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Day 4-8 Severe Weather Outlook Issued on Aug 8, 2011
Updated: Mon Aug 8 08:35:03 UTC 2011
Day 4-8 Severe Weather Outlook Graphics Issued on Aug 8, 2011
D4Thu, Aug 11, 2011 - Fri, Aug 12, 2011 D7Sun, Aug 14, 2011 - Mon, Aug 15, 2011
D5Fri, Aug 12, 2011 - Sat, Aug 13, 2011 D8Mon, Aug 15, 2011 - Tue, Aug 16, 2011
D6Sat, Aug 13, 2011 - Sun, Aug 14, 2011 (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 080834
   SPC AC 080834
   
   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0334 AM CDT MON AUG 08 2011
   
   VALID 111200Z - 161200Z
   
   ...DISCUSSION...
   
   MODEL CONSENSUS IS THAT UPPER TROUGH OVER THE ERN U.S. WILL BEGIN TO
   DEAMPLIFY BY DAY 4 AND TRENDING TO A RESUMPTION OF A QUASI-ZONAL
   FLOW PATTERN WITH EMBEDDED PROGRESSIVE IMPULSES. ONE SUCH SHORTWAVE
   TROUGH WILL LIKELY ADVANCE INTO THE NRN PLAINS DAY 4 AND UPPER MS
   VALLEY REGION DAY 5. MODEST TIMING AND AMPLITUDE DIFFERENCES EXIST
   BETWEEN THE GFS AND ECMWF. RICHER MOISTURE WILL REMAIN SOUTH OF THE
   QUASISTATIONARY FRONT ACROSS THE SERN STATES. HOWEVER...MODIFIED CP
   AIR WILL BEGIN RETURNING NWD AHEAD OF TROUGH INTO THE NRN PLAINS DAY
   4 RESULTING IN A MARGINALLY TO MODERATELY UNSTABLE WARM SECTOR. A
   FEW STRONG TO SEVERE STORMS MAY DEVELOP ALONG ATTENDANT FRONT DAY
   4...BUT QUALITY OF MOISTURE RETURN LOWERS OVERALL CONFIDENCE IN A
   HIGHER PROBABILITY SEVERE THREAT AREA.
   
   A GREATER SEVERE THREAT MAY DEVELOP OVER THE MID-UPPER MS VALLEY AND
   CNTRL PLAINS BY DAY 5 WHERE MORE TIME WILL EXIST FOR GREATER
   MOISTURE RETURN AHEAD OF THE IMPULSE.
   
   IF CONSISTENCY IS DEMONSTRATED REGARDING TIMING AND AMPLITUDE OF
   THIS WAVE DURING THE NEXT SET OF MODEL RUNS...THESE AREAS WILL
   LIKELY BE INCLUDED IN A CATEGORICAL RISK AREA IN THE NEXT DAY 3 AND
   4-8 UPDATES.
   
   ..DIAL.. 08/08/2011

   CLICK TO GET WUUS48 PTSD48 PRODUCT

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