Severe thunderstorms will be possible Wednesday afternoon and evening across much of Virginia. Surface dew points in the upper 60s and low 70s will combine with surface heating resulting in a moderate to very unstable atmosphere by afternoon. An approaching upper-level impulse and associated weak surface boundary will act as triggering mechanisms for storms, some of which will likely be severe. The environmental wind shear should be unidirectional, resulting in damaging straight-line winds as the primary severe mode. The axis of greatest shear and moisture should lie across north-central and northeastern Virginia. I would expect a severe thunderstorm watch to be issued for much of the area Wednesday afternoon. Farther north into Maryland and Pennsylvania, better dynamics and shear structure could result in a few tornadoes. The greatest limiting factor for storm development will be the extent of cloud cover associated with tonight's convection across the Southern Great Lakes and Ohio Valley. We'll have the latest on Wednesday's severe weather potential on CBS 6.
