SPC AC 100119

   Day 1 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0819 PM CDT Fri Apr 09 2021

   Valid 100100Z - 101200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
   MISSISSIPPI VALLEY...

   CORRECTED TO REMOVE SLIGHT RISK IN THE MIDDLE ATLANTIC

   ...SUMMARY...
   Severe thunderstorms with potential for all hazards are expected
   tonight from eastern Oklahoma and east Texas across the Mid-South
   and Mississippi Delta regions, to Alabama. This includes a threat
   for a swath of severe wind across the lower Mississippi Valley.
   Tornadoes are also possible, especially across the lower Mississippi
   Valley. A few severe storms will linger for the next few hours
   across northern North Carolina and southeast Virginia.

   ...01z Update...

   Earlier thoughts regarding the general evolution of severe remain;
   although, a few modifications will be applied to regions that have
   stabilized due to earlier thunderstorm clusters, especially across
   portions of southeast AR.

   An expansive corridor of thunderstorms has evolved over the lower MS
   Valley and currently extends from northern MS-northern LA-eastern
   TX. This complex of storms has overturned the air mass across
   southeast AR and buoyancy may struggle to appreciate much before the
   next cluster digs into this region from OK. For this reason severe
   probabilities have been lowered to reflect the rain-cooled boundary
   layer.

   00z sounding from FWD is impressively unstable with MLCAPE values on
   the order of 3500 J/kg. OUN, though not as unstable, exhibits steep
   lapse rates in proximity to convection that is evolving along/ahead
   of the cold front over eastern OK. Latest radar data suggests this
   convection is gradually maturing into a squall line that should
   propagate southeast toward the Arklatex, along the southwestern
   perimeter of the aforementioned rain-cooled AR bubble. Maturing
   linear MCS should eventually catch up to the western flank of the
   lower MS Valley complex later tonight, then propagate east toward MS
   after midnight.

   The potential for all severe hazards remain with this multi-faceted
   severe threat tonight.

   ..Darrow.. 04/10/2021

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z