SPC AC 240653

   Day 1 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0153 AM CDT Sun May 24 2020

   Valid 241200Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
   MINNESOTA TO SOUTH TEXAS...

   CORRECTED FOR TORNADO GRAPHIC

   ...SUMMARY...
   Severe thunderstorms are possible from Texas to southern Minnesota.
   Large hail and damaging wind gusts are the primary severe threats.

   ...Discussion...

   Broad upper troughing will remain centered over the Rockies through
   the day1 period, though a few notable short-wave troughs will eject
   into the mid-continent region. Each of these short waves should
   prove efficient in generating deep convective clusters capable of
   producing hail and wind.

   The northernmost feature is forecast to eject into the upper MS
   Valley early in the period, then short-wave ridging will result in
   height rises from the eastern Dakotas into the upper Great Lakes
   region. In response to the short-wave trough, deep convection, with
   some severe threat, will be ongoing at the start of the period
   across southwestern MN into western IA. This activity will likely be
   an extension of the current MCS that is located over SD/NE at 0630z.
   Models are not particularly aggressive with air-mass destabilization
   ahead of this thunderstorm cluster and daytime weakening is possible
   as the remnant MCS shifts into the upper Great Lakes region. In the
   wake of the short-wave trough, large-scale forcing for ascent will
   be notably absent with only frontal convergence and daytime heating
   expected. Forecast soundings suggest surface temperatures will warm
   into the upper 70s/80F across western IA into southeastern NE which
   should be adequate for parcels to reach their convective
   temperatures. As a result, isolated thunderstorms should redevelop
   along the frontal zone then track northeast within a modestly
   sheared environment. While a few weak supercells can not be ruled
   out, wind profiles favor mixed storm modes that could produce
   wind/hail.

   Farther south across the southern High Plains, strongest
   boundary-layer heating will be noted across eastern NM into far west
   TX, along/west of a sharp dry line. Robust thunderstorm development
   is expected along the dry line by 21z as inhibition is removed ahead
   of low-latitude short-wave trough that should extend from NM into
   northern Mexico by early afternoon. While wind profiles will likely
   be a bit weak for supercells, extreme buoyancy may allow a few weak
   supercells to develop early in the convective cycle. Subsequent
   large-scale forcing should encourage significant upward-evolving
   thunderstorm clusters by early evening. This activity is expected to
   propagate east-southeast. Organized deep convection may spread into
   south-central TX, possibly reaching the middle TX Coast by the end
   of the period. Large hail should be common early in the convective
   cycle, shifting to more of a wind threat as the MCS grows upscale
   after sunset.

   ...South Florida...

   Low-level shear is forecast to increase markedly across the FL Keys
   into portions of southwestern FL during the latter half of the
   period. This increase in shear is due to developing wave over the
   southeastern Gulf Basin that should drift north through the period.
   Have introduced low tornado probabilities to reflect this evolving
   low-pressure system.

   ..Darrow/Lyons.. 05/24/2020

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z