Wednesday, March 3, 2010

"Late last night..."
Lyrics from Mrs. O'Leary's Cow about the 1871 Great Chicago Fire

5:30 PM WED 3.3.2010
Rain showers continue across the area as the rotating bands of a deepening oceanic low pressure exit the Mid-Atlantic region this evening. All shower activity should end around 9 pm tonight. However, grey skies will persist overnight, which will offset cooler temperatures brought on by the northwesterly flow which often follows an exiting low pressure system. All of this may sound dreary, but no worries. Sunny skies and much milder temperatures are lining across the eastern U.S. this weekend - the first nice one of it's kind in quite some time!
- update by Forecaster Dakota   

8:00 AM 3.3.2010
TODAY: Brief periods of wet snow mixed with rain are possible this morning along the I-95 corridor, DelMarVa, central/eastern Pennsylvania, New Jersey and into southern New England. This due to potential "wrap-around" snow as the coastal system, a surprisingly low 984 mb at 4:00 AM, deepens while racing offshore. "Upslope" snow showers are likely across the Blue Ridge as colder air replacing the departing low is dragged up the mountains, encountering residual moisture skimmed from the Great Lakes.

HMM.. SNOW IN NY STATE So why did snow move into New York State, when that was not part of the plan?  A little canary in the coal mine overlooked until too late. Know the old song about the Great Chicago Fire? "Late last night, while we were all in bed, Old Mother Leary left a lantern in the shed, and when the cow kicked it over, she winked her eye and said, 'there'll be a HOT time in old town tonight...' "

THE ANALOGY: We saw the North Atlantic Oscillation (NAO) might display a shift toward neutral in the March 1-3 period as shown on the 7-day projection. That roughly translates into a 50-100 mile drift in an eventual storm track, a factor not accounted for in the forecast. Granted our meteorology colleagues would remind that a plethora of other factors contributed, including lack of a surface high, recent snowcover and the dynamics of a deepening coastal system. Warm air surged ahead of the storm as it filled the gap created by a lessening NAO-- hence "hot time in the old town tonight."

NEW UPDATING PLAN The team understands many readers check here several times a day, even though future chances of snow are decreasing. For those needing updates on rain and severe weather threats, our proposed post times* may help:
(1) 6:00 - 7:00 AM; (2) 11:00 AM - 12:00 PM;
(3) 4:00 - 5:00 PM; (4) by 9:00 PM and overnight as needed.
*Note: For the "main site," check individual zones for update times.

SEVERE WEATHER When thunderstorms or tornadoes threaten in the eastern U.S., details will be handled in the Severe Weather & Safety Zone to be launched this weekend. Forecaster Daniel Ross,* a meteorology student at Georgia Tech, will lead the collaboration include "meteo" students from the Penn State Team* and the Maryland high school team,* as well as our advisors in Virginia and elsewhere. The weather is not taking a break, so neither will we!  *Many thanks to all for the day and night multi-collaborative efforts on tackling the evolving system.

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