Sep 9, 2017 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Sat Sep 9 07:16:27 UTC 2017 (20170909 0730Z Day 3 shapefile | 20170909 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170909 0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 81,149 10,831,178 Jacksonville, FL...Savannah, GA...Gainesville, FL...Fayetteville, NC...Columbia, SC...
Probabilistic Graphic
20170909 0730 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
5 % 80,574 11,041,782 Jacksonville, FL...Savannah, GA...Gainesville, FL...Fayetteville, NC...Columbia, SC...
   SPC AC 090716

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0216 AM CDT Sat Sep 09 2017

   Valid 111200Z - 121200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
   FL INTO SOUTHEAST NC...

   ...SUMMARY...
   Brief tornadoes are possible Monday from northwest Florida into
   southeast North Carolina as Irma moves through the Southeast.

   ...Synopsis...
   Current forecast track for Hurricane Irma takes the system from the
   northern FL Peninsula northwestward into central AL/GA during the
   period. Significant weakening is anticipated during this time,
   particularly during the second half of the period, but the expansive
   wind field associated with Irma is still expected to remain strong
   enough to support a tornado threat (more details below). 

   Elsewhere, upper ridging centered over the Four Corners will remain
   relatively unchanged and the upper low off the southern CA coast
   will slowly drift northeastward. 

   ...Northeast FL/Eastern GA/Eastern SC/Southeast NC...
   Despite the anticipated northwestward movement of Irma, the tornado
   threat is expected to remain somewhat closer to the coast where
   dewpoints in the 70s and diurnal cloud breaks are most likely. Given
   the moist atmospheric profiles and resulting weak lapse rates, these
   higher dewpoints are needed to support even modest instability. This
   instability will be co-located with strong low-level shear,
   resulting in the threat for brief tornadoes.

   ..Mosier.. 09/09/2017

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z