SPC AC 191730

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Thu Sep 19 2024

   Valid 201200Z - 211200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
   MIDWEST AND ALSO THE SOUTH-CENTRAL PLAINS...

   ...SUMMARY...
   Isolated strong to severe thunderstorms are possible in the late
   afternoon Friday in parts of Illinois, Indiana, and southwest Lower
   Michigan. Isolated strong to severe storms are also possible across
   parts of the south-central Plains.

   ...Midwest...
   A low-amplitude shortwave trough will pass across the Upper to
   central Great Lakes during the first half of the period. This will
   outpace a cold front that trails from a cyclone shifting northeast
   in MB, yielding a largely weakening to stalling front by Friday
   evening. Most guidance suggests at least isolated thunderstorms
   should form within a low-level warm conveyor ahead of the front,
   generally focused on a moderate buoyancy plume emanating northeast
   from parts of MO/AR. A fast westerly upper jet will further impinge
   on this portion of the front as well, favorably timed with peak
   boundary-layer heating. A few marginally severe storms may develop
   within this regime. Despite weak mid-level lapse rates, elongation
   of the mid to upper hodograph should support a threat for 1-1.5 inch
   hail, along with strong to marginally severe gusts from 45-60 mph.
   These threats should diminish quickly after sunset. 

   ...Southern KS/northern OK vicinity...
   A mid/upper-level shortwave trough is forecast to move slowly
   eastward across the Southwest on Friday. Farther east, a surface
   boundary initially draped from the lower MO Valley into southern
   KS/northern OK is forecast to lift northward as a warm front.
   Large-scale ascent across much of the Plains may remain relatively
   limited, outside of low-level warm advection near/north of the
   front. However, relatively strong heating along the western/northern
   periphery of returning low-level moisture could support thunderstorm
   development during the afternoon somewhere in the vicinity of
   southwest KS/northwest OK. Effective shear of 30-40 kt will support
   potential for somewhat organized convection. Strong to localized
   severe gusts may be the most likely hazard, but hail cannot be ruled
   out if any more discrete storms can move into an environment of
   greater moisture/instability. 

   ...New Mexico...
   Scattered thunderstorms will be possible across much of NM on
   Friday, in closer proximity to the approaching shortwave trough.
   While deep-layer shear will be rather strong, generally weak
   midlevel lapse rates and buoyancy may tend to limit the potential
   for more robust storms. If confidence increases regarding sufficient
   heating/destabilization, then severe probabilities may eventually be
   needed for parts of the region.

   ...Central Plains into the lower MO Valley...
   Guidance continues to vary regarding the potential for robust
   elevated convection Friday night into Saturday morning, within a
   low-level warm advection regime. Increasing elevated buoyancy and
   sufficient mid/upper-level flow could support a few stronger storms
   with hail potential, but confidence in sufficient coverage and a
   favored region for this potential is too low for probabilities at
   this time.

   ..Dean.. 09/19/2024

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