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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Apr 18, 2015
Updated: Sat Apr 18 08:43:02 UTC 2015
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Tue, Apr 21, 2015 - Wed, Apr 22, 2015 D7Fri, Apr 24, 2015 - Sat, Apr 25, 2015
D5Wed, Apr 22, 2015 - Thu, Apr 23, 2015 D8Sat, Apr 25, 2015 - Sun, Apr 26, 2015
D6Thu, Apr 23, 2015 - Fri, Apr 24, 2015 (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 15%, 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 unlikely (i.e., less than 15%) for the forecast day.
 Forecast Discussion

   ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 180841
   SPC AC 180841

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0341 AM CDT SAT APR 18 2015

   VALID 211200Z - 261200Z

   ...DISCUSSION...
   THE MEDIUM-RANGE MODELS INCLUDING THE GFS AND ECMWF BEGIN THE DAY 4
   TO 8 PERIOD WITH A BROAD CYCLONIC FLOW PATTERN OVER THE ERN
   TWO-THIRDS OF THE NATION. THE MODELS KEEP THE SRN PLAINS RELATIVELY
   DRY ON TUESDAY/DAY 4 EXCEPT FOR IN SRN AND CNTRL TX WHERE ISOLATED
   SEVERE STORMS COULD DEVELOP TUESDAY AFTERNOON. ON WEDNESDAY/DAY
   5...THE GFS SOLUTION AND TO A LESSER EXTENT THE ECMWF...INCREASE
   LOW-LEVEL MOISTURE IN THE SRN PLAINS. BOTH SOLUTIONS HAVE AN
   UPPER-LEVEL RIDGE EXTENDING NWWD FROM THE SRN PLAINS INTO THE SRN
   ROCKIES AND SRN HIGH PLAINS. THIS COULD HELP TO KEEP THE SEVERE
   THREAT ISOLATED ACROSS THE REGION WEDNESDAY AFTERNOON. BOTH
   SOLUTIONS REMAIN IN REMARKABLY GOOD AGREEMENT AT UPPER LEVELS BUT
   DIFFER ON WHERE THE MOIST AXIS WILL BE ON THURSDAY/DAY 6. THE
   POTENTIAL FOR SEVERE STORMS LOOKS GREATER ON THURSDAY DUE A
   MID-LEVEL JET MOVING INTO THE SRN PLAINS THURSDAY EVENING. SEVERE
   STORMS WITH LARGE HAIL...WIND DAMAGE AND POSSIBLY A FEW TORNADOES
   WILL BE POSSIBLE SOMEWHERE IN THE SRN PLAINS THURSDAY BUT
   PREDICTABILITY IS LOW DUE TO DIFFERENCES IN THE SOLUTIONS ESPECIALLY
   REGARDING LOW-LEVEL MOISTURE. ON FRIDAY/DAY 7...BOTH MODELS MOVE A
   MID-LEVEL JET OUT OVER THE SRN PLAINS WITH AN ASSOCIATED SHORTWAVE
   TROUGH IN THE SRN HIGH PLAINS. THIS PATTERN WOULD SUPPORT SEVERE
   THUNDERSTORM DEVELOPMENT ACROSS PARTS OF THE SRN AND CNTRL PLAINS
   EXTENDING EWD INTO THE LOWER MS VALLEY. AN ENHANCED SEVERE THREAT
   WILL BE POSSIBLE ON EITHER THURSDAY/DAY 6 OR FRIDAY/DAY 7 BUT
   PREDICTABILITY ON EXACTLY WHERE REMAINS LOW ATTM.

   ..BROYLES.. 04/18/2015

   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, 2015
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