Today’s frontal passage – accompanied by a developing surface low pressure – may provide a brief period of chasing excitement in western VA late this afternoon.  The limiting factor as usual in the fall is very little instability, with CAPE values <500 across the region.  However, the shear values could be off the charts according to the 11Z HRRR run.  This is the deep layer shear (0-6 km) forecast graphic for 6 pm today:

With deep layer shear numbers well over 50 knots (and 0-1 km shear near 25 knots) the classic high shear low CAPE setup will be in place.

The big question is whether or not there will be enough forcing to create robust enough updrafts to tap into this shear.  A quick peek at a simulated radar view shows a line of enhanced reflectivity along the frontal boundary that could tap into that shear west of the Blue Ridge mountains before dark.  I may just have to sidle out to a local vantage point around dinner time…

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