SPC AC 240533

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1133 PM CST Mon Nov 23 2020

   Valid 241200Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHERN PLAINS...

   ...SUMMARY...
   Severe thunderstorms are possible late afternoon Tuesday into
   Tuesday night across portions of the southern/central Plains,
   Ozarks, Mid-South, and lower Mississippi Valley.  Large hail and
   severe gusts are the primary hazards.

   ...Central/Southern Plains to Lower MS Valley...

   Strong mid-level vort with an accompanying 90kt+ speed max are
   digging into the lower CO River Valley at 0530z. This feature will
   shift east into southern NM by 18z then into the southern High
   Plains by late afternoon. 120m 12hr height falls, along with a
   focused exit region of the aforementioned jet, suggest convection
   will develop by early afternoon along the front over the western
   OK/TX Panhandle region. Forecast soundings suggest the strongest
   boundary-layer heating will be noted across this region, and despite
   the relatively dry boundary layer, profiles exhibit more than
   adequate instability for surface-based convection along the front.
   RAP forecast sounding for DHT exhibits ~900 J/kg SBCAPE with steep
   lapse rates and -22C at 500mb. Hail production should be efficient
   with this activity, although it may be initially sub-severe.

   Late-evening surface data suggests mid 50s surface dew points are
   advancing north across the Edwards Plateau and this moisture plume
   should return across western OK prior to the main convective
   development. While large-scale forcing for ascent should ultimately
   lead to more organized line segments downstream, initial activity
   across the far northeastern TX Panhandle into northwestern OK should
   be supercellular in nature. This early activity could certainly
   produce very large hail before the convective mode is disrupted.
   Prior to this disruption, a few brief tornadoes are also possible.
   As large-scale forcing spreads across western OK, a more organized
   band of storms should evolve then propagate east with an attendant
   hail/wind threat. Given that the LLJ will be focused into northeast
   OK/Ozark Plateau region, the primary corridor for organized
   convection should spread north of I-40 across OK into this region.

   Farther south, it's not entirely clear how active the warm sector
   will be prior to the cold frontal passage across northeast TX into
   western AR. HRRR is the most aggressive high res model in generating
   discrete storms in the warm sector by 25/00z, then along the front
   as it advances into this more moist air mass. However, stronger
   forcing will remain north of this region and there is reason to
   believe convection may be a bit more isolated across this region.
   Will maintain MRGL Risk across this area due to uncertainty in storm
   coverage/intensity.

   ..Darrow/Squitieri.. 11/24/2020

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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