Dec 28, 2021 1630 UTC Day 1 Convective Outlook
Updated: Tue Dec 28 16:16:02 UTC 2021 (20211228 1630Z Day 1 shapefile | 20211228 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211228 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 25,926 3,105,691 Baton Rouge, LA...Jackson, MS...Metairie, LA...Lafayette, LA...Kenner, LA...
Probabilistic Tornado Graphic
20211228 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
2 % 25,955 3,159,194 Baton Rouge, LA...Jackson, MS...Metairie, LA...Lafayette, LA...Kenner, LA...
Probabilistic Damaging Wind Graphic
20211228 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
5 % 26,132 3,123,863 Baton Rouge, LA...Jackson, MS...Metairie, LA...Lafayette, LA...Kenner, LA...
Probabilistic Large Hail Graphic
20211228 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 % 25,974 3,108,999 Baton Rouge, LA...Jackson, MS...Metairie, LA...Lafayette, LA...Kenner, LA...
   SPC AC 281616

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1016 AM CST Tue Dec 28 2021

   Valid 281630Z - 291200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   AND EVENING OVER PORTIONS OF LOUISIANA AND MISSISSIPPI...

   ...SUMMARY...
   Marginally severe thunderstorms are possible this afternoon and
   evening over parts of the lower Mississippi Delta region.

   ...LA/MS...
   A broad area of warm/moist surface conditions are present today from
   east TX into the Mid-South, resulting in modest CAPE values over the
   region.  Large scale forcing for ascent across this region is weak,
   and a mid-level capping inversion is present.  This will greatly
   limit the extent of thunderstorm activity in most areas.  However,
   there is a corridor from southern LA into central MS were model
   guidance shows the capping inversion weakening through the day,
   leading to a few robust storms this afternoon and evening. 
   Low-level shear profiles in this region are relatively strong,
   suggesting some potential for rotating updrafts and a marginal risk
   of a tornado, wind gust or hail report.  Therefore will maintain the
   ongoing MRGL risk area with no changes.

   ...Lower OH Valley...
   Another area of some concern for gusty thunderstorm winds is over
   the lower OH Valley.  A band of fast-moving low-topped showers is
   expected to develop this afternoon over southeast MO and track
   across portions of southern IL, southern IN, and western/central KY.
   Forecast soundings suggest that weak thermodynamic profiles (MUCAPE
   only 100-200 J/kg) will limit the risk of lightning with this
   activity.  However, very strong wind fields may result in a few
   locally strong wind gusts with the more intense showers or isolated
   thunderstorms.  Given the uncertainty and weak CAPE fields, will
   maintain a less than 5% severe wind probability forecast.

   ..Hart/Squitieri.. 12/28/2021

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