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 Dec 22, 2012
Updated: Sat Dec 22 09:59:03 UTC 2012
Day 4-8 Severe Weather Outlook Graphics Issued on Dec 22, 2012
D4Tue, Dec 25, 2012 - Wed, Dec 26, 2012 D7Fri, Dec 28, 2012 - Sat, Dec 29, 2012
D5Wed, Dec 26, 2012 - Thu, Dec 27, 2012 D8Sat, Dec 29, 2012 - Sun, Dec 30, 2012
D6Thu, Dec 27, 2012 - Fri, Dec 28, 2012 (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 220958
   SPC AC 220958
   
   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0358 AM CST SAT DEC 22 2012
   
   VALID 251200Z - 301200Z
   
   ...DISCUSSION...
   THE MEDIUM RANGE MODELS MOVE A PROGRESSIVE UPPER-LEVEL TROUGH
   QUICKLY ESEWD ACROSS THE ROCKIES MONDAY NIGHT AND INTO THE SRN
   PLAINS ON TUESDAY/DAY 4. STRONG LARGE-SCALE ASCENT AND MOISTURE
   RETURN AHEAD OF THE SYSTEM WILL ALLOW SCATTERED TO NUMEROUS
   THUNDERSTORMS TO DEVELOP ACROSS THE TX COASTAL PLAINS AND IN THE
   LOWER MS VALLEY FROM LATE MONDAY NIGHT INTO TUESDAY. AS THE EXIT
   REGION OF A POWERFUL MID-LEVEL JET NOSES INTO THE LOWER MS
   VALLEY...SEVERE STORMS WILL BE POSSIBLE DUE TO STRONG DEEP LAYER
   SHEAR AND WIDESPREAD ASCENT. THE PROGRESSIVE NATURE OF THE SYSTEM
   MAY ENABLE A SQUALL-LINE TO ORGANIZE AND QUICKLY MOVE EWD ACROSS THE
   LOWER MS VALLEY ON TUESDAY AND INTO THE CNTRL GULF COAST STATES. IT
   APPEARS THAT A SUBSTANTIAL SEVERE WEATHER THREAT WILL BE POSSIBLE ON
   TUESDAY AND TUESDAY NIGHT ACROSS A BROAD CORRIDOR FROM SE TX
   EXTENDING ENEWD ACROSS LA...MS ...AL AND INTO THE FL PANHANDLE. 
   
   AS THIS SYSTEM CONTINUES TO MOVE ENEWD INTO THE CAROLINAS ON
   WEDNESDAY/DAY 5...A SEVERE THREAT WILL CONTINUE TO BE POSSIBLE. AN
   ENHANCED SEVERE THREAT COULD OCCUR IF A LINEAR MCS OR A CLUSTER OF
   SEVERE STORMS MOVES INTO THE REGION FROM THE WEST LATE TUESDAY
   NIGHT. AT THIS POINT...WILL NOT ISSUE AN OUTLOOK AREA FOR THE
   CAROLINAS UNTIL CONFIDENCE IS A BIT GREATER CONCERNING THE TIMING OF
   THE UPPER-LEVEL TROUGH. BY LATE IN THE DAY 4 TO 8 PERIOD...THE
   MODELS MOVE ANOTHER UPPER-LEVEL TROUGH INTO THE CNTRL U.S. THIS
   COULD BE FAVORABLE FOR STRONG THUNDERSTORMS IN THE LOWER TO MID MS
   VALLEY AGAIN ON FRIDAY/DAY 7 BUT MUCH UNCERTAINTY EXISTS AT THIS
   RANGE.
   
   ..BROYLES.. 12/22/2012

   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:
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities