SPC AC 141626

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1126 AM CDT Wed Jun 14 2023

   Valid 141630Z - 151200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   INTO TONIGHT FROM THE ARKLAMISS ACROSS AL INTO SOUTHWEST GA...

   ...SUMMARY...
   Significant severe thunderstorms capable of producing all severe
   hazards, including very large hail, swaths of intense wind
   gusts/damage, and tornadoes, are expected from the ArkLaTex into the
   Southeast this afternoon into tonight.

   ...ArkLaTex to GA through tonight...
   The unusually strong flow pattern continues from the southern Plains
   eastward to the Southeast, with 50+ kt midlevel flow across the
   corridor, coincident with steep midlevel lapse rates and strong
   buoyancy.  Embedded speed maxima will move generally eastward
   through this corridor, around the southern periphery of the midlevel
   closed low over the lower Great Lakes.  The primary severe threat
   will continue through the afternoon and into tonight from the
   ArkLaTex across MS/AL into southern GA.

   Multiple clusters of severe storms are ongoing, including both
   supercells and line segments.  The cluster in northern MS will
   likely persist through the afternoon while moving east-southeastward
   across central AL, where additional supercell development is
   expected within the warm sector ahead of the cluster.  The
   environment of large buoyancy (MLCAPE 3000-4000 K/kg) and effective
   bulk shear in excess of 60 kt is quite unusual for mid June into the
   I-20 corridor, and this will support an unusually high threat for
   severe storms (including significant severe events).  Supercells
   will be capable of producing isolated very large hail to near 3
   inches in diameter with the supercells forming in northeast TX, and
   with supercells farther east into AL.  A complex storm evolution is
   expected from MS across AL into GA along the buoyancy gradient, as
   the ongoing clusters and new storms interact and potentially support
   upscale growth into larger clusters.  

   Swaths of wind damage, some up to 80 mph, can be expected with the
   MS/AL clusters this afternoon and into GA along the residual outflow
   boundary.  This boundary will locally enhance low-level shear, with
   the potential for a few tornadoes (a couple of which could be
   strong), from southwest GA into southeast/central AL with both the
   isolated supercells and with embedded circulations in any larger
   clusters.  Another cluster could evolve from the northeast TX
   supercells, and this convection will have a corridor of strong
   instability to support its maintenance across northern LA into
   central MS and eventually AL later this afternoon into early
   tonight.  The initial supercells could produce very large hail,
   while upscale growth will favor swaths of damaging winds (some
   significant), as well as a few tornadoes.

   ...Central TX this afternoon/evening...
   Strong-extreme buoyancy is expected again across central TX, but
   forcing for ascent will be weak.  If sufficient heating/mixing can
   occur, an isolated storm may form this afternoon along the surface
   front into central TX.  The environment conditionally favors
   splitting supercells with very large hail, though storm
   formation/coverage is uncertain.  

   ...Northern Mid-Atlantic/southern New England this afternoon...
   Pockets of surface heating will drive weak buoyancy to the east of
   the low across southern New England, where isolated strong-severe
   storms may occur (see MD #1037 for additional information).

   ..Thompson/Squitieri.. 06/14/2023

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