ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 230859
   SPC AC 230859

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0359 AM CDT Tue Apr 23 2024

   Valid 261200Z - 011200Z

   ...DISCUSSION...
   A complex but active pattern is expected from D4/Friday through
   D6/Sunday, as multiple mid/upper-level shortwave troughs impinge
   upon a moist and unstable environment extending from the
   southern/central Great Plains into parts of the Midwest and
   Mississippi Valley. 

   ...D4/Friday - Central/southern Plains into the mid MS Valley...
   A negatively tilted shortwave trough is forecast to move
   northeastward from the Great Plains toward the mid/upper MS Valley
   on Friday. Most guidance suggests that convection developing late in
   the D3/Thursday period will be ongoing Friday morning, potentially
   posing an organized severe threat as it moves eastward. The
   influence of early convection on warm sector evolution by Friday
   afternoon/evening remains uncertain, but in general, moderate
   destabilization will be possible along the Pacific front/dryline in
   the wake of early convection, with some intensification of early
   storms also possible farther east. Details regarding storm mode
   remain uncertain at this forecast range, but in general, severe
   storms capable of producing large hail, damaging winds, and a few
   tornadoes will be possible across a broad region from the eastern
   Great Plains into the mid MS Valley.

   ...D5/Saturday - Central/southern Plains into the Midwest/mid MS
   Valley...
   The negatively tilted shortwave trough and attendant occluding
   surface cyclone are forecast to gradually weaken as they move across
   the upper Great Lakes region on Saturday. Depending on timing of the
   departing cyclone and magnitude of diurnal destabilization, some
   severe-thunderstorm threat could evolve in advance of this system
   through the afternoon across parts of WI/IL into MI, but confidence
   remains too low to include 15% probabilities for this area.  

   Meanwhile, another strong shortwave trough is forecast to eject
   across parts of the central/southern Plains Saturday afternoon and
   evening, accompanied by strong surface cyclogenesis across the
   central High Plains. Moderate to locally strong instability may
   redevelop along/east of the dryline across central/western KS/OK
   into north TX, as low-level and deep-layer shear strengthen through
   the day. The synoptic pattern depicted by much of the extended-range
   guidance is suggestive of an active severe thunderstorm episode
   along/ahead of the dryline, though some guidance (notably recent
   runs of the ECMWF) suggest potential for early development across
   parts of OK/north TX, which could complicate the scenario by late
   afternoon/evening. Some severe threat could spread toward parts of
   the mid MS Valley late in the period. 

   ...D6/Sunday - ArkLaTex into parts of the Midwest...
   Predictability begins to decrease by late in the weekend, though in
   general, a mid/upper-level trough and attendant surface low are
   forecast to move from the central Plains toward the upper Great
   Lakes region. A corridor of severe thunderstorm potential is
   forecast to extend south-southwestward from the surface low, as a
   trailing cold front moves through a moist, unstable, and favorably
   sheared environment. A 15% area has been added where confidence is
   currently greatest in severe-thunderstorm potential Sunday afternoon
   and evening.

   ..Dean.. 04/23/2024

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