SPC AC 040536

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1236 AM CDT Sat May 04 2024

   Valid 041200Z - 051200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHERN HIGH PLAINS INTO THE EDWARDS PLATEAU...

   ...SUMMARY...
   Scattered severe thunderstorms are expected across parts of the
   southern High Plains into the Hill Country of central Texas this
   afternoon and evening. Several storms may produce very large hail,
   and a couple strong tornadoes are possible.

   ...Southern High Plains to the Hill Country of TX...

   Water-vapor imagery depicts a low-amplitude short-wave trough off
   the Baja Peninsula. This feature will advance across northern Mexico
   by early evening as a 500mb speed max translates toward the Big Bend
   of west TX, subsequently moving into central TX by 05/12z. A
   reservoir of very moist/unstable air will reside across south
   TX/Edwards Plateau into portions of west TX. Robust convection will
   easily develop ahead of the short wave and quickly become severe
   during the afternoon. Very large hail and the threat for tornadoes
   can reasonably be expected.

   Early this morning, surface pressures are building across the
   central Plains in the wake of ejecting northern-stream short-wave
   trough. Surface front will surge across the TX South Plains early in
   the period, and will likely arc along/near I-20 into southeast NM by
   18z. Latest model guidance suggests strong boundary-layer heating
   will occur ahead of the wind shift across far west TX into the Trans
   Pecos. Forecast soundings, south of the front, suggest surface
   parcels will reach their convective temperatures by 20z, just east
   of the dryline. This feature will be forced deep into west TX and
   will be one of the foci for convective development, along with the
   cold front. Latest NAM PFC for INK at 20z exhibits MLCAPE on the
   order of 3500 J/kg with surface-6km bulk shear around 45kt.
   Scattered supercells will likely develop by mid afternoon and
   quickly attain severe levels. This activity will grow upscale and
   shift downstream, aided by the progressive short wave. In response
   to the short wave, LLJ is forecast to focus across west TX through
   early evening then strengthen and shift east toward the I-35
   corridor by sunrise Sunday. Initial convective mode will be
   supercellular and very large hail can be expected. Additionally,
   moistening boundary layer will support tornadoes, possibly strong,
   as shear will be strong. With time, MCS is expected to mature and
   propagate toward central TX during the overnight hours.

   ..Darrow/Wendt.. 05/04/2024

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