Dec 26, 2021 2000 UTC Day 1 Convective Outlook
Updated: Sun Dec 26 19:39:20 UTC 2021 (20211226 2000Z Day 1 shapefile | 20211226 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211226 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
20211226 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
20211226 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
20211226 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 261939

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0139 PM CST Sun Dec 26 2021

   Valid 262000Z - 271200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated thunderstorms remain possible today over parts of the
   central Rockies, and parts of the Midwest.

   ...Discussion...
   While the ongoing forecast generally reflects current expectations,
   a few changes have been made to the outlook.  The primary change has
   been removal of the thunder area from the Pacific Northwest coastal
   region, as risk for thunder appears to have diminished to below 10%
   coverage.  While a couple of flashes will remain possible through
   the period, coverage should remain minimal.

   Meanwhile, a few lightning flashes are currently observed in the
   northwestern Colorado area, and therefore -- while reduced in areal
   coverage -- a 10% thunder area including portions of Wyoming and
   Colorado is being maintained.

   Likewise, a thunder area is being maintained over the Midwest
   region.  Some trimming on the southern fringe of the area is being
   implemented, as most of the lightning potential will be limited to
   the zone of elevated convection north of the northward-advancing
   warm front.

   ..Goss.. 12/26/2021

   .PREV DISCUSSION... /ISSUED 1002 AM CST Sun Dec 26 2021/

   ...Pacific Northwest and Great Basin...
   Strong onshore flow and cold temperatures aloft are present once
   again today along the OR and northern CA coast.  This will maintain
   the risk of isolated lightning flashes through the forecast period
   in this region.  A few instances of lightning will also be possible
   in snow showers ahead of a cold front surging eastward across parts
   of UT/CO/WY.

   ...MS/OH Valleys...
   Low-level warm advection and lift is expected to intensify late this
   afternoon and early evening over parts of IA/MO/IL, resulting in
   isolated showers and thunderstorms.  The strongest cells in this
   initial activity could produce small hail, but no severe storms are
   anticipated.  Scattered thunderstorms will likely persist through
   the night and spread eastward into parts of IN/OH and Lower MI by
   Monday morning.

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