Skip Navigation Links weather.gov 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap


 
USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

Day 4-8 Severe Weather Outlook Issued on May 26, 2013
Updated: Sun May 26 09:01:03 UTC 2013
Day 4-8 Severe Weather Outlook Graphics Issued on May 26, 2013
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
D4 35,609 75,398 Pierre, SD...Rosebud, SD...Lemmon, SD...Kyle, SD...Dupree, SD...
D4Wed, May 29, 2013 - Thu, May 30, 2013 D7Sat, Jun 01, 2013 - Sun, Jun 02, 2013
D5Thu, May 30, 2013 - Fri, May 31, 2013 D8Sun, Jun 02, 2013 - Mon, Jun 03, 2013
D6Fri, May 31, 2013 - Sat, Jun 01, 2013 (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 260859
   SPC AC 260859

   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0359 AM CDT SUN MAY 26 2013

   VALID 291200Z - 031200Z

   ...DISCUSSION...
   MODELS ARE IN FAIR AGREEMENT DURING THE EARLY PORTION OF THE
   EXTENDED PERIOD IN SHOWING A HIGH AMPLITUDE NEGATIVELY-TILTED UPPER
   TROUGH EJECTING INTO THE PLAINS WHILE A MID LEVEL ANTICYCLONE
   REMAINS SITUATED NEAR THE NC OUTER BANKS.  THE WRN U.S. SYSTEM WILL
   LIKELY EVOLVE INTO A CLOSED MID LEVEL LOW OVER THE NRN ROCKIES/NRN
   HIGH PLAINS BY LATE IN THE WORK WEEK. 

   ON WEDNESDAY /DAY 4/...A MERIDIONAL FLOW REGIME OVER THE PLAINS WILL
   FAVOR SCTD TO NUMEROUS SHOWERS/STORMS AS STRONG UPPER FORCING FOR
   ASCENT/STRONG SHEAR WILL SUPPORT ISOLD SEVERE STORMS POTENTIALLY
   OVER A LARGE PORTION OF THE PLAINS/UPPER MIDWEST.  IT APPEARS THE
   MOST PROBABLE CONCENTRATION FOR SEVERE --INCLUDING POSSIBLE TORNADIC
   STORMS-- WILL BE IN THE ERN PART OF THE HIGH PLAINS.  AT THIS
   TIME...CONFIDENCE IS HIGHEST FOR THIS SCENARIO OVER PARTS OF THE WRN
   DAKOTAS/NEB...BUT AN EVENTUAL EXTENSION IN 30 PERCENT SEVERE
   PROBABILITIES MAY BE WARRANTED IN LATER OUTLOOKS FOR AREAS FARTHER S
   IN THE SRN HIGH PLAINS.  

   BY THURSDAY /DAY 5/...DESPITE STRENGTHENING SHEAR PROFILES FAVORABLE
   FOR ORGANIZED SEVERE STORMS CAPABLE OF ALL FACETS OF SEVERE
   --FARTHER E IN A CORRIDOR FROM THE SRN PLAINS NWD INTO THE UPPER
   MIDWEST-- PRIOR DAY/S SUBSTANTIAL CONVECTIVE OVERTURNING OF STEEP
   MID LEVEL LAPSE RATES IS AT LEAST PARTLY EXPECTED OVER THE PLAINS
   AND MAY AFFECT THE MAGNITUDE OF DESTABILIZATION DOWNSTREAM OVER THE
   UPPER MS RIVER VALLEY.  AS A RESULT...THIS FORECAST SCENARIO LENDS
   CONSIDERABLE UNCERTAINTY PRECLUDING A HIGHLIGHT AREA FOR THE TIME
   BEING OVER THE UPPER MIDWEST.  FARTHER S...MODELS HINT AT A
   REJUVENATION OF STEEP LAPSE RATES PROTRUDING E INTO THE CNTRL-SRN
   PLAINS.  COUPLED WITH STRONG FLOW FIELDS AND RICH MOISTURE...A
   HIGHER PROBABILITY AREA MAY BE NEEDED FOR PARTS OF THE CNTRL-SRN
   PLAINS IF CONFIDENCE IS MAINTAINED/INCREASES FOR LATER OUTLOOK
   UPDATES.  

   FRIDAY /DAY 6/ MAY CONTINUE TO FOSTER EPISODIC BOUTS OF ORGANIZED
   SEVERE STORMS IN A GENERAL AREA FROM THE CNTRL-SRN PLAINS NEWD INTO
   THE UPPER MS RIVER VALLEY.  AGAIN...THE INGREDIENTS FOR STORMS
   CAPABLE OF SEVERE WEATHER MAY JUXTAPOSE IN TIME/SPACE BUT THE
   COMBINATION OF UNCERTAINTY/MODEL PREDICTABILITY PRECLUDES AN AREA
   HIGHLIGHT THIS DAY AS WELL.

   ..SMITH.. 05/26/2013

   CLICK TO GET WUUS48 PTSD48 PRODUCT
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
spc.feedback@noaa.gov
Page last modified: September 21, 2020
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities