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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Apr 18, 2014
Updated: Fri Apr 18 08:32:04 UTC 2014
D4-8 D4 D5 D6 D7 D8
 Population  Cities/Towns  CWAs  Interstates  Counties  FEMA Regions

Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4Mon, Apr 21, 2014 - Tue, Apr 22, 2014 D7Thu, Apr 24, 2014 - Fri, Apr 25, 2014
D5Tue, Apr 22, 2014 - Wed, Apr 23, 2014 D8Fri, Apr 25, 2014 - Sat, Apr 26, 2014
D6Wed, Apr 23, 2014 - Thu, Apr 24, 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 180831
   SPC AC 180831

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0331 AM CDT FRI APR 18 2014

   VALID 211200Z - 261200Z

   ...DISCUSSION...
   EARLY IN THE MEDIUM-RANGE PERIOD BOTH THE GFS AND ECMWF ARE IN
   GENERAL AGREEMENT REGARDING THE MOVEMENT OF LOW-LATITUDE SHORT-WAVE
   TROUGH AS IT SHIFTS EAST OF THE SRN PLAINS INTO THE LOWER MS VALLEY.
   25-35KT NW H5 FLOW ON BACK SIDE-BASE OF THIS FEATURE WILL ENHANCE
   DEEP-LAYER SHEAR COINCIDENT WITH MODEST INSTABILITY.  STRONG HEATING
   WILL LIKELY DEVELOP ACROSS THE HILL COUNTRY OF TX AND DAYTIME
   HEATING COULD PROVE INSTRUMENTAL IN A FEW SUPERCELLS IN THE WAKE OF
   SHORT WAVE.  GIVEN THAT THIS ACTIVITY WOULD EVOLVE WITHIN A BROADER
   ZONE OF LESS THAN FAVORABLE LARGE-SCALE ASCENT...COVERAGE SHOULD BE
   INADEQUATE TO WARRANT 30 PERCENT SEVERE PROBS DURING THE DAY4
   PERIOD.

   LATER IN THE WEEK MODEL SOLUTIONS BEGIN TO DIVERGE A BIT AS
   LARGE-SCALE PATTERN CHANGES.  ECMWF IS CONSIDERABLY FASTER THAN THE
   GFS ALLOWING A STRONG SHORT-WAVE TROUGH TO TRANSLATE INTO THE
   ROCKIES BY WEDNESDAY.  DIFLUENT FLOW ALOFT AND STRENGTHENING SHEAR
   PROFILES WOULD PROVE POTENTIALLY FAVORABLE FOR A PLAINS SEVERE
   EVENT.  HOWEVER...GFS DOES NOT EJECT THIS FEATURE UNTIL LATER
   THURSDAY.  EITHER OF THESE SOLUTIONS COULD GENERATE A POTENTIALLY
   SIGNIFICANT SEVERE EVENT BUT TIMING DIFFERENCES PREVENT DELINEATING
   AN ORGANIZED SEVERE THREAT THIS PERIOD.

   ..DARROW.. 04/18/2014

   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: April 18, 2014
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