SPC AC 200538

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1238 AM CDT Wed Oct 20 2021

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
   OHIO INTO WESTERN PENNSYLVANIA AND FAR WESTERN NEW YORK AS WELL AS
   SOUTHERN OKLAHOMA...

   ...SUMMARY...
   A few showers/thunderstorms with gusty winds will be possible from
   eastern Ohio into western Pennsylvania Thursday afternoon. Isolated
   thunderstorms capable of marginally severe hail might occur late
   Thursday night over southern Oklahoma.

   ...Eastern Ohio and western Pennsylvania...

   Limited low-level moisture with a narrow corridor of mid 50s F
   dewpoints will return through the pre-frontal warm sector from OH
   into western PA. Forcing for ascent accompanying a progressive
   shortwave trough and its attendant cold front will move through the
   OH Valley during the day. Low-topped convection is expected to
   develop within the narrow corridor of very weak instability (less
   than 400 J/kg MUCAPE) along and just ahead of the front. Activity
   will be embedded within strong unidirectional southwesterly winds.
   Some potential will exist for higher momentum air to be transported
   to the surface within some of the rain cores. However, any severe
   threat should remain limited by the very marginal thermodynamic
   environment.

   ...Southern Oklahoma...

   A cold front is expected to stall in vicinity of the OK/TX border.
   Partially modified Gulf air will return northward beneath 6.5 - 7
   C/km mid-level lapse rates, resulting in up to 1000 J/kg MUCAPE from
   northwest TX into southern OK overnight. Some uncertainty exists
   regarding extent of thunderstorm initiation, but modest isentropic
   ascent north of this boundary might contribute to the development of
   a few thunderstorms very late in the period, and some of these
   updrafts might become capable of producing a few instances of
   marginally severe hail.

   ..Dial.. 10/20/2021

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z