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Neither the Storm Prediction Center Day 3 convective outlook nor the NWS Blacksburg forecast discussion are bullish on severe weather Thursday. Of course that has never stopped me from being optimistic about such things!!

The NAM has consistently shown more instability than the GFS (surprise, surprise) but both of them show >500 j/kg CAPE Thursday afternoon over the Piedmont. The SREF seems to agree as shown in this graphic:

srefSE_con_cape500_066

The bulk shear values are all >>40 knots and dewpoints are >55 with LCLs consistently less than 900 meters. All of that leads to high shear / low CAPE chasing hopes illustrated by this GFS supercell composite parameter graphic for 21Z:

gfsSE_con_scp_063

The main concern is that successive model runs have slowed the forward progress of the cold front, with low pressure over the Ohio valley stalling the frontal passage until after dark. Thus the front as the lifting mechanism seems to be a non-starter.

However I’m thinking the lee trough could provide the lift necessary to get updrafts going Thursday afternoon. I’ll have to wait until short range models come within range to check out that hypothesis, but that would likely mean an initial staging point along U.S. Route 29 to watch the lee trough. Timing is the key here as I don’t intend to twiddle my thumbs for several hours awaiting convection.

Wednesday will thus entail model-watching and final chase gear preps.

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