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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Aug 30, 2014
Updated: Sat Aug 30 08:23:27 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
D4Tue, Sep 02, 2014 - Wed, Sep 03, 2014 D7Fri, Sep 05, 2014 - Sat, Sep 06, 2014
D5Wed, Sep 03, 2014 - Thu, Sep 04, 2014 D8Sat, Sep 06, 2014 - Sun, Sep 07, 2014
D6Thu, Sep 04, 2014 - Fri, Sep 05, 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 300823
   SPC AC 300823

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0323 AM CDT SAT AUG 30 2014

   VALID 021200Z - 071200Z

   ...DISCUSSION...
   PROGRESSION OF UPPER TROUGH FROM THE MS VALLEY INTO THE GREAT LAKES
   IS HANDLED A BIT DIFFERENT BETWEEN THE ECMWF AND GFS.  GFS IS
   NOTABLY FASTER THAN THE ECMWF WITH SHORT WAVE EJECTING ACROSS SRN
   ONTARIO INTO QUEBEC DURING THE DAY4 PERIOD.  EVEN SO IT APPEARS
   FRONTAL CONVERGENCE AND INSTABILITY SHOULD PROVE ADEQUATE FOR AT
   LEAST ISOLATED TSTMS...POTENTIALLY SEVERE...BENEATH MODEST MID-LEVEL
   FLOW.  ROBUST STORMS SHOULD DEVELOP ALONG THE ADVANCING FRONT FROM
   SERN CANADA...SWWD ACROSS THE OH VALLEY INTO THE LOWER MS VALLEY. 
   WILL NOT INTRODUCE 30 PERCENT SEVERE PROBS FOR THIS FRONTAL
   CONVECTION DUE TO UNCERTAINTY IN LARGE SCALE SUPPORT FROM
   AFOREMENTIONED SHORT WAVE AND SUBSEQUENT STORM COVERAGE.

   LATER IN THE MEDIUM RANGE PERIOD HIGH LEVEL FLOW BECOMES MORE ZONAL
   ACROSS THE NRN US.  IT/S LIKELY THAT SUFFICIENT MOISTURE/INSTABILITY
   ARE ABLE TO ADVECT BENEATH THIS STRONGER BELT OF WIND/SHEAR.  AT
   THAT TIME STRONG STORMS COULD EVOLVE BUT TOO MUCH UNCERTAINTY EXISTS
   TO ACCURATELY PREDICT TIME/PLACE FOR THIS ACTIVITY.

   ..DARROW.. 08/30/2014

   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: August 30, 2014
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