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Yes, Virginia, there will be snow Tuesday

UPDATE: The National Weather Service has changed the Winter Storm Watch to a Winter Storm Warning for Tuesday from 7 a.m. to 11 p.m.


The question is, “how much?” Last night I had my doubts about the increasing buzz regarding accumulating snow Tuesday but now I’m sold on the idea, especially with Winter Storm Watches posted for most of the region! As late as yesterday morning the forecast models were being very stingy with moisture. This restricted the precipitation amounts but the last several model runs have turned that trend around. As I write this I have just reviewed this morning’s 7 a.m. run of the North American Model and it continues to support the idea of more vs. less snow for Fredericksburg.


FORECAST: Check here for the latest forecast

CLOSINGS / LATE OPENINGS: Check here for the latest schedule changes.


[A note to weather nerds (the rest of you can skip this paragraph): Most forecast models spit out results four times daily at 06Z (1 a.m. EST), 12Z (7 a.m.), 18Z (1 p.m.), and 0Z (7 p.m.). Of those four runs only the 12Z and 0Z runs incorporate new upper air data from balloon launches by the National Weather Service. The 06Z and 18Z runs are just a rehash of the previous upper air data plus updated surface conditions. Thus I pay much more attention to the 12Z and 0Z model runs because of the additional data.]

Now for some details. Today – Monday – will make the thoughts of snow seem very far away. A low temperature of 36 degrees this morning at the UMW weather station will be followed by a high rising into the low 50s under mostly sunny skies. That will all change behind a cold front that will push across the I-95 corridor this evening to begin the next Arctic air invasion. The passage of this boundary will be dry but then a strong upper level shortwave trough – another Alberta Clipper – quickly dives into our area behind it.

This Clipper will cause a “buckle” in the cold front to our south, creating a surface low pressure system that will be much more vigorous than originally thought. This stronger low will wrap in significant moisture off the Atlantic Ocean late tonight. The combination of this moisture and the much colder air in place Tuesday (highs only in the 20s tomorrow!) will result in significant snow. Here’s a section of the Weather Prediction Center probability map:Day2 snow probsThe green contour surrounding Fredericksburg and vicinity indicates a 40-70% chance of 4 inches or more of snow (areas inside the red contour have more than a 70% chance).

Light snow will likely begin around the ‘Burg by 9 a.m. Tuesday and pick up in intensity during the remainder of the daylight hours before tapering off during the early evening. Given the amount of moisture now thought to be available and with air temperatures well below freezing the NWS Sterling forecast of 3-5 inches seems to be spot on. The rest of this week’s weather story centers on the very frigid air that will settle over us.

To sum up: Tomorrow will be tough going on the roads around the area and frigid conditions will take over. In fact, Wednesday morning’s low temperature will be in the single digits and may even approach zero. Winter is making an appearance!!

Permalink: http://news.fredericksburg.com/weather/2014/01/20/yes-virginia-there-will-be-snow-tuesday/

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