SPC AC 180605

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1205 AM CST Fri Dec 18 2020

   Valid 191200Z - 201200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   The risk for severe thunderstorms appears negligible across the
   U.S., Saturday through Saturday night.

   ...Synopsis and Discussion...
   A pair shortwave troughs, one initially extending across the Upper
   Midwest and the other extending from south-central KS back into TX
   Permian Basin, are forecast to be in place early Saturday morning.
   The northern shortwave is expected to move gradually eastward over
   the Upper Great Lakes and into southern Ontario. The southern
   shortwave is expected to move quickly eastward across the southern
   Plains, Lower MS Valley, and much of the Southeast. Another
   shortwave trough will likely begin the period over the northern
   Rockies before dropping quickly southeastward. This shortwave is
   forecast to reach the central Plains by early Sunday morning.

   Any thunderstorm potential across the CONUS will be associated with
   the southern shortwave moving across the southern Plains, Lower MS
   Valley, and Southeast. Cold front associated with this shortwave
   will likely extend from a weak low over southeast OK/northeast TX
   southwestward through the Edwards Plateau early Saturday morning.
   Modest moisture advection is anticipated ahead of this front through
   the early evening. During the evening, secondary cyclogenesis will
   occur along the Upper TX coast, limiting the northward moisture
   transport thereafter.

   Modest, predominately elevated, instability will likely contribute
   to isolated lightning strikes within the deeper cores over the warm
   sector. Given that the majority of this activity will be rooted
   around 850mb, the severe potential is expected to remain low. There
   is a low probability that surface-based storms could develop along
   the middle TX Coast ahead of the front. However, current expectation
   is that any surface-based development will occur offshore.

   ..Mosier.. 12/18/2020

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