Dec 21, 2021 0100 UTC Day 1 Convective Outlook
Updated: Tue Dec 21 00:34:53 UTC 2021 (20211221 0100Z Day 1 shapefile | 20211221 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211221 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20211221 0100 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20211221 0100 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20211221 0100 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 210034

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0634 PM CST Mon Dec 20 2021

   Valid 210100Z - 211200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Severe thunderstorms are not expected through tonight.

   ...FL Peninsula...

   Strong southern-stream short-wave trough has progressed to near the
   Sabine River with an upper low now positioned over the Arklatex.
   Deep, organized convection is currently suppressed across the
   southern Gulf Basin where greater buoyancy is supporting deep
   updrafts and lightning. Later tonight, 500mb flow is forecast to
   strengthen west of the central FL Peninsula which will encourage a
   notable surface low to track to near the Gulf Coast just west of
   TPA. Current forecast is for the more buoyant air mass to remain
   offshore until near sunrise. As higher low-level moisture advances
   inland just ahead of the low, instability is expected to become more
   supportive of potentially strong, organized updrafts. Forecast
   soundings, however, suggest the more appreciable severe threat will
   materialize just after 21/12z, and for this reason will not
   introduce severe probabilities at this time. Even so, strong
   convection will likely be approaching the FL Gulf Coast by the end
   of the day1 period.

   ..Darrow.. 12/21/2021

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z