SPC AC 040539

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1239 AM CDT Tue Aug 04 2020

   Valid 051200Z - 061200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   NORTHEAST CO...WESTERN NE AND SOUTHEAST WY...

   ...SUMMARY...
   Strong to severe storms capable of strong wind gusts and large hail
   are possible Wednesday afternoon and evening over portions of the
   central High Plains.

   ...Central/Southern High Plains Vicinity...

   Northwesterly flow aloft will continue over the Plains on Wednesday.
   An upper ridge will remain oriented over the southern Rockies
   north/northwest to the MT/ID border vicinity while an upper trough
   along the Pacific Coast begins to dig southward as it moves inland
   late in the period. A weak shortwave impulse is forecast to eject
   across the central Rockies ahead of the upper trough during the
   afternoon/evening, resulting in weak height falls and increasing
   upper forcing. In lower levels, southeasterly upslope flow will
   transport modest boundary layer moisture north and west along a
   surface trough extending north-south along the central High Plains.
   This should allow weak to moderate destabilization during peak
   heating, and thunderstorms are first expected to develop over higher
   terrain by mid-to-late afternoon. Effective shear greater than 30 kt
   amid steep midlevel lapse rates and somewhat long/straight
   hodographs will allow for organized convection to be maintained as
   it moves eastward off the higher terrain and over the adjacent
   Plains. High-based supercells and storm clusters will pose a threat
   for locally damaging gusts and large hail through the evening hours.
   Inhibition will increase with eastward extent and convection should
   weaken during the early overnight hours.

   ...Portions of eastern ND/SD into southwest MN...

   A weak surface boundary will extend from western NE into the eastern
   Dakotas Wednesday afternoon/evening. Weak southerly low level flow
   will result in some increase in boundary layer moisture, but
   guidance varies on the degree of moisture return. Some guidance
   suggests isolated storms could develop diurnally near the surface
   boundary, but weak shear and modest forcing should limit overall
   organization. While a strong storm is possible, the overall threat
   appears too conditional/uncertain to include severe probabilities at
   this time.

   ..Leitman.. 08/04/2020

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z