SPC AC 251634

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1134 AM CDT Sat May 25 2024

   Valid 251630Z - 261200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
   OKLAHOMA...CENTRAL AND EASTERN KANSAS...AND SOUTHWEST MISSOURI...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
   ALABAMA AND SOUTHWEST GEORGIA...

   ...SUMMARY...
   An outbreak of severe thunderstorms is possible from late afternoon
   into tonight over parts of the central and southern Plains.  A few
   long-lived supercells capable of intense tornadoes may occur.  Giant
   hail and destructive wind gusts are also expected.

   ...Central/Southern Plains...
   Overall, little change was made to the ongoing outlook with this
   update, with the primary change being an eastward expansion of the
   Enhanced/Level 3 Risk over portions of North Texas based on the 12z
   HREF guidance. 

   Strong low-level moisture advection continues across northwest
   TX/southern OK at 16z, and this trend is expected to continue and
   expand north into southern KS with time. Strong diurnal heating amid
   a rapidly moistening boundary layer and steep mid-level lapse rates
   will yield strong/extreme MLCAPE this afternoon along and east of
   the dryline. 

   Initial supercell development is anticipated late this afternoon
   across northwest TX, where strong diurnal heating should continue to
   erode CINH. Isolated intense supercell development is also expected
   farther north along the dryline towards 00z across OK/southern KS,
   where rapidly returning moisture into a well-heated boundary layer
   coincident with a strengthening low-level jet should contribute to a
   high-end/all hazards severe risk.  Additional isolated supercell
   development is also anticipated near the warm front across northern
   KS. The primary uncertainty remains storm coverage, with 12z
   high-res guidance continuing to exhibit a range of solutions.  As
   mid-level flow increases and a shortwave trough approaches, an
   extremely favorable thermodynamic and kinematic environment is
   expected to be in place across the Enhanced/Moderate Risk areas from
   late afternoon into tonight. The risk for strong/intense tornadoes,
   very large to giant hail, and significant severe winds remains
   evident.  

   ...Southeast...
   Rapid diurnal heating of a moist low-level air mass is occurring
   downstream of ongoing convection, and temperatures have warmed well
   into the 80s as of 16z. Strong thunderstorms over southeast AL are
   expected to continue moving southeast within a
   moderately-sheared/northwest flow environment and be capable of
   strong/possibly damaging gusts and severe hail.  A small
   Slight/Level 2 Risk has been introduced with this outlook, where the
   more favorable overlap of 35 kts of northwesterly effective shear
   and moderate/strong instability will exist.  

   ...Lower Great Lakes/upper Ohio Valley...
   Widely scattered to scattered thunderstorms are expected near the
   cold front this afternoon, and along a nearly parallel, prefrontal
   trough/convergence zone. Storms should move eastward/southeast and
   persist into early evening.  

   Aside from lift along those boundaries, activity will be supported
   by diurnally weakened MLCINH, with surface dewpoints in the upper
   50s to mid 60s F contributing to around 1500 J/kg MLCAPE.  Weak
   low-level flow and nearly unidirectional low/middle-level wind
   profiles will tend to limit shear, however sufficient cloud-bearing
   layer shear should exist to support multicell storm structures. 
   Damaging gusts and isolated hail will be possible from the
   best-organized convection.

   ..Bunting/Squitieri.. 05/25/2024

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