Friday, March 25, 2011

Rare late season snow becoming more likely--

March 30 2003-- a heavy rain switches to a driving heavy wet snow. Roanoke to Blacksburg had 4-8 inches. Lynchburg had 5+ inches fall, but only a 2 inch max depth. At my Forest home-- we had an inch, a lull which allowed it to melt and another 2 inches that accumulated.

This is the last latest snow in our region. In April 2007 we barely missed a late season snow that coating the ground from NE NC-- Mebane NC had a coating.

Same set up as before-- The cold has been trending a smidge colder, but the models do want to punch a warm later through between 7 and 10k feet. This is a tremendously cold air mass so even when this happens, the snow would partially melt and fall as snow grains rather than pure sleet. When I examine the layers of the atmosphere and see that in theory Roanoke and Lynchburg are supposed to change to sleet before Richmond-- usually this indicates this warm air push is not only very likely, but often will occur sooner than modeled.

Brutally cold day Sunday for LATE March-  temps may struggle to reach freezing once the snow starts, even with a strong late day March sun.

My best guess now is start time between 10 PM far west to 2 AM far east overnight Saturday into Sunday.

Martinsville to Danville-- rain, mixing with sleet. Sleet could coat the ground.

Blacksburg, Roanoke, Lynchburg-- could have a little rain to start, but snow-- changing to snow grains and sleet ending as flurries.  (Snow grains look like rice) 1-3 inches.

Jackpot-- Lexington to Hot Springs to Harrisonburg to Waynesboro into Charlottesville-- 2-5 inches, best accumulations at the highest elevations. Would not be shocked to hear a 6-7 inch total from Afton Mt or some other elevated location.

We are about 48 hours out from this event-- so it has some wiggle room to change. I'm always leery of the "north trend" the models often display. In terns of wiggle room-- we don't have much because Danville starts as rain and changes to sleet as modeled now well into the event. 60 miles isn't much of a jog in 48 hours. Having said that-- there has been remarkable consistency in the models for days now. Still, I've seen the north trend OVER and OVER in years past-- sometimes the models never even show it, but it takes place anyways.

As a result, I'm in full storm mode-- blog updated 2x a day until this event passes by.

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