May 28, 2009 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Thu May 28 07:29:37 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20090528 0730 UTC Day 3 Outlook Graphic
Probabilistic Graphic
20090528 0730 UTC Day Probabilitic Graphic
Probability Legend Image
   SPC AC 280726
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0226 AM CDT THU MAY 28 2009
   
   VALID 301200Z - 311200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   LARGE UPPER TROUGH OVER ERN NOAM IS FORECAST TO SHIFT EWD WITH TIME
   THIS PERIOD...WHILE ASSOCIATED SURFACE FRONT LINGERS OVER THE FL
   VICINITY.  MEANWHILE...NW FLOW ALOFT WILL PERSIST ACROSS THE CENTRAL
   PART OF THE COUNTRY ON THE BACK SIDE OF THE ERN U.S. TROUGH...WITH A
   NW-SE BAROCLINIC ZONE OVER THE CENTRAL U.S. FORECAST TO LINGER --
   AND EVENTUALLY SHIFT NWD -- THROUGH THE END OF THE PERIOD.
   
   ...SD/NEB ACROSS THE MID AND LOWER MO/MID MS/LOWER OH VALLEYS...
   SIMILAR SCENARIO IS FORECAST DAY 3 AS THAT FOR DAY 2...IN THAT
   ISOLATED STORMS SHOULD REDEVELOP INVOF THE SURFACE BOUNDARY AND THEN
   SHIFT SEWD WITHIN MEAN NWLYS.  SEVERAL QUESTIONS LOOM THIS
   PERIOD...INCLUDING EXACT POSITION OF THE SURFACE FRONT AND WHETHER
   STRONGER FLOW ALOFT REMAINS NEAR THE FRONT...OR MORE TO THE COOL
   SIDE OF THE BOUNDARY.  THE GFS PLACES THE FRONT ACROSS THE MID AND
   LOWER MO VALLEY BY AFTERNOON...WHILE THE NAM DEVELOPS A SECONDARY
   W-E BOUNDARY ACROSS KS.  
   
   DUE TO THIS UNCERTAINTY...WILL MAINTAIN A LARGE -- BUT AT THIS TIME
   LOW PROBABILITY -- THREAT AREA FROM PARTS OF SD/NEB SEWD INTO THE
   MID MS AND LOWER OH VALLEYS...TO COVER SEVERE POTENTIAL WITH STORMS
   DEVELOPING INVOF THE SURFACE FRONT AND PERHAPS EVOLVING INTO ONE OR
   MORE FORWARD/SEWD-PROPAGATING CONVECTIVE CLUSTERS DURING THE
   EVENING.  
   
   ...FL...
   SURFACE FRONT LINGERING SOMEWHERE INVOF N FL SUGGESTS THAT A
   MOIST/UNSTABLE AIRMASS ACROSS FL WILL SUPPORT THE DEVELOPMENT OF
   SHOWERS AND THUNDERSTORMS -- BOTH NEAR THE SURFACE FRONT AND OTHER
   LOW-LEVEL/SEA-BREEZE BOUNDARIES.  WITH A BELT OF MODEST WLYS ALOFT
   FORECAST ACROSS FL...POTENTIAL EXISTS FOR A FEW STRONGER CELLS...AND
   THUS WILL INTRODUCE 5% SEVERE PROBABILITY ACROSS MOST OF THE
   PENINSULA.
   
   ..GOSS.. 05/28/2009
   
   CLICK TO GET WUUS03 PTSDY3 PRODUCT

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