Nov 20, 2018 0830 UTC Day 3 Severe Thunderstorm Outlook
Updated: Tue Nov 20 08:19:57 UTC 2018 (20181120 0830Z Day 3 shapefile | 20181120 0830Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0830 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Graphic
20181120 0830 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 200819

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0219 AM CST Tue Nov 20 2018

   Valid 221200Z - 231200Z


   Severe thunderstorms are not expected on Thursday.

   ...Synopsis and Discussion...
   A progressive shortwave trough is expected to move eastward from its
   early period position over the western Great Basin to the
   central/southern Plains by 12Z Friday. Lee cyclogenesis is
   anticipated ahead of this shortwave across the central High Plains,
   with the resulting surface low likely located near the western KS/OK
   by the end of the period. Enhanced surface pressure gradient between
   this low and its associated troughing across the Plains and high
   pressure over the Northeast will result in southerly wind across the
   southern Plains throughout much the period. Even so, winds across
   the Gulf will remain predominately easterly until after 00Z Friday,
   limiting moisture return and keeping the air mass stable.
   Consequently, thunderstorm development is not anticipated during the
   period across the southern Plains.

   The best chance for thunderstorms appears to be off of the northeast
   FL/southeast GA coast where a low-amplitude shortwave will interact
   with moist and marginally unstable air mass. Highest coverage will
   be offshore with inland areas having thunderstorm probabilities of
   less than 10%.

   ..Mosier.. 11/20/2018