|Day 4-8 Severe Weather Outlook Issued on Apr 20, 2011|
|Updated: Wed Apr 20 15:02:57 UTC 2011|
|D4||Sat, Apr 23, 2011 - Sun, Apr 24, 2011
||D7||Tue, Apr 26, 2011 - Wed, Apr 27, 2011
|D5||Sun, Apr 24, 2011 - Mon, Apr 25, 2011
||D8||Wed, Apr 27, 2011 - Thu, Apr 28, 2011
|D6||Mon, Apr 25, 2011 - Tue, Apr 26, 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).
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 200845
SPC AC 200845
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0345 AM CDT WED APR 20 2011
VALID 231200Z - 281200Z
AMPLIFICATION OF THE LARGE SCALE PATTERN IS PROBABLE BY THIS
WEEKEND/EARLY NEXT WEEK VIA A WESTERN STATES TROUGH AS PER 00Z
ECMWF/GEFS/UKMET GUIDANCE. WHILE PERIODIC BOUTS OF SEVERE WEATHER
WILL UNDOUBTEDLY OCCUR DURING THE PERIOD...CONFIDENCE IN THE
DELINEATION OF SPECIFIC 30 PERCENT CALIBER SEVERE RISK AREAS IS
LIMITED OWING TO UNCERTAINTY REGARDING SHORTWAVE-TYPE FEATURES AS
RELATED TO THE MOIST SECTOR.
ON DAYS 4-5 SATURDAY/SUNDAY...THE SOUTHERN PLAINS WILL BE A FOCUS
FOR AT LEAST SOME SURFACE BASED SEVERE THREAT NEAR/EAST OF A DRYLINE
ACROSS WEST TX AND PERHAPS INTO OK. OTHER SEVERE TSTMS MAY BE
POSSIBLE ALONG AND NORTH /IN AN ELEVATED SENSE/ OF THE FRONTAL
BOUNDARY EXTENDING NORTHEASTWARD FROM THE SOUTHERN PLAINS INTO THE
MIDDLE MS RIVER VALLEY. IN ADDITION TO A DEGREE OF MEDIUM RANGE
NUMERICAL GUIDANCE VARIABILITY...A PARTICULARLY
WIDESPREAD/APPRECIABLE SEVERE RISK IS NOT CURRENTLY ANTICIPATED.
WITH LIKELY AMPLIFICATION OF THE LARGE SCALE PATTERN VIA THE
EVOLUTION OF A PROMINENT WESTERN/CENTRAL CONUS UPPER TROUGH BY DAYS
5-6 SUNDAY/MONDAY...PRELIMINARY THINKING IS THAT A MORE
WIDESPREAD/MULTI-ROUND SEVERE THREAT MAY EVOLVE THROUGH DAYS 6-8
MONDAY/TUESDAY/WEDNESDAY FROM THE SOUTHERN PLAINS EAST-NORTHEASTWARD
INTO THE MIDWEST/MS RIVER VALLEY. BUT...SPECIFIC PREDICTABILITY IS
STILL QUITE LIMITED IN THIS TIME FRAME.
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