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Day 4-8 Severe Weather Outlook Issued on Sep 4, 2012
Updated: Tue Sep 4 08:59:03 UTC 2012
Day 4-8 Severe Weather Outlook Graphics Issued on Sep 4, 2012
D4Fri, Sep 07, 2012 - Sat, Sep 08, 2012 D7Mon, Sep 10, 2012 - Tue, Sep 11, 2012
D5Sat, Sep 08, 2012 - Sun, Sep 09, 2012 D8Tue, Sep 11, 2012 - Wed, Sep 12, 2012
D6Sun, Sep 09, 2012 - Mon, Sep 10, 2012 (All days are valid from 12 UTC - 12 UTC)
Note: A severe weather area depicted in the Day 4-8 period indicates a 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).

 Forecast Discussion

   ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 040857
   SPC AC 040857
   
   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0357 AM CDT TUE SEP 04 2012
   
   VALID 071200Z - 121200Z
   
   ...DISCUSSION...
   GFS AND ECMWF IN DECENT AGREEMENT ATTM THROUGH DAY 5 /SAT
   9-8/...BRINGING A DIGGING/POSITIVELY TILTED UPPER SHORT-WAVE TROUGH
   SEWD ACROSS UPPER MS VALLEY REGION AND PLAINS STATES DAY 4 /FRI
   9-8/...AND THEN INTO THE MID-SOUTH REGION DAY 5 WHERE IT SLOWS AND
   DEEPENS INTO A CLOSED LOW.
   
   AFTER DAY 5...MODELS BEGIN DIFFERING AS THE ECMWF CONTINUES TO
   DEEPEN THE LOW -- SHIFTING IT SLOWLY NEWD TOWARD THE MID-ATLANTIC
   REGION THROUGH THE REMAINDER OF THE PERIOD.  MEANWHILE THE GFS
   DEPICTS A WEAKENING/OPENING FEATURE THAT EVENTUALLY SHIFTS OFFSHORE
   INTO THE ATLANTIC.  
   
   SOME SEVERE POTENTIAL WILL LIKELY ACCOMPANY THE DIGGING TROUGH AND
   ASSOCIATED/SEWD-MOVING COLD FRONT AS THEY MOVE ACROSS THE CENTRAL
   U.S. DAY 4.  WITH AMPLY UNSTABLE WARM SECTOR AND MODERATE WNWLYS AT
   MID LEVELS...THE ENVIRONMENT SHOULD BE SUPPORTIVE FOR AT LEAST
   ISOLATED STRONGER/SEVERE STORMS.  HOWEVER...COVERAGE/INTENSITY
   ANTICIPATED DOES NOT ATTM WARRANT INTRODUCTION OF A THREAT AREA.  
   
   A MORE LIMITED THREAT MAY CONTINUE INTO DAY 5...AS THE SURFACE FRONT
   SHIFTS QUICKLY SEWD ACROSS THE MID SOUTH/SOUTHEAST.  BEYOND THIS
   TIME...COMBINATION OF MODEL UNCERTAINTY AND WHAT APPEARS OVERALL TO
   BE A PATTERN UNFAVORABLE FOR WIDESPREAD SEVERE STORMS PRECLUDES
   CONSIDERATION OF ANY AREAL HIGHLIGHTS THROUGH THE REMAINDER OF THE
   PERIOD.
   
   ..GOSS.. 09/04/2012

   CLICK TO GET WUUS48 PTSD48 PRODUCT

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