SPC AC 190049

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0749 PM CDT Thu Apr 18 2024

   Valid 190100Z - 191200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE MIDDLE MISSISSIPPI AND LOWER OHIO VALLEYS...

   ...SUMMARY...
   Severe thunderstorms should be most concentrated over portions of
   the middle Mississippi and lower Ohio Valleys early tonight. More
   isolated activity is expected farther south across Arkansas into
   south-central Texas.

   ...01z Update...

   Low-amplitude short-wave trough is currently ejecting east across
   IL. This feature is forecast to advance into eastern OH by sunrise.
   Large-scale support ahead of this feature is expected to encourage
   ongoing MCS over the middle MS Valley to propagate downstream across
   the remainder of southeast IL into southern IN later this evening.
   This MCS is currently severe and has produced a variety of wind/hail
   reports across MO/western IL. Current thinking is wind/hail will
   continue to accompany this squall line, at least into the lower OH
   Valley where it will encounter weaker buoyancy.

   Surging cold front has advanced into northwest AR, arcing southwest
   across southeast OK into the Edwards Plateau of southwest TX.
   Thunderstorms have struggled to develop along portions of this wind
   shift, but isolated robust convection is currently sagging south
   through the Hill Country, just north of Llano. Very large hail may
   yet accompany this activity before low-level lapse rates weaken.
   Convection should remain isolated along the trailing cold front due
   in large part to negligible large-scale forcing. Nocturnal cooling
   should limit coverage across this region.

   ..Darrow.. 04/19/2024

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