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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Apr 20, 2015
Updated: Mon Apr 20 08:45:03 UTC 2015
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Thu, Apr 23, 2015 - Fri, Apr 24, 2015 D7Sun, Apr 26, 2015 - Mon, Apr 27, 2015
D5Fri, Apr 24, 2015 - Sat, Apr 25, 2015 D8Mon, Apr 27, 2015 - Tue, Apr 28, 2015
D6Sat, Apr 25, 2015 - Sun, Apr 26, 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 200843
   SPC AC 200843

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0343 AM CDT MON APR 20 2015

   VALID 231200Z - 281200Z

   ...DISCUSSION...
   THE MEDIUM-RANGE MODELS INCLUDING THE ECMWF AND GFS SOLUTIONS BEGIN
   THE 4 DAY 8 DAY PERIOD WITH AN UPPER-LEVEL RIDGE OVER THE SRN PLAINS
   EXTENDING NNWWD INTO THE CNTRL HIGH PLAINS. THE MODELS MOVE THIS
   FEATURE EWD ON THURSDAY/DAY 4 ACROSS A WARM SECTOR OVER THE ERN
   TWO-THIRDS OF TX...SRN OK AND LA. ISOLATED TO SCATTERED THUNDERSTORM
   DEVELOPMENT WILL BE POSSIBLE ACROSS THE WARM SECTOR WHERE MODERATE
   INSTABILITY AND STRONG DEEP-LAYER SHEAR SHOULD MAKE CONDITIONS
   FAVORABLE FOR SEVERE STORMS. AN ENHANCED THREAT FOR WIND DAMAGE AND
   LARGE HAIL COULD DEVELOP ACROSS THE REGION THURSDAY AFTERNOON AND
   EVENING WHERE A SLIGHT RISK HAS BEEN ADDED. MODEL SOLUTIONS DIVERGE
   SHARPLY ON FRIDAY/DAY 5 WITH THE ECMWF MOVING AN NEGATIVELY TILTED
   UPPER-LEVEL LOW INTO THE CNTRL HIGH PLAINS WHILE THE GFS MOVES A
   POSITIVELY TILTED UPPER-LEVEL TROUGH OVER THE SRN HIGH PLAINS AND
   CNTRL PLAINS. THE ECMWF SOLUTION WOULD BE FAVORABLE FOR SEVERE
   STORMS IN THE SRN AND CNTRL PLAINS WHILE THE FASTER GFS SOLUTION
   WOULD BE FAVORABLE FOR SEVERE STORMS OVER THE LOWER TO MID MS
   VALLEY. AT THIS POINT...AM LEANING TOWARD THE SLOWER ECMWF SOLUTION
   WHICH WOULD MEAN A POSSIBILITY FOR AN ENHANCED SEVERE THREAT IN FROM
   NORTH TX NWD INTO SRN KS. LARGE HAIL...WIND DAMAGE AND TORNADOES
   WOULD BE POSSIBLE FRIDAY AFTERNOON AND EVENING IN THE SRN PLAINS.
   THE POTENTIAL EXISTS FOR AN OUTBREAK OF SEVERE STORMS IF THE ECMWF
   SOLUTION VERIFIES. AT THIS POINT...THE LARGE SPREAD IN MODEL
   SOLUTIONS IS TOO GREAT TO ADD AN ENHANCED SEVERE THREAT FOR FRIDAY.
   ON SATURDAY/DAY 6...THE MODELS MOVE THE SYSTEM QUICKLY EWD ACROSS
   THE MS VALLEY WITH A ZONAL FLOW PATTERN DEVELOPING IN THE GULF COAST
   STATES. THIS PATTERN WOULD MAKE THUNDERSTORM DEVELOPMENT POSSIBLE IN
   THE GULF COAST STATES WITH A SEVERE THREAT POSSIBLE THERE DURING THE
   AFTERNOON. EVEN SO...PREDICTABILITY REMAINS QUITE LOW LATE IN THE
   DAY 4 TO 8 PERIOD.

   ..BROYLES.. 04/20/2015

   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 20, 2015
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