SPC AC 170730

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0230 AM CDT Sun Sep 17 2023

   Valid 191200Z - 201200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTHWEST TEXAS
   INTO WESTERN AND CENTRAL OKLAHOMA...

   ...SUMMARY...
   Widely scattered severe thunderstorms are possible Tuesday and
   Tuesday night across portions of the southern Great Plains.  Large
   to very large hail and severe gusts are the primary hazards.

   ...TX northward into southern KS...
   A weak mid-level disturbance, initially over the CO/northern NM
   vicinity, will move east-southeastward into OK by early evening and
   be to the north of a flattened mid-level anticyclone over Mexico. 
   Isolated showers/thunderstorms may be ongoing Tuesday morning across
   parts of OK/KS in association with a 40-kt south-southwesterly LLJ. 
   Models vary regarding the details and subsequent evolution of this
   potential convective activity during the day.  Regardless, southerly
   low-level flow east of a lee trough/sharpening dryline will favor
   increasing moisture across northwest TX into western OK (surface
   dewpoints into the 56-62 deg F range).  An appreciable westerly
   component of the flow in the midlevels will aid in eastward
   advection of steeper lapse rates.  Strong heating in areas void of
   cloud debris/early day storms will likely become moderately unstable
   (1000-2500 J/kg MLCAPE).  Elongated hodographs due to the proximity
   of a 75-100 kt 250 mb jet over the TX Panhandle/northwest TX will
   favor organized storms, including the possibility for supercells. 
   It seems the dryline will probably serve as a focus for isolated to
   scattered thunderstorm development on Tuesday afternoon.  Large to
   very large hail and severe gusts are the primary hazards.  A
   strengthening LLJ during the evening centered over the Red River
   Valley will probably lead to some upscale growth in the form of a
   strong/severe cluster.  This activity may continue into early
   Wednesday with a lingering risk for severe.

   ..Smith.. 09/17/2023

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