U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 250730 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0230 am CDT Tue Apr 25 2017 

Valid 271200z - 281200z 

..there is a marginal risk of severe thunderstorms from the 
southeast states through the Ohio Valley and Great Lakes... 

At least a marginal risk for a few severe storms will exist from a 
portion of the southeast states into the Ohio Valley and Great Lakes 
on Thursday. 


Lead shortwave trough embedded within a broad synoptic trough will 
continue northeast through the Ohio Valley and Great Lakes early 
Thursday. Farther upstream, a series of vorticity maxima north of an 
evolving upper jet core will advance southeast through the Great 
Basin, southern rockies and Southern Plains. At the surface the 
cyclone attending the lead shortwave trough will occlude over the 
Great Lakes, while trailing cold front continues through the Ohio and 
Tennessee valleys. Trailing portion of this front will stall and return 
north as a warm front across Texas in response to Lee cyclogenesis over 
the southern High Plains. 

..southeast states... 

Reservoir of Richer low-level moisture with dewpoints in the 60s f 
will reside over a portion of the southeast states warm sector 
contributing to marginal to moderate instability. It is likely that 
a linear mesoscale convective system will be ongoing over a portion of Tennessee into Alabama and the Florida 
Panhandle, and these storms may pose an ongoing risk for mainly 
damaging wind as they continue east during the morning into the 
early afternoon. Tendency will be for the deeper forcing and 
stronger low-mid level winds to develop well north of this region in 
association with the shortwave trough moving northeast through the 
Ohio Valley and Great Lakes. This may serve as a limiting factor for 
a longer duration, organized severe threat. Nevertheless, a slight 
risk might be needed for a portion of this region in future updates. 

..Ohio Valley and Great Lakes... 

The feed of Richer low-level moisture will become limited as the 
cyclone occludes over the Great Lakes region. However, at least 
marginal instability within a strong shear environment will exist in 
pre-frontal warm sector, and ongoing storms may pose a risk for a 
few instances of mainly isolated damaging wind during the morning 

.Dial.. 04/25/2017