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Day 4-8 Convective Outlook Issued on Apr 17, 2011
Updated: Sun Apr 17 08:58:03 UTC 2011
Day 4-8 Convective Outlook Graphics Issued on Apr 17, 2011
D4Wed, Apr 20, 2011 - Thu, Apr 21, 2011 D7Sat, Apr 23, 2011 - Sun, Apr 24, 2011
D5Thu, Apr 21, 2011 - Fri, Apr 22, 2011 D8Sun, Apr 24, 2011 - Mon, Apr 25, 2011
D6Fri, Apr 22, 2011 - Sat, Apr 23, 2011 (All days are valid from 12 UTC - 12 UTC)

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 170858
   SPC AC 170858
   
   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0358 AM CDT SUN APR 17 2011
   
   VALID 201200Z - 251200Z
   
   ...DISCUSSION...
   PER 00Z ECMWF/GEFS/UKMET GUIDANCE...A RELATIVELY LOW AMPLITUDE/FAST
   MOVING BELT OF WEST-SOUTHWESTERLY MID/UPPER FLOW IS EXPECTED TO
   PREVAIL THROUGH THE MIDDLE/LATE PART OF THE UPCOMING WEEK. AS
   TYPICAL OF SUCH A LOW AMPLITUDE LONGWAVE REGIME...SPECIFIC
   PREDICTABILITY BEGINS TO WANE ESPECIALLY INTO DAYS 5-7. OF
   NOTE...THE 00Z GEFS/DETERMINISTIC GFS ARE MORE AMPLIFIED WITH A DAY
   5-7 WESTERN/CENTRAL CONUS UPPER TROUGH AS COMPARED TO THE 00Z
   ECMWF/UKMET...WITH UNCERTAIN RAMIFICATIONS ON THE
   LIKELIHOOD/MAGNITUDE OF SEVERE POTENTIAL IN THIS TIME FRAME.
   
   ON THE HEELS OF WHAT IS EXPECTED TO BE AN ACTIVE DAY 3/TUESDAY...AT
   LEAST SOME SEVERE THREAT MAY PERSIST INTO DAY 4/WEDNESDAY ACROSS THE
   NORTHEAST STATES ATTENDANT TO THE ADVANCING UPPER TROUGH/FAST MOVING
   COLD FRONT. LIMITED /OR AT LEAST UNCERTAIN/ DESTABILIZATION OWING TO
   THE EXTENT OF REMNANT DAY 3 CONVECTION PRECLUDES CONSIDERATION OF A
   SEVERE RISK AREA.
   
   FOR DAY 5/THURSDAY...THE SOUTH-CENTRAL PLAINS COULD BE A FOCUS FOR
   SEVERE TSTMS AS LOW LEVEL MOISTURE GRADUALLY RETURNS TOWARD A
   DEVELOPING SOUTH-CENTRAL PLAINS SURFACE LOW AND DRYLINE.
   HOWEVER...THE DEGREE OF LARGE SCALE FORCING /AMID LOW AMPLITUDE
   SOUTHWESTERLY FLOW ALOFT/ COINCIDENT WITH THE WARM/MOIST SECTOR
   CURRENTLY SEEMS QUESTIONABLE.
   
   BY DAY 6/FRIDAY...A MORE WIDESPREAD SEVERE THREAT MAY EVOLVE ACROSS
   A CORRIDOR FROM THE SOUTH-CENTRAL PLAINS TO THE MIDDLE MS RIVER
   VALLEY VICINITY...ESPECIALLY IF A MORE AMPLIFIED WESTERN STATES
   TROUGH MATERIALIZES AS PER 00Z GEFS GUIDANCE.
   
   ..GUYER.. 04/17/2011

   CLICK TO GET WUUS48 PTSD48 PRODUCT

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