Dec 28, 2021 0600 UTC Day 1 Convective Outlook
Updated: Tue Dec 28 05:50:26 UTC 2021 (20211228 1200Z Day 1 shapefile | 20211228 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211228 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 17,582 2,426,149 Baton Rouge, LA...Metairie, LA...Lafayette, LA...Kenner, LA...New Iberia, LA...
Probabilistic Tornado Graphic
20211228 1200 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 % 17,611 2,472,816 Baton Rouge, LA...Metairie, LA...Lafayette, LA...Kenner, LA...New Iberia, LA...
Probabilistic Damaging Wind Graphic
20211228 1200 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 % 17,621 2,427,691 Baton Rouge, LA...Metairie, LA...Lafayette, LA...Kenner, LA...New Iberia, LA...
Probabilistic Large Hail Graphic
20211228 1200 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 % 17,581 2,434,524 Baton Rouge, LA...Metairie, LA...Lafayette, LA...Kenner, LA...New Iberia, LA...
   SPC AC 280550

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1150 PM CST Mon Dec 27 2021

   Valid 281200Z - 291200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE LOWER MISSISSIPPI VALLEY...

   ...SUMMARY...
   Thunderstorms associated with a marginal severe threat may develop
   today across parts of the lower Mississippi Valley. Hail and strong
   wind gusts will be the primary threats.

   ...Lower Mississippi Valley...
   West-southwest mid-level flow will be located across much of the
   central and eastern U.S today. At the surface, a moist airmass will
   be in place from the southern Plains eastward across the Gulf Coast
   States. A large area of high pressure will remain over a part of the
   western Atlantic into the central Gulf of Mexico. On the periphery
   of the high, an area of mid-level moisture will drift northward
   across the western Gulf of Mexico today, reaching the lower
   Mississippi Valley late this afternoon. As surface temperatures warm
   in the boundary-layer, isolated thunderstorm may develop in parts of
   lower Mississippi Valley. RAP forecast soundings for 00Z/Wednesday
   have MLCAPE in the 1000 to 1200 J/kg range across much of southeast
   Louisiana into southwest Mississippi. Thunderstorms that develop
   within this moderate instability will have access to moderate
   deep-layer shear and steep enough lapse rates for a marginal severe
   threat. 0-3 km storm relative helicities may reach 200 m2/s2 in the
   early evening as low-level flow increases suggesting a brief tornado
   will be possible with any cell that exhibits rotation. Strong wind
   gusts and hail may also occur.

   ..Broyles/Moore.. 12/28/2021

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z