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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Apr 21, 2015
Updated: Tue Apr 21 08:45:02 UTC 2015
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Fri, Apr 24, 2015 - Sat, Apr 25, 2015 D7Mon, Apr 27, 2015 - Tue, Apr 28, 2015
D5Sat, Apr 25, 2015 - Sun, Apr 26, 2015 D8Tue, Apr 28, 2015 - Wed, Apr 29, 2015
D6Sun, Apr 26, 2015 - Mon, Apr 27, 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 210843
   SPC AC 210843

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0343 AM CDT TUE APR 21 2015

   VALID 241200Z - 291200Z

   ...DISCUSSION...
   THE MEDIUM-RANGE MODELS INCLUDING THE ECMWF AND GFS SOLUTIONS BEGIN
   THE DAY 4 TO 8 PERIOD WITH AN UPPER-LEVEL TROUGH OVER THE SRN
   ROCKIES EXTENDING SWD INTO NRN MEXICO AND MOVE THIS FEATURE INTO THE
   SRN PLAINS ON FRIDAY/DAY 4. BOTH SOLUTIONS MOVE A MID-LEVEL JET OVER
   A WARM SECTOR EXTENDING FROM THE ERN THIRD OF TX EWD INTO THE CNTRL
   GULF COAST STATES. SEVERE THUNDERSTORM DEVELOPMENT WITH LARGE
   HAIL...WIND DAMAGE AND POSSIBLY TORNADOES...WILL BE POSSIBLE ALONG
   AND TO THE EAST OF A DRYLINE FROM NCNTRL TX NWD INTO CNTRL OK BUT
   THE TIMING OF INITIATION IS UNCERTAIN. MORNING STORMS COULD AFFECT
   WHERE THE MOST FAVORABLE AREAS FOR SEVERE STORMS SET UP. IN
   ADDITION...SEVERE STORMS WITH LARGE HAIL AND DAMAGING WIND GUSTS
   WILL ALSO BE POSSIBLE ACROSS PARTS OF THE LOWER MS VALLEY WHERE BOTH
   SOLUTIONS DEVELOP CONVECTION ALONG THE SRN EDGE OF THE MID-LEVEL
   JET. ON SATURDAY/DAY 5...BOTH SOLUTIONS MOVE THE SHORTWAVE TROUGH
   QUICKLY EWD TO THE ATLANTIC SEABOARD AND KEEP A WARM SECTOR ACROSS
   THE GULF COAST. THIS WOULD MAKE THUNDERSTORM DEVELOPMENT WITH SOME
   POSSIBLY SEVERE...POSSIBLE SATURDAY AFTERNOON FROM SRN MS EWD INTO
   GA. ON SUNDAY/DAY 6...BOTH SOLUTIONS BRING LOW-LEVEL MOISTURE NWD
   INTO THE SRN PLAINS BUT DIFFER LONGITUDINALLY ON WHERE THE
   INSTABILITY AXIS WILL BE. THE ECMWF AND GFS ALSO DIFFER ON THE
   AMPLITUDE OF AN UPPER-LEVEL TROUGH OVER THE HIGH PLAINS. THIS ADDS
   UNCERTAINTY INTO THE FORECAST. SEVERE STORMS WILL BE POSSIBLE
   SOMEWHERE IN THE SRN PLAINS SUNDAY AFTERNOON AND EVENING DEPENDING
   UPON WHERE THE INSTABILITY AXIS SETS UP. BEYOND DAY 6...CONFIDENCE
   IS QUITE LOW CONCERNING THE MODEL SOLUTIONS.

   ..BROYLES.. 04/21/2015

   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 21, 2015
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