SPC AC 041642

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1142 AM CDT Sat May 04 2024

   Valid 041630Z - 051200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR WEST
   TEXAS...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL AND
   NORTHWEST ILLINOIS...

   ...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.

   ...TX/southern OK/extreme southeastern NM...
   Not much change for this outlook update other than a minor southward
   shift of severe probabilities across far southeast NM and West TX to
   account for the projected cold front position by mid afternoon. 
   Still expecting widely scattered to scattered thunderstorms to form
   this afternoon along and behind the cold front over west TX and
   southeastern NM, as well as ahead of the cold front, near the
   dryline and over strongly heated, relatively high elevations west of
   the Pecos Valley.  The stronger updrafts will attain supercell
   characteristics and pose a large-hail threat on both sides of the
   front, with severe-wind and tornado potential more prevalent to its
   south.  Forecast soundings south of the front indicate veering and
   increasing flow with height which will become very favorable for
   supercells.  It still appears one or two dominant, prefrontal,
   mid/late-afternoon supercells may evolve and remain south of the
   front.  The potential for a strong tornado in addition to giant hail
   will be the primary hazards with these warm sector supercells. 
   Additional storm development is expected by early evening with an
   amassing of cold pools eventually expected, as southeasterly 850mb
   flow strengthens.  A severe MCS will likely evolve during the
   evening and probably persist into the overnight as it moves east
   across portions of the Edwards Plateau and central TX.  Have
   expanded wind probabilities farther east to account for a lingering
   threat for severe gusts and perhaps a localized risk for a tornado
   late as this activity moves east of I-35.

   ...North/northeast TX to mid Mississippi Valley/western Great Lakes
   vicinity...
   A diurnal intensification of isolated to scattered thunderstorms is
   expected this afternoon within this general corridor from the Red
   River Valley northeastward into the IL/WI vicinity.  With much of
   this region located in between larger-scale mid-level waves, modest
   kinematic fields will tend to limit overall storm organization and
   severe potential.  Nonetheless, heating of a moist boundary layer
   will facilitate the development of moderate instability by early to
   mid afternoon.  Mainly semi-organized bands of multicells and
   clusters thereof will occasionally result in sporadic potential for
   wind damage and large hail.  It appears perhaps a corridor for
   greater wind damage potential may occur immediately ahead/downstream
   of an MCV moving east across the mid MS Valley.  Model guidance
   indicates slightly greater organized line segments and wind
   potential later this afternoon from central into northern portions
   of IL.  Have also expanded the MRGL northward into portions of WI
   where sufficient destabilization will occur ahead of a front and
   associated mid-level disturbance over the Upper Midwest.

   ..Smith/Bentley.. 05/04/2024

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