SPC AC 240729

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Sun Sep 24 2023

   Valid 261200Z - 271200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID MISSISSIPPI VALLEY AND PECOS VALLEY TO BIG BEND...

   ...SUMMARY...
   Thunderstorms, associated with strong winds and hail, will be
   possible on Tuesday across parts of the mid Mississippi Valley and
   Pecos Valley to Big Bend.

   ...Mid Mississippi Valley...
   An upper-level low is forecast to move southeastward across Iowa on
   Tuesday, as a cold front advances southward into northern Missouri
   and western Illinois. Ahead of the front, surface dewpoints around
   60 F along with surface heating will result in weak destabilization
   across much of the mid Mississippi Valley by afternoon. A small
   pocket of moderate instability could develop by late afternoon, most
   likely in Missouri. Scattered convection is expected to initiate
   ahead of the upper-level low and near the front, with storms moving
   southeastward across the mid Mississippi Valley. Forecast soundings
   near St. Louis at 00Z/Thursday have MLCAPE near 1500 J/kg, with 0-6
   km shear around 30 knots, and 500 mb temperatures around -14C. This
   could be enough for hail with the stronger cores. A few strong gusts
   may also occur.

   ...West Texas/Eastern New Mexico...
   Northwesterly flow at mid-levels is forecast on Tuesday across much
   of the Rockies and southern Plains. At the surface, an axis of
   maximized low-level moisture is forecast from southwest Texas
   extending northwestward into southeast New Mexico. Surface dewpoints
   near this axis will likely be in the lower 60s F, possibly yielding
   moderate instability by afternoon as surface temperatures warm. In
   spite of the lack of large-scale ascent, isolated thunderstorms
   appear likely to develop in the higher terrain. This convection will
   move into the lower elevations during the late afternoon. Steep
   low-level lapse rates, along with modest deep-layer shear may be
   enough for a marginal severe threat. Hail and strong gusts will be
   the primary hazards.

   ..Broyles.. 09/24/2023

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z