|Day 4-8 Severe Weather Outlook Issued on Apr 21, 2011|
|Updated: Thu Apr 21 22:13:20 UTC 2011|
|D4||Sun, Apr 24, 2011 - Mon, Apr 25, 2011
||D7||Wed, Apr 27, 2011 - Thu, Apr 28, 2011
|D5||Mon, Apr 25, 2011 - Tue, Apr 26, 2011
||D8||Thu, Apr 28, 2011 - Fri, Apr 29, 2011
|D6||Tue, Apr 26, 2011 - Wed, Apr 27, 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 210859
SPC AC 210859
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CDT THU APR 21 2011
VALID 241200Z - 291200Z
WHILE SOME DETAILS VARY...THE 00Z ECMWF/GEFS/UKMET ARE IN AMPLE
GENERAL AGREEMENT WITH THE EXPECTED AMPLIFICATION OF THE LARGE SCALE
PATTERN LATE THIS WEEKEND/EARLY NEXT WEEK...HIGHLIGHTED BY A
PROMINENT WESTERN/CENTRAL CONUS UPPER TROUGH.
ON DAY 4/SUNDAY...THE SOUTHERN HIGH PLAINS WILL LIKELY BE A FOCUS
FOR AT LEAST SOME SURFACE BASED SEVERE THREAT NEAR/EAST OF A DRYLINE
ACROSS WEST TX AND PERHAPS INTO OK. OTHER ELEVATED STORMS CAPABLE OF
SEVERE HAIL ARE PROBABLE SUNDAY NIGHT FROM OK INTO THE OZARKS/LOWER
MO VALLEY. BUT GIVEN LINGERING UNCERTAINTY REGARDING THE EXTENT OF
PRE-DARK SURFACE BASED DEEP CONVECTION...LARGELY OWING TO
ANTICIPATED MODEST LARGE SCALE FORCING FOR ASCENT/ONLY WEAK HEIGHT
FALLS...TOO MUCH UNCERTAINTY CURRENTLY EXISTS TO DELINEATE A 30
PERCENT EQUIVALENT SEVERE RISK AREA.
FOR DAY 5/MONDAY...HAVE INTRODUCED A SEVERE RISK AREA FOR PORTIONS
OF THE SOUTHERN PLAINS TO THE ARKLATEX/OZARKS. WHILE TIMING/SPATIAL
DETAILS VARY TO A DEGREE...REASONABLE CONFIDENCE EXISTS THAT A
SOUTHERN STREAM SHORTWAVE TROUGH WILL OVERSPREAD A MOIST AIRMASS TO
THE EAST OF THE DRYLINE/COLD FRONT. AS SUCH...SEVERE STORMS SEEM
LIKELY MONDAY/MONDAY NIGHT ACROSS THIS REGION.
INTO DAYS 6/7 TUESDAY/WEDNESDAY...AS THE NEXT PORTION OF THE CENTRAL
CONUS UPPER TROUGH PIVOTS EASTWARD...A RELATIVELY
WIDESPREAD/MULTI-ROUND SEVERE THREAT IS EXPECTED FROM THE SOUTHERN
PLAINS EAST-NORTHEASTWARD INTO THE MIDWEST AND LOWER/MIDDLE MS RIVER
VALLEY. WHILE SEVERE STORMS SEEM LIKELY EACH OF THESE
DAYS...SPECIFIC PREDICTABILITY IS STILL QUITE LIMITED IN THIS TIME
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