Jan 9, 2020 0830 UTC Day 3 Severe Thunderstorm Outlook
Updated: Thu Jan 9 08:29:51 UTC 2020 (20200109 0830Z Day 3 shapefile | 20200109 0830Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200109 0830 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 103,954 8,887,867 New Orleans, LA...Birmingham, AL...Baton Rouge, LA...Montgomery, AL...Mobile, AL...
SLIGHT 61,744 8,917,575 Atlanta, GA...Columbus, GA...Huntsville, AL...Tallahassee, FL...Lafayette, LA...
MARGINAL 135,789 20,126,641 Memphis, TN...Charlotte, NC...Nashville, TN...Raleigh, NC...Greensboro, NC...
Probabilistic Graphic
20200109 0830 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 88,219 8,065,335 New Orleans, LA...Birmingham, AL...Baton Rouge, LA...Montgomery, AL...Mobile, AL...
30 % 103,631 8,868,961 New Orleans, LA...Birmingham, AL...Baton Rouge, LA...Montgomery, AL...Mobile, AL...
15 % 62,073 9,043,183 Atlanta, GA...Columbus, GA...Huntsville, AL...Tallahassee, FL...Lafayette, LA...
5 % 135,562 20,008,602 Memphis, TN...Charlotte, NC...Nashville, TN...Raleigh, NC...Greensboro, NC...
   SPC AC 090829

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CST Thu Jan 09 2020

   Valid 111200Z - 121200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
   LA...SOUTHERN AND CENTRAL MS/AL AND THE WESTERN FL PANHANDLE...

   ...SUMMARY...
   Severe thunderstorms capable of damaging winds and tornadoes are
   expected across parts of the southeastern U.S. on Saturday.

   ...Lower MS Valley through the Southeast States...

   The intense southern Plains shortwave trough will lift northeast
   across the mid/lower MS Valley through Saturday afternoon, spreading
   a 100+ kt southwesterly 500 mb jet streak across the region. A 60+
   kt south/southwesterly low level jet will already be in place across
   much of the Deep South into the Ohio Valley Saturday morning.
   Intense vertical shear will help to maintain a QLCS from the Day 2
   period, which will be oriented along a cold front extending
   southward from a surface low from eastern AR into south-central LA
   at the beginning of the period. Ahead of the QLCS, rich boundary
   layer moisture with dewpoints in the upper 60s to near 70 F will
   reside as far north as northern MS/AL, with low 60s F as far north
   as the lower OH Valley. Given the strength of deep layer flow,
   strong, damaging winds are expected to spread eastward across
   eastern LA and much of MS/AL and the western FL Panhandle through
   late afternoon/early evening. Backed low level flow and at least 500
   J/kg MLCAPE should support mesovortex tornadoes as well, especially
   across southeast LA into southern/central MS/AL and the western FL
   Panhandle. 

   It remains uncertain how pristine the warm sector will remain ahead
   of the QLCS and this will impact how much, if any, pre-frontal
   semi-discrete convection develops. That being said, a conditional
   threat for supercells and accompanying tornadoes (some possibly
   strong) will exist across the Enhanced risk area, in addition to the
   QLCS-related threats. 

   With northward extent, instability will quickly diminish across TN
   into the lower OH Valley, but the intense wind field will support at
   least a low-end damaging wind threat into parts of southern KY. The
   QLCS likewise should weaken as it tracks eastward into GA Saturday
   night, but weak instability and continued strong vertical shear
   could support at least low-end severe potential as the front shifts
   east into the Carolinas overnight into early Sunday morning.

   ..Leitman.. 01/09/2020

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0830Z