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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Sep 2, 2014
Updated: Tue Sep 2 08:26:33 UTC 2014
D4-8 D4 D5 D6 D7 D8
 Population  Cities/Towns  CWAs  Interstates  Counties  FEMA Regions

Severe Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4Fri, Sep 05, 2014 - Sat, Sep 06, 2014 D7Mon, Sep 08, 2014 - Tue, Sep 09, 2014
D5Sat, Sep 06, 2014 - Sun, Sep 07, 2014 D8Tue, Sep 09, 2014 - Wed, Sep 10, 2014
D6Sun, Sep 07, 2014 - Mon, Sep 08, 2014 (All days are valid from 12 UTC - 12 UTC the following day)
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 020826
   SPC AC 020826

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0326 AM CDT TUE SEP 02 2014

   VALID 051200Z - 101200Z

   ...DISCUSSION...
   ECMWF/GFS BOTH AGREE THAT UPPER GREAT LAKES SPEED MAX WILL EJECT
   ACROSS ONTARIO INTO QUEBEC DURING THE DAY4 PERIOD...WELL NORTH OF
   THE INTERNATIONAL BORDER.  THIS EVOLUTION WILL FORCE A SFC FRONT
   INTO NY...WHILE A MUCH WEAKER BOUNDARY SHOULD TRAIL ACROSS THE OH
   VALLEY.  CONVECTION IS EXPECTED TO DEVELOP ALONG THIS WIND SHIFT BUT
   LATEST GUIDANCE SUGGESTS THE STRONGEST DEEP LAYER SHEAR WILL LAG THE
   FRONTAL ZONE SUCH THAT TSTMS THAT EVOLVE SHOULD BE MORE
   MULTI-CELLULAR IN NATURE AND POSSIBLY LESS ORGANIZED.  BEYOND THE
   DAY4 PERIOD...MEANINGFUL INSTABILITY WILL BE DISPLACED WELL SOUTH OF
   STRONGER FLOW ALOFT AND SEVERE PREDICTABILITY WILL LESSON
   CONSIDERABLY.

   ..DARROW.. 09/02/2014

   CLICK TO GET WUUS48 PTSD48 PRODUCT


To retrieve previous Day 4-8 convective outlooks, enter the date YYYYMMDD (e.g., 20050310 for March 10, 2005.)
Data available since March 8, 2005.
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Page last modified: September 02, 2014
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