding is expected. Higher tides are expected on Saturday. Here's more from the NWS: 




Next high tides:

HAVRE DE GRACE: 8:17 p.m. and 8:00 a.m.
FORT MCHENRY BALTIMORE: 4:47 a.m. and 5:39 p.m.

ANNAPOLIS U.S. NAVAL ACADEMY: 3:17 a.m. and 4:08 p.m.
SOLOMONS ISLAND: 12:09 a.m. and 1:00 p.m.
POINT LOOKOUT: 11:19 p.m. and 12:10 p.m.

NOAA Tides Online

High tides, big surf and high winds are also forecast for Maryland's ocean beaches. Here's more.
Posted by Frank Roylance at 8:37 PM | | Comments (0)
Categories: Watches and warnings

Rain could total 2 to 4 inches through Saturday

The two-thirds-of-an-inch the airport has recorded will be just a drop in the bucket by Monday if forecasters at the National Weather Service are correct in their predictions for the late-winter rainstorm headed our way.Beaver Run overflows

There are Flood Watches posted for the entire state today through Saturday evening. Forecasters say the heaviest rain is due Friday night and Saturday, with 2 to 4 inches possible by the time things begin to taper off on Monday.

That much rain, coming on top of a heavy snow meltdown that has saturated the soil and kept the creeks full, will mean flooding for small creeks, streams and urban areas this weekend. And when all that reaches the larger rivers, we should expect those waters to spill over their banks, as well. You can track the flooding here.

The Flood Watches for the Eastern Shore call for even more rain - 3 to 5 inches. That's one to two months worth of normal rainfall in just four days. Do not attempt to drive through flooded roadways.

Here's's take on the rain, with their rainfall forecast map. And here is Mr. Foot's Forecast.

NOAAThe wet weather is being brought to you by a slow-moving low-pressure system that has been dawdling our over the Central Plains. The counter-clockwise circulation around that low has been dragging warm, moist air off the Gulf and the Atlantic, and delivering about 0.66 inch of rain at BWI-Marshall overnight.

Next up: A secondary low now forming over the southeast coast. The counter-clockwise circulation around that coastal low will begin to throw onshore easterly winds across Delmarva from the Atlantic. By tonight and Saturday, the rains will become heavy at times, delivering the bulk of the weekend rainfall.

The whole mess will be slow to pull away, so we can expect the drip to continue through Sunday and into Monday. We should get back to sunny skies and mild temperatures by mid-week.


Posted by Frank Roylance at 10:49 AM | | Comments (2)
Categories: Forecasts

March 11, 2010

Baltimore was 5th snowiest U.S. city

After spending a brief period at the top of the snow pile, it looks like Baltimore sledded to 5th position by the season's end in the competition for the title of "Snowiest U.S. City 2009-10."

Here are the top 10 finishers, according to a Web site called Golden Snow Globe. No idea who they are, so I can't vouch for their numbers. I know the total listed for Baltimore (80.4 inches) is no longer valid. The National Weather Service forecast office at Sterling, Va. has recalculated and cut the official total for BWI-Marshall Airport to 77 inches. That pushed Mobtown to 5th place, instead of 4th as listed on the site.

Inner Harbor in snowHere's now it should look:

1. Syracuse, N.Y.: 106 inches 

2. Erie, Pa.:  90.9 inches

3. Rochester, N.Y.:  89.6 inches

4. Philadelphia, Pa.:  78.7 inches

5. Baltimore, Md.:  77 inches

6. Pittsburgh, Pa.:  76.9 inches

7. Buffalo, N.Y.:  74.1 inches

8. GrandRapids, Mich.:  70.2 inches

9. Fort Collins, Colo.:  69.6 inches

10. Lakewood, Colo.:   68.2 inches

(SUN PHOTO: Algerina Perna)

Posted by Frank Roylance at 4:53 PM | | Comments (7)
Categories: By the numbers

Mild temperatures, heavy rain, threaten flooding

You knew this couldn't last. We've had three days in a row, now, with highs in the 60s. That hasn't happened here since last Nov. 8-10.

But sunny days in the 60s will give way this weekend to four days in the 50s, with rain. And, for the western counties, especially, the mild temperatures and rain will combine to melt down the snowpack that remains on the ground there. Forecasters say small stream and creeks will likely overflow their banks, and river flooding could follow.

The National Weather Service has already issued Flood Warnings for portions of West Virginia southwest of Maryland's Garrett County. There are Flood Watches up from Garrett east to Washington County, including the cities of Cumberland and Hagerstown, where as much as 4 inches of rain could fall through Saturday.

East of the mountains, there are Hazardous Weather Outlooks posted as far as Carroll, Howard and Montgomery counties.

UPDATE: 6 p.m.: Flood watches are now posted for all Maryland counties west of the bay, plus the Upper Eastern Shore

For Baltimore, the rain is forecast to begin late Thursday night into Friday, with more than an inch expected by early Saturday morning. The rain could be heavy at times late Friday and Saturday, with another two inches possible. Rain chances continue into Monday, so it appears the weekend will be a washout. But at least it's not snow. And our snow cover is gone, except for some lingering piles. So we won't have to add that water to the runoff. The rain will be quite enough, thank you.


Needless to say, though, we'll need to be on the lookout for wet basements, leaks through ice-damaged roofs and gutters, overflowing creeks and street flooding. And that can collapse roads, as this amazing video from Freeport, Maine demonstrates.

Never drive through flooded low spots. It's amazing how little water it takes to float a car and carry it downstream. I suspect we will be reading about water rescues, anyway, this weekend.

All this rain is approaching as a low-pressure system moves very slowly toward us out of the Midwest. The counter-clockwise flow around the low is drawing mild, wet air north from the Gulf and, eventually, the Atlantic.

The heaviest rain will arrive late Friday and Saturday. Here's a bit of this morning's forecast discussion from Sterling:


The chances for rain will continue into Monday as the storm makes its leisurely exit.

Posted by Frank Roylance at 10:49 AM | | Comments (2)
Categories: Forecasts

March 10, 2010 A busier hurricane season ahead's hurricane forecasters believe the 2010 Atlantic season will be "much more active" than last year's relatively meek performance. A rapidly weakening El Nino event in the tropical Pacific, unusually warm surface waters in the Atlantic's key hurricane nursery, weakening trade winds and higher humidities, they said, are all pointing to increased activity.

"This year has the chance to be an extreme season," said forecaster Joe Bastardi, who led the company's hurricane forecast team. He also correctly forecasted a very snowy winter season for the mid-Hurricane Bonnie in Ocean City, Md.Atlantic states in 2009-2010, although his predictions were far short of the actual, record-breaking totals.

The new hurricane forecast, out Wednesday morning, calls for 16 to 18 tropical storms this season (the average is 11; last year saw just nine, and only three became hurricanes).

Of the 16 to 18 he expects, Bastardi believes 15 will occur in the western Atlantic. He predicts seven landfalls, five of them hurricanes, of which two or three will come ashore in the U.S. (about average).

Bastardi sees similarities in this year's setup to those in 1964, 1995 and 1998. In 1964, Hurricane Cleo struck near Miami as a Cat. 2 storm and killed 217 people. In 1995, Hurricane Opal struck the Florida panhandle and caused $3 billion in damages. And in 1998, Hurricane Bonnie (photo) came ashore near Wilmington, N.C. as a strong Cat. 2 storm and caused $1 billion in damage.

The hurricane season begins officially on June 1, and continues through November.

(SUN PHOTO: Karl Merton Ferron/Bonnie whips Ocean City, Md. in 1998)

Posted by Frank Roylance at 9:00 AM | | Comments (2)
Categories: Hurricanes

March 9, 2010

December snow, and season, lose 3 inches

The winter of 2009-2010 will still go down in the history books as the snowiest on record for Baltimore. But in the end it will be three inches less stupendous than we thought.

Meteorologists at the National Weather Service have just finished adjusting their snow tallies to account for measurement problems at BWI-Marshall Airport. Officially, at least - the winter delivered 77 inches, not 80.2 inches as the weather service first reported.

And the big storm in December will be recorded officially as an 18-inch snowfall, not 21.1 inches as the first reports stated. December's monthly total has been similarly reduced from 23.2 inches to 20.1 inches, according to the Baltimore-Washington Forecast Office in Sterling.

The changes don't affect any of the records broken in December. The Dec. 18-19Snow in Baltimore snowstorm remains the biggest December snow on record for Baltimore, and the month remains Baltimore's snowiest December.

And even at a mere 77 inches, it's still the snowiest winter on record for the city. The annual average for Baltimore is 18.2 inches.

The reduction in some winter snow totals was made late last week as Sterling reviewed each of the season's snowfalls to adjust for measurements that were not in compliance with the weather service's protocol.

Until the problem was discovered in the wake of the Feb. 5-6 blizzard, contract observers working for the Federal Aviation Administration were making only hourly snow measurements, and taking storm totals after the flakes stopped falling - called "snow depth" measurements.

The technique, which complies with FAA rules, is considered invalid by the NWS for climatological data, because it does not allow the snow to compact.

The weather service requires that snow measurements for climatological purposes be made one every six hours. Because of compaction, the totals are usually smaller. That's what the FAA Snow in Baltimorecontractor was supposed to have been supplying to the weather service.

So, with no six-hour data, Steve Zubrick, Sterling's science and operations officer, elected to use the FAA's snow depth data instead of the hourly measurements, because it is the most conservative solution.

He and forecaster Jared Klein combed through the data and made the changes. Some snowfalls were unaffected. Most turned out smaller. A few increased due to rounding of snow depth numbers to the nearest inch.

Here are the original and revised numbers for BWI:

December: Original:  23.2 inches  Revised:  20.1 inches

January:  Original: 7.5 inches  Revised:  6.9 inches

February:  Original: 49.5 inches  Revised:  50 inches

Season:  Original: 80.2 inches  Revised: 77 inches 

Major storm totals:

Dec. 18-19:  Original:  21.1 inches  Revised:  18.0 inches

Feb. 5-6:  Original:  24.8* inches  Revised:  25 inches  

Feb. 9-10:  19.5 inches (no change; measured properly) 

* This was the original snow depth measurement. The FAA's total from one-hour measurements was 28.8 inches. 

(SUN PHOTOS: Top: Algerina Perna/Bottom: Karl Merton Ferron)

Posted by Frank Roylance at 4:20 PM | | Comments (9)
Categories: By the numbers

March 8, 2010

Rainy forecast raises river flood worries

Enjoy the mild weather and abundant sunshine today and tomorrow. The National Weather Service says the above-normal temperatures will remain, but forecasters predict substantial rains by later this week and lingering through the weekend. And that is raising new worries about flooding, especially in Western Maryland, where there are still several feet of snow on the ground.

Last snowThe problem lies with a low-pressure system that will be organizing over the Central Plains later this week. As it crosses the continent and approaches the East Coast, it will draw southerly winds north ahead of it, and with that air comes lots of Gulf moisture.

Light rain could start falling west of the Blue Ridge as early as late Tuesday night, with more heavy rain possible later in the week east of the mountains. The NWS says: 



Here's Eric the Red on the soppy forecast. He says the storm's progress will be blocked by the same North Atlantic blocking high that helped bring us so much snow in February. This time it's rain. Lots of it:

"Tuesday looks good. Wednesday ... eh. Maybe a little light rain as a warm front tries to lift north through the region. Thursday, I'm hoping we sneak in some decent hours during the afternoon before the leading edge of rain spirals at us from the west, which models have happening in the late afternoon or evening.

"Friday ... Saturday ... and Sunday: Doh, Doh and Doh. Storm stalls over the region, maintaining periods of rain. Some models have 2 to 4 inches of rain for that three-day stretch. Maybe more? Geeesh."

(SUN PHOTO: Frank Roylance/Last snow in my front yard melted Sunday)  

Posted by Frank Roylance at 10:32 AM | | Comments (1)
Categories: Forecasts

March 5, 2010

Both February storms were blizzards at BWI

Okay, so we don't want to think about snow anymore this season. But just to tie a ribbon on the season ...

James E. Lee, meteorologist-in-charge out at the National Weather Service forecast office in Sterling, Va., says both big storms that struck the region in February will go down in the weather history books, at least preliminarily, as blizzards.

Whiteout in BaltimoreThe weather service announced soon after the Feb. 5-6 storm that blizzard conditions were recorded at BWI-Marshall Airport from approximately midnight on Feb. 6 until 5 a.m., with winds gusting to 37 mph and visibilities reduced to one-eighth of a mile in heavy snow.

Blizzard conditions occur when falling or blowing snow reduce visibilities below a quarter mile for three hours - not necessarily consecutive hours.

Today, Lee confirmed that blizzard conditions were also reported at BWI-Marshall during the Feb. 10-11 storm, at 10 a.m., 2, 3, 4 and 6 p.m.

We already know this was the snowiest winter, the snowiest February and [February was] the snowiest month on record for Baltimore. Here are a few other winter weather trivia from this meteorological winter just ended, just published in the NWS Monthly Climate Report for BWI-Marshall in February:

1. Baltimore recorded two separate, two-day, double-digit snowfalls in the same month (Feb. 5-6 and Feb. 9-10) for the first time since record-keeping for snow totals began in the 1880s.Deep snow Baltimore

2. The two big February storms dropped a combined 44.5 inches of snow at BWI in just six days. It was the most snow ever to fall for any 7-day period on record for Baltimore. The previous record weekly snowfall was 32.6 inches, in Jan. 6-12, 1996.

3. The daily 7 a.m. "climatological snow depth" - the snow measured on the ground at BWI - on Feb. 11 was 34 inches, setting a new record. The old snow-depth record was 30 inches, recorded on Jan. 18, 1957. 

4. The average snow depth for Baltimore in February was 11 inches, the highest average monthly snow depth ever recorded for the city. The previous record was 7 inches, in January 1996.

5. There was at least an inch of snow on the ground at BWI on 22 dates in February. That's the third-highest number of February days with an inch of snow or more on the ground for Baltimore. The highest number is 27 days in 1934, followed by 25 days in 1905.

6. The maximum daily temperature at BWI failed to reach 50 degrees for the entire month. That's the first time that's happened in any month since January 1977, and only the 10th time on record. Even so, February 2010 ranked as only the 22nd coldest February on record here. 

(SUN PHOTOS: TOP: Karl Merton Ferron/BOTTOM: Kenneth K. Lam)

Posted by Frank Roylance at 5:02 PM | | Comments (2)
Categories: By the numbers

Return of fair weather reveals the night sky

The National Weather Service has hoisted a string of sun and moon icons across the five-day forecast today. It's a reminder that there is plenty to see up there if we would just lift our eyes Sunny iconabove the grimy snow piles and glaring street lights.Mostly clear

The weather forecast looks pretty good, right through the middle of next week. Sterling is looking for sunny days in the 50s by this weekend, and partly cloudy to mostly clear nights.

It's an opportunity to get reacquainted with the night sky after a month of cold and snow and ice.

Venus/Hubble Space TelescopeOn the way home the other night I noticed that Venus has returned to the evening sky. It's still very low in the west, setting about an hour after the sun. And it's not yet as brilliant as it will be by the end of March, when it will set more than an hour and a half after sunset.

But it's been quite a while since we've had Venus (left, in ultraviolet) as our evening star, and it will be a welcome sight for commuters and evening dog-walkers. Late in March we'll get a chance to see Mercury rise out of the sun's glare and get pretty close to Venus prior to a nice conjunction in early April.Mars/Hubble Space Telescope

Mars (right) is fading this month, but it remains a prominent presence high in the eastern sky each evening. Look for it just below the twin stars of Gemini - Castor and Pollux. It is noticeably redder than the bright stars of the winter constellations, and hard to miss.

And in case you missed Thursday's night's flyover by the International Space Station, the ISS will make a very similar pass on Saturday evening. Thursday's appearance was notable for the station's ability to gleam right through the scattered thin clouds that ISS/NASAspread over much of the Baltimore area.

Look for the ISS again Saturday evening as it rises above the southwest horizon at 6:08 p.m. This pass will be nearly as bright as Thursday's, but probably with fewer clouds. The station will climb  even higher - to within 3 degrees of the zenith at 6:11 p.m. From there it will slide off toward the northeast, disappearing from view at 6:14 p.m.

Saturn, too, is visible in the evening sky this weekend as it nears opposition on the 22nd. Look for it low in the east southeast later in the evening, say, 10 p.m. It has a steady light and a slightly yellowish tint compared with the stars.  

Clear skies!    

Posted by Frank Roylance at 12:02 PM | | Comments (0)
Categories: Sky Watching

March 4, 2010

Bright pass by Int'l Space Station this evening

Space Cadets! If skies stay clear enough, we'll have a fine opportunity this (Thursday) evening to watch the International Space Station fly almost directly over Baltimore.

The ISS will be cruising up the East Coast around dinner time. We'll catch our first glimpse as it NASA ISSpasses 220 miles over Georgia, and we'll be able to watch it until it disappears in the Earth's shadow off the coast of Maine.

Look for a bright, star-like object rising above the southwest horizon at 6:53 p.m. If it has multiple lights, colored or blinking lights, it's an aircraft. Keep looking.

The ISS will climb toward the zenith, passing above the bright winter constellation Orion at about 6:56 p.m. From there, the station will fly above the twin stars of Gemini and - just below Gemini in the eastern sky, reddish Mars - before vanishing in the northeast at about 6:58 p.m.

As always, take the kids outside with you. They're great at spotting this thing. And then come back here and leave a report to share the experience.

Got the stargazing bug? Head out to the Community College of Baltimore County, this Friday evening for a Star Party being thrown by the school's Astronomy Dept. Here are the details:

"Star Party, from 7 to 9 p.m. at the Observatory at CCBC, 7200 Sollers Point Road. If conditions appear cloudy, rainy or snowy, please check for cancellations by calling 410 282-3092 approximately 45 minutes before the scheduled start time.

"Visit the CCBC Web site for additional information about star parties, or call 443 840-4216." The star parties are free.

Posted by Frank Roylance at 12:52 PM | | Comments (4)
Categories: Sky Watching

Can March sunshine melt the last snow pile?

All that wishing and hoping last month has finally gotten some traction. The National Weather Service is serving up almost a full week of fine late-winter (or early spring) weather for Central Maryland as stormy weather moves farther out to sea, and high pressure builds in from the northwest.

After the snowiest February on record, and one of the coldest in the last 40 years, we're looking at six straight days of sunshine ahead, with daytime highs in the 40s today and tomorrow, snapping SNow piles at BWI-Marshall Airportto 50 degrees or more through the weekend and well into next week. The average high for this time of year in Baltimore is 50 degrees. Overnight lows will rise above freezing by next week.

It's going to feel positively spring-like, except for the huge piles of snow and ice that persist on parking lots, along roadsides and in shaded spots all across the region.

We still have a small pile on our front yard, and a big one in the rear, where we threw the snow we shoveled off the WeatherDeck, and where sunshine doesn't penetrate until afternoon.Loveton Business Park 3/4/10

Kinda makes you wonder whether any of the heaps will survive until April 1. If you'd like to register a candidate snow pile, keep an eye on it this month, and report back to the WeatherBlog when it vanishes, feel free to send me a note.

Please include your name and email address, and the precise location of the heap. A picture would be fine, too. That's the Loveton Business Park in Sparks at right, sent to me by L.J. Kirk.

Let's see if we can identify the last remnant of February's storms (in the city and five surrounding counties) when it finally trickles off into history.

No prizes. Just glory for the last pile standing.

(AP PHOTO/Rob Carr at BWI-Marshall)

Posted by Frank Roylance at 10:44 AM | | Comments (3)
Categories: Forecasts

March 3, 2010

Coastal storm is kicking up the surf

The big low-pressure system riding up the east Coast today is driving northeast winds onto the mid-Atlantic beaches this Wednesday morning. The National Weather Service has posted Coastal NOAAFlood Advisories for the Maryland shore:


For a look at the surf, check out the Kite Loft web cam in Ocean City. Looks like those folks have installed a higher definition camera. First time I've seen it, but it's a much better picture than I've noticed before. Or maybe it's my imagination.

Here's a look at the surf in Rehoboth, Del. I didn't realize they were rebuilding the boardwalk out there. Is that repair work for damage earlier this winter, or routine replacement? Anybody know?

Posted by Frank Roylance at 9:54 AM | | Comments (3)
Categories: Cool pictures

March 2, 2010

Baltimore in snow, from space

The photo is more than seven years old, but still ... A snapshot of Baltimore under a new blanket of fresh snow, shot from the International Space Station as it flew 220 miles above the city? That's a cool picture in my book, even if it was shot in December 2002. Enjoy.

 Baltimore in snow, from space

Posted by Frank Roylance at 5:49 PM | | Comments (1)
Categories: Cool pictures

Snow tonight should be minimal

Although light snow has already been reported in the northern Baltimore suburbs this afternoon, Central Maryland should be spared a difficult time with the approaching storm.

The National Weather Service is predicting less than an inch of new snow at BWI tonight, after a AccuWeather.comperiod of rain this evening and a mixture of rain and snow between 10 p.m. and 1 a.m.

Most of the snow from this system will be to our south this time, as the snow map (left) shows.

Snow showers are likely after daybreak, changing to rain and snow showers later in the morning. The airport could see another half-inch of snow from that, if the forecast holds up. The mixed showers could continue into the evening as the storm departs and draws cold air in behind it.

The cold and wintry precipitation comes to us courtesy of a low forming off the Carolina coast, and a weaker system moving this way from the Ohio Valley. Late forecast model runs suggest the two storms will phase, or merge their energies a bit more than expected. That could mean the coastal storm will track nearer the beaches, bringing higher winds and heavier precip to Southern Maryland and the Eastern Shore on Wednesday.

Forecasters out at Sterling are having a hard time predicting BWI-Marshall snowfall accumulations for this one. The problem is the usual - timing, storm track and temperatures. "Light snowfall up to one inch seems possible," they say in their afternoon discussion. "But evening shift will need to monitor expected precipitation totals and temperatures in event that headlines become necessary."

One thing they do seem sure of - Garrett County will get more snow.

Wednesday night and Thursday will be windy as the storm departs to the northeast and high pressure builds from the west, forecasters say. That will eventually mean more sunshine and daytime highs stretching into the mid-50s by this weekend into early next week. It will be the first extended period of above-average temperatures since the end of January.

Student forecasters at are predicting 1 to 3 inches from DC to south centralNOAA Pennsylvania. But nudging the storm track to the west a bit, they say, "will greatly enhance snow totals."  

Eric the Red, a professional meteorologist from Baltimore, sounds a little nervous about twitches in the radar and model runs. He's holding his breath, but issued this prediction anyway:

"1 to 3 inches of wet snow north and west of town (I think the 3 might be pushing it, but what's 3 when you've had 30?), with rain possibly mixing with or changing to wet snow elsewhere with little accumulation ... maybe an inch. Weds: Periods of light rain and snow, with no additional accumulation."

I may have a new forecaster to add to the mix here. More on that if we wake up Wednesday to 3 to 6 inches of surprise snow.

Next, forecasters will be watching the snowpack in the western counties for signs of a rapid meltdown and flooding.

Posted by Frank Roylance at 4:05 PM | | Comments (1)
Categories: Forecasts

Virginia well dropped 2 feet after Chile quake

Water in a hydrological monitoring well in Christiansburg, Va. briefly dropped almost 2 feet in response to the Mag. 8.8 earthquake in Chile on Feb. 27.

The Christiansburg site is well-known to hydrologists for its sensitivity to the seismic waves that travel around the globe after major quakes. It had a similar response to the earthquake in Haiti on Jan. 12 and to others as far away as the South Pacific and the Indian Ocean.

Here's the tracing from the Chilean quake. The regular sine-wave variations are due to the effect of lunar tides on the Earth's crust:


Posted by Frank Roylance at 2:28 PM | | Comments (1)
Categories: Cool pictures

Three big snowstorms all ranked in Top 10

The National Weather Service's Sterling, Va. forecast office has disowned the list of Top 20 Snowstorms for Baltimore that was posted on its Web site for many years. In the wake of the Feb. 5-6 storm, concerns were raised about the scientific legitimacy of the criteria long used for inclusion on the list.

Jim Lee, meteorologist-in-charge at Sterling, told me that one of the problems is that the list does not discriminate among 1-day, 2-day and 3-day storms, not to mention those that seemed to rage on even longer. The No. 1 ranked snowstorm, before the list disappeared from the Sterling site, dropped snow on Baltimore over four days, from Feb. 15 to Feb. 18, 2003.

But Lee told me a few weeks back that, meteorologically speaking, no snowfall that lasts four days can be considered the consequence of a single storm. And in truth, that 2003 event really was a combination of at least two storms, with some time during those four days when no snow was falling. (The Baltimore Top 20 snowstorm list includes two others, in 1899 and 1892, that stretched over four days.)Feb. 10, 2010 snow in Baltimore

So, because climatologists only accept data on 1-, 2- or 3-day storms, the Sterling office will be reassessing its Top 20 list. What we'll probably get will be several lists, broken down by the length of the storm, and ignoring the snow that fell on the fourth day of three former Top-20 storms.

The Sterling office will also be reassessing storms that may have been measured at BWI-Marshall with hourly measurements - in accordance with FAA standards - rather than with the six-hour measurements required by NOAA for climatological purposes. That could reduce official storm totals for BWI going back as far as 1998, when the FAA took over the job of measuring snowfall at the airport from the weather service. There are six Top 20 storms since 1998 at BWI that could be affected.

I'm not sure how all this will come out in the wash. It seems likely that, if the FAA's contractors really have used hourly measurements since 1998, that all our snowstorms since then will get smaller. When the problem was discovered last month, Lee rejected the 28.8-inch total the FAA contractor reported for the Feb. 5-6 storm based on its hourly measurements. He replaced it with the more conservative 24.8-inch measurement the contractor reported as the storm's "snow depth" - the total measured when the snow stopped falling (and after the snow's weight had compacted it). 

On the former issue - revisiting the entire storm record at BWI and Washington and ranking snowfalls in separate categories according to the number of days the snow fell - I suppose they have to abide by the rules set by climatologists.

But, on the latter, it seems to me that those of us who are not climatologists experience snowstorms as discreet events based on how much we have to shovel once the flakes stop falling. I would argue that the February 2003 "storm" - while it may have been two storms - felt like one really long siege to those of us left to dig out from 28 inches of snow.

So, in the interests of continuity ... or nostalgia, or something less than scientific ... here is the old NWS Top 20 Snowstorms list for Baltimore, using the old (now officially discredited) criteria, and updated to include the three big storms from December 2009 and February 2010. Clip and save. You may never see it again after the NWS issues its revised lists.

Some observations: February, while it is not the snowiest month on average at BWI, has seen nine of these Top 20 storms, as many as January and March combined. December has seen just two. But what's most astonishing to me, personally, is that, while the record goes back to the 1880s, my family and I have witnessed 10 of these 20 storms since we moved to Baltimore only 30 years ago. How about you? There should be only three or four that no one living today can recall.

1. Feb. 15-18, 2003:  28.2 inchesClearing the roof of snow

2. Jan. 27-29, 1922:  26.5 inches

3. Feb. 5-6, 2010:  24.8 inches*

4. Feb. 11, 1983:  22.8 inches

5. Jan. 7-8, 1996:  22.5 inches

6. Mar. 29-30, 1942:  22.0 inches

7. Feb. 11-14, 1899:  21.4 inches

8. Dec. 18-19, 2009:  21.1 inches

9. Feb. 18-19, 1979:  20.0 inches

10. Feb. 9-10, 2010:  19.5 inches

11. Mar. 15-18, 1892:  16.0 inches

12. Feb. 15, 1958:  15.5 inches

13. Jan. 25, 2000:  14.9 inches

14. Dec. 11-12, 1960:  14.1 inches

15. Feb. 11-12, 2006:  13.1 inches

16. Mar. 5-7, 1962:  13.0 inches

17: Jan. 22, 1987:  12.3 inches

18. Jan. 30-31, 1966:  12.1 inches

19. Feb. 16-18, 1900:  12.0 inches

20. Mar. 13-14, 1993:  11.9 inches  

* Snow depth measurement. The "true" depth, had it been measured every 6 hours, likely would have been more.

(TOP: AP Photo/Rob Carr; BOTTOM: Sun Photo/Gene Sweeney, Jr.)

Posted by Frank Roylance at 10:29 AM | | Comments (9)
Categories: By the numbers

March 1, 2010

Flirting with the 50s ... and a few flakes

We may still have a few flakes in the forecast, but there is a softness in the air now that feels more like spring. That may come from the fact that the thermometer will be pushing toward the 50-degree mark this afternoon - a range we haven't seen since the end of January.

It's March, after all, and the long-term averages for Baltimore are now touching 50 degrees. So when we rise out of the 40s - maybe today, and probably by the weekend - it will just FEEL like an extraordinary gift after all we have been through in the past month.

NOAA GOESThe forecast isn't all tulips and sunshine. Low pressure is developing in Texas and the Gulf of Mexico today. It is expected to make its way over to the Florida coast, turn left and move up the coast by late Tuesday into Wednesday, bringing a bit of wet snow to the southern Appalachians.

In the meantime, another low over the Great Lakes will head our way, bringing light precipitation for a time Tuesday night, probably a mix of rain and snow along the Baltimore-Washington corridor.

National Weather Service forecasters out at Sterling, Va. say points south and east of the cities will see mostly rain from the Great Lakes system, while Western Maryland will likely get more snow. There are no accumulation predictions yet, but amounts are likely to be light.

The coastal low, meanwhile, is forecast to intensify. And while it is expected to stay to our south and move away from our region without contributing much in the way of precipitation, it may well bring us windy conditions Wednesday.

Temperatures will drop, too, as the storms move through, with highs near 40 degrees Wednesday and Thursday before things begin to dry out and warm again toward 50 degrees by the weekend. Sunshine will return, too, by late in the week. Sunday's forecast calls for partly sunny skies and a high near 50.

Here's Eric the Red on the approaching storm systems:

"We have ourselves another close call, but it appears that this coastal low will just miss or merely brush the region Tuesday night and Weds. Coupled with a stronger March sun and increasingly warm 'ambient' conditions, the odds of significant snow now appear slim."

"Things could go wrong: Perhaps the models are not getting the interaction between the Midwestern low and the costal low correct, and the low tracks a bit farther west. If this were to occur, then precipitation amounts would go up. But I'm guessing, if anything, this goes the other way ... This one ... will likely be our last hurrah ... and a small hurrah at that."

Posted by Frank Roylance at 11:00 AM | | Comments (0)
Categories: Forecasts

Meteorological winter ends; one for the records

Although there are still some flakes in the forecast, the three-month meteorological winter ended at midnight last night. So it's a good time to add up the damage and answer some questions I've already been getting from readers.


December: 23.2 inches (Average: 1.7 inches) 

January: 7.5 inches (Average:  7.0 inches)

February: 49.7 inches (Average:  6.4 inches)

Seasonal total*: 80.4 inches (Average: 18.2 inches)

*Through Feb. 28


Snowiest winter: Old record: 62.5 inches in 1995-96

Snowiest December: Old record: 20.4 inches in 1966-67

Wettest December: (8.06 inches melted precip.) Old record:  7.44 inches in 1969

Snowiest February:  Old record: 40.5 inches in 2002-03

Snowiest month:  Old record:  40.5 inches in 2002-03


December:  3

January:  2

February:  6

SNOWIEST DATE OF WINTER (Midnight to midnight): Dec. 19, 2009:  20.5 inches


Dec. 18-19, 2009:  21.1 inches

Feb. 5-6, 2010:  24.8 inches*

Feb. 9-10, 2010:  19.5 inches

* estimated due to measuring error at BWI 

And, just for the record, here's how, back in October, predicted the winter would turn out.

And here's a bit of how the National Weather Service predicted it in an October story in The Sun: Looking back over previous winters in the Baltimore-Washington area during El Nino events, Mike Halpert, deputy director of the National Climate Prediction Center, said, "If you add all the years together there is a tendency for above-average snow ... We've seen with El Nino winters[like this one] a couple of years with absolutely no snow in this area. But we've also seen winters with some record-breaking snows. It's a feast-or-famine type of situation."

I guess we got the feast, Mike.

(SUN PHOTOS/Frank Roylance)

Posted by Frank Roylance at 10:08 AM | | Comments (5)
Categories: By the numbers
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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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