SPC AC 071951

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0251 PM CDT Wed Jun 07 2023

   Valid 072000Z - 081200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SEVERAL
   AREAS OF THE CONUS...

   ...SUMMARY...
   Isolated severe thunderstorms with wind and hail remain possible in
   several areas of the country this afternoon and evening: the
   southern High Plains, the South Carolina vicinity, south to east
   Florida, the interior Northwest, and the eastern Dakotas.

   ...20Z Update...
   Some minor changes have been made to the general thunderstorm lines
   across NC/VA, but severe probabilities remain unchanged. The
   potential for a supercell or two late this afternoon into this
   evening remains evident across the TX Trans Pecos, with generally
   more disorganized threats scattered elsewhere across the CONUS. 

   For more information regarding the short-term threats, see MCD 945
   across Florida, MCD 946 across South Carolina, and MCD 947 across
   eastern NM into the TX Panhandle/South Plains. Also see the previous
   discussion below for more information.

   ..Dean.. 06/07/2023

   .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Jun 07 2023/

   ...Southern High Plains...
   A southern-stream upper jet will gradually expand east across much
   of northern Mexico. Within the left-exit region of this jet,
   isolated to scattered thunderstorms will develop over the higher
   terrain of the TX Trans-Pecos and eastern NM. Proximity of a
   low-amplitude mid-level ridge will yield weak deep-layer shear north
   of the Trans-Pecos, with the latter seeing strengthening flow during
   the late afternoon into the evening. Here, a couple supercells
   should form with a primary threat of isolated large hail before
   clustering towards the Rio Grande. Farther north, loosely organized
   multicell clusters should dominate with sporadic occurrences of
   severe hail and wind possible through early tonight.

   ...Southeast...
   Scattered thunderstorm development appears to be commencing across
   the south to eastern FL peninsula, with additional storms likely to
   form later this afternoon near a southward-sagging cold front in the
   SC vicinity. Belts of 30-40 kt west-southwesterlies will persist
   across central to south FL ahead of a low-amplitude trough over the
   east-central Gulf and along the frontal zone to the south of the
   amplified trough across the Northeast. While low-level flow will be
   weak over FL and predominately westerly over the SC vicinity,
   adequate effective bulk shear will exist for transient supercell and
   multicell structures capable of isolated damaging winds and
   lower-end severe hail.

   ...Northeast CA to southwest MT...
   A weakening upper low will drift northeast from southeast CA into
   southern NV. This will result in gradual decay of the mid-level wind
   field. However, adequate speed shear from the mid to upper levels
   should still support semi-organized multicell clustering later this
   afternoon, mainly across southern to eastern OR and the southern
   half of ID. Similar to yesterday, isolated severe wind gusts will be
   the primary threat, with small to marginally severe hail also
   possible.

   ...Eastern Dakotas...
   A mid to upper-level anticyclone will remain anchored over the
   central Dakotas. A pocket of moderate buoyancy should develop across
   a portion of the eastern Dakotas where boundary-layer dewpoints can
   hold from 60-64 F. While deep-layer flow will remain weak,
   directional change with height from light low-level
   south-southeasterlies to weak mid-level northerlies may yield a
   strip of 15-20 kt effective bulk shear. A few marginally severe wind
   and hail events from pulse to weakly organized multicells remain
   possible during the late afternoon to early evening.

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