Dec 19, 2021 2000 UTC Day 1 Convective Outlook
Updated: Sun Dec 19 19:35:39 UTC 2021 (20211219 2000Z Day 1 shapefile | 20211219 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211219 2000 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
20211219 2000 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
20211219 2000 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
20211219 2000 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 191935

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0135 PM CST Sun Dec 19 2021

   Valid 192000Z - 201200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

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

   ...20Z Outlook Update...
   Modest to weak pre-frontal flow near the surface through around 850
   mb has gradually veered to an increasing westerly component across
   much of Florida.  An area of scattered weak, but deepening,
   convection is evident just ahead of the front, to the west and
   southwest of the Jacksonville area.  This seems to provide the
   primary lingering risk for renewed thunderstorm development, with a
   moist boundary layer across northern Atlantic coastal areas (as far
   south as Daytona Beach) now appearing characterized by moderate CAPE
   on the order of 1500 J/kg.  However, large-scale forcing for ascent
   is generally weak, and remaining risk for thunderstorms probably
   will diminish after 00Z.

   ..Kerr.. 12/19/2021

   .PREV DISCUSSION... /ISSUED 1027 AM CST Sun Dec 19 2021/

   ...Northern Florida/southeast Georgia...
   A moist and modestly unstable air mass precedes an
   east/southeastward-advancing cold front. Widely scattered showers
   and thunderstorms will remain a possibility, with the potential for
   thunderstorms to redevelop along the front this afternoon in the
   wake of more prevalent activity in the predawn hours. While a strong
   wind gust or two could occur, the potential for severe-caliber
   storms is likely to remain minimal given weak lapse rates aloft and
   the marginality of overall buoyancy. 

   ...South Texas...
   As per the 12Z observed sounding from Brownsville, thermodynamic
   profiles ahead of an approaching upper trough over northern Mexico
   will be marginally supportive of isolated elevated thunderstorms
   today into tonight, particularly in closer proximity to the Rio
   Grande.

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z