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| Day 4-8 Severe Weather Outlook Issued on Apr 21, 2011 |
| Updated: Thu Apr 21 22:13:20 UTC 2011 |
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| 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) |
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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.
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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.
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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).
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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
...DISCUSSION...
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
FRAME.
..GUYER.. 04/21/2011
CLICK TO GET WUUS48 PTSD48 PRODUCT
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