Dec 23, 2020 1630 UTC Day 1 Convective Outlook
Updated: Wed Dec 23 16:30:58 UTC 2020 (20201223 1630Z Day 1 shapefile | 20201223 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20201223 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 42,851 5,016,283 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Lafayette, LA...
MARGINAL 108,852 7,465,242 Memphis, TN...Shreveport, LA...Jackson, MS...Pasadena, TX...Beaumont, TX...
Probabilistic Tornado Graphic
20201223 1630 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
5 % 41,468 4,951,997 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Lafayette, LA...
2 % 88,965 5,445,385 Shreveport, LA...Jackson, MS...Pasadena, TX...Beaumont, TX...Baytown, TX...
Probabilistic Damaging Wind Graphic
20201223 1630 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
15 % 42,489 4,985,982 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Lafayette, LA...
5 % 108,977 7,414,319 Memphis, TN...Shreveport, LA...Jackson, MS...Pasadena, TX...Beaumont, TX...
Probabilistic Large Hail Graphic
20201223 1630 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
5 % 35,025 3,130,562 Pasadena, TX...Lafayette, LA...Beaumont, TX...Lake Charles, LA...Baytown, TX...
   SPC AC 231630

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1030 AM CST Wed Dec 23 2020

   Valid 231630Z - 241200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
   MISSISSIPPI VALLEY/GULF COAST STATES...

   ...SUMMARY...
   A threat for damaging wind gusts and a few tornadoes will shift
   eastward across the Lower Mississippi Valley and central Gulf Coast
   region this afternoon through tonight.

   ...Lower Mississippi Valley/Gulf Coast States...
   Steady height falls are expected today as a
   base-embedded/positive-tilt portion of an upper trough spreads
   toward the ArkLaTex/Lower Mississippi Valley through tonight, with a
   cold front moving southeastward across the region. 

   Within the warm sector, showers/some thunderstorms should gradually
   increase this afternoon from the middle/upper Texas coast into
   Louisiana. Although cloud cover may remain semi-prevalent ahead of
   the cold front, a moistening/warming boundary layer and gradual
   erosion of convective inhibition suggests that this activity may
   gradually become more surface-based and potentially intensify as
   early as mid/late afternoon, although the cloud cover/initially
   modest forcing for ascent are points of temporal uncertainty. 

   Another zone of intensifying thunderstorm development is expected
   immediately near the cold front as it moves southeastward across the
   ArkLaTex/Mid-South late this afternoon/early evening.
   Moisture/buoyancy will be comparatively lesser with northward
   extend, but with very strong southwesterly winds through a deep
   layer, at least some potential for damaging winds/possibly a brief
   tornado will exist with near-surface-based storms late this
   afternoon into tonight.

   Overall, convection will become increasing prevalent/organized this
   evening, including linearly organized convection near the cold front
   as well as front/line-preceding semi-discrete development including
   supercells, with all of this activity tending to merge overnight.
   Damaging winds and a couple of tornadoes will be possible,
   particularly across parts of Louisiana and far southern Mississippi.
   A severe risk may exist as far east as the Florida
   Panhandle/southern Alabama late tonight into early Thursday.

   ..Guyer/Lyons.. 12/23/2020

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z