SPC AC 121715

   Day 1 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   1215 PM CDT Sun Jun 12 2022

   Valid 121630Z - 131200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
   NORTH-CENTRAL HIGH PLAINS...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
   MIDWEST/LOWER OHIO VALLEY AND VIRGINIA/NORTH CAROLINA...

   CORRECTED FOR TYPOS

   ...SUMMARY...
   Scattered severe thunderstorms are expected across the northern and
   central High Plains late this afternoon into tonight, with large
   hail and damaging winds the main threats. Isolated severe storms may
   also be noted across the lower Ohio Valley and parts of the southern
   middle Atlantic.

   ...Northern/central Plains to Upper Midwest...
   Regional upper-air analysis reflects an axis of moderate low-level
   moisture extending west/northwestward across the north-central High
   Plains this morning. This coincides with a belt of strong mid/high
   winds that precede an amplifying trough over the Pacific Northwest,
   with the aforementioned stronger winds extending over the northern
   Rockies east-northeastward into the Dakotas/Minnesota. 

   Influenced by increasing larger-scale forcing for ascent and
   orographic lift in vicinity of mountains/higher terrain, increasing
   thunderstorm development is likely by mid-afternoon across northern
   Wyoming/southern Montana, and a bit later toward the Black Hills
   vicinity and southward along the lee trough/boundary into western
   Nebraska/northeast Colorado. Initial supercells capable of large
   hail can be expected, along with some tornado risk and a higher
   probability of very large hail particularly across northeast
   Wyoming/far southeast Montana into western South Dakota. 

   Confidence has increased that a higher probability corridor of
   severe storms including upscale growth into one or more MCSs should
   evolve this evening across western/central South Dakota as well as
   western Nebraska. An Enhanced Risk has been added to these areas.

   ...Missouri/Kentucky and southern Illinois/Indiana...
   Complex short-term scenario across the region with multiple residual
   influences (MCV etc.) from last night's middle Missouri Valley MCS.
   A consequential reservoir of moisture exists across the region per
   12z upper-air 850 mb analysis, extending from northern/eastern
   Kansas into Missouri and southern portions of Illinois/Indiana into
   northern Kentucky. This will contribute to a very unstable air mass
   with upwards of 4000-6000 J/kg MLCAPE. However, a major complicating
   factor, in terms of uncertainty, is expectations for steady
   mid-level warming via the eastward-advecting elevated mixed layer.
   12z Topeka, KS observed sounding featured a 15.2 C 700 mb
   temperature, while Springfield, MO was 13.6 C. Short-term model
   guidance varies considerable in this modest forcing/prevalent
   mid-level warmth scenario. 

   However, storm persistence/development through this afternoon will
   likely regionally favor the cooler side of this notable mid-level
   thermal gradient, with more probable storms across downstate
   portions of Illinois/Indiana into Kentucky. It is plausible that a
   severe risk, at least on an isolated basis, impacts at least parts
   of the region through the afternoon into evening, with potential
   late-night redevelopment on the eastern edge of the cap. Damaging
   winds and large hail will be possible in what could be a
   multi-round-related storm risk for parts of the region.

   ...Virginia/North Carolina...
   A cluster of strong/severe storms will continue to impact far
   southeast Virginia vicinity through early afternoon. Otherwise, a
   relatively moist and potentially unstable air mass is present to the
   west of these early day storms. Forecast soundings suggest
   sufficient deep-layer shear for convective organization and perhaps
   a supercell or two. Overall, locally damaging winds are the main
   threat through the early evening.

   ..Guyer.. 06/12/2022

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