Sep 21, 2014 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Sun Sep 21 07:22:48 UTC 2014 (20140921 0730Z Day 3 shapefile | 20140921 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0730 UTC Day 3 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Graphic
20140921 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.
Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 210722

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0222 AM CDT SUN SEP 21 2014

   VALID 231200Z - 241200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ON
   TUESDAY...PARTICULARLY ACROSS PARTS OF THE CENTRAL PLAINS...UPPER
   MIDWEST...AND SOUTHERN ROCKIES.

   ...SYNOPSIS...
   A SPLIT UPPER-FLOW PATTERN WILL UNDERGO A DEGREE OF AMPLIFICATION ON
   TUESDAY AS RELATIVELY WEAK WESTERLIES REMAIN OVER MOST OF THE CONUS.
   A REMNANT UPPER LOW/SHORTWAVE TROUGH ANTICIPATED TO BE OVER THE
   NORTH-CENTRAL HIGH PLAINS EARLY TUESDAY SHOULD CONTINUE TO MOVE
   NORTHEASTWARD AND WEAKEN OVER THE DAKOTAS/UPPER MIDWEST. ASSOCIATED
   WARM ADVECTION WILL CONTRIBUTE TO THUNDERSTORMS ACROSS THE CENTRAL
   PLAINS/UPPER MIDWEST BEGINNING EARLY IN THE PERIOD...WHILE OTHER
   THUNDERSTORMS /SOME POSSIBLY STRONG/ DEVELOP LATER IN THE DAY IN
   VICINITY OF A CENTRAL PLAINS LEE TROUGH. ELSEWHERE...NON-SEVERE
   THUNDERSTORMS WILL ALSO BE POSSIBLE ALONG/SOUTH OF A REMNANT FRONTAL
   ZONE ACROSS FL AND SOUTH TX.

   ...CENTRAL PLAINS...
   AFOREMENTIONED UPPER LOW/SHORTWAVE TROUGH SHOULD GENERALLY SPREAD
   NORTHEASTWARD AWAY FROM THE REGION DURING THE DAY...WITH RELATIVELY
   WEAK CYCLONIC WESTERLIES COINCIDENT WITH A LEE-SIDE SURFACE TROUGH.
   WHILE OVERALL FORCING WILL BE RELATIVELY WEAK...SUFFICIENT
   HEATING/CONVERGENCE NEAR THE LEE TROUGH COULD CONTRIBUTE TO ISOLATED
   SURFACE-BASED THUNDERSTORM DEVELOPMENT TUESDAY AFTERNOON/EARLY
   EVENING...POTENTIALLY INCLUDING AREAS SUCH AS WESTERN KS/SOUTHWEST
   NEB AND THE TX/OK PANHANDLES. CURRENT THINKING IS THAT MLCAPE COULD
   REACH 500-1000 J/KG BY PEAK HEATING IN VICINITY OF THE
   TROUGH...ALTHOUGH EFFECTIVE SHEAR SHOULD GENERALLY BE 30 KT OR LESS.
   WHILE A WEAK FORCING/VERTICAL SHEAR REGIME CURRENTLY PRECLUDES A
   SEVERE RISK...LOW SEVERE PROBABILITIES /RELATED TO HAIL POTENTIAL/
   COULD BE WARRANTED IN SUBSEQUENT OUTLOOKS.

   ..GUYER.. 09/21/2014

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