U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 250732 
Storm Prediction Center ac 250731 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0231 am CDT Mon Jun 25 2018 

Valid 271200z - 281200z 

..there is a marginal risk of severe thunderstorms from the Ohio 
Valley eastward into western Virginia and Pennsylvania... 

Scattered strong to severe storms are possible from the Ohio Valley 
eastward into western Pennsylvania and Virginia on Wednesday. 

A shortwave trough will move eastward across the Ohio Valley during 
they day, and will lose amplitude as it continues across the 
northeast. At the surface, low pressure will move from lower Michigan 
across the lower Great Lakes, with a cold front trailing 
southwestward across Ohio and into the middle MS valley. Ahead of 
the low, substantial southwesterly flow will spread warm and moist 
air northward, with widespread upper 60s f dewpoints supporting 
areas of moderate instability. 

To the west, fast zonal flow aloft will exist across the northern 
rockies into the northern plains, with rising heights overnight as 
an upper trough develops over the northwestern states. A nocturnal 
southerly low-level jet will transport a moist and unstable air mass 
northwest across the northern plains, possibly supporting isolated 
marginal storms. 

..OH/WV/PA and surrounding states... 
A large area of strong instability will exist across much of the Ohio 
and Tennessee valleys, with MLCAPE in excess of 2000 j/kg common. Flow 
aloft with the upper wave will result in marginally favorable wind 
profiles supportive of clusters of severe storms, and a zone of 
veering winds with height across PA into WV may enhance srh and 
support an isolated supercell. However, scattered storms are 
possible throughout the day producing rain and outflow, which lends 
uncertainty to placing a slight risk due to air mass contamination. 

.Jewell.. 06/25/2018