|Day 4-8 Severe Weather Outlook Issued on Apr 8, 2012|
|Updated: Sun Apr 8 09:00:03 UTC 2012|
|D4||Wed, Apr 11, 2012 - Thu, Apr 12, 2012
||D7||Sat, Apr 14, 2012 - Sun, Apr 15, 2012
|D5||Thu, Apr 12, 2012 - Fri, Apr 13, 2012
||D8||Sun, Apr 15, 2012 - Mon, Apr 16, 2012
|D6||Fri, Apr 13, 2012 - Sat, Apr 14, 2012
||(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 080859
SPC AC 080859
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CDT SUN APR 08 2012
VALID 111200Z - 161200Z
ALTHOUGH MEDIUM RANGE MODELS /00Z ECMWF AND GFS/ DIFFER IN THE TRACK
OF A TROUGH INTO THE CENTRAL U.S. ON D5/THU AND TO SOME DEGREE ON
D7/SAT...THESE MODELS DO AGREE IN A PATTERN CHANGE ACROSS THE CONUS
FROM MID WEEK TO NEXT WEEKEND. A BLOCKING PATTERN WITH A NWLY FLOW
REGIME OVER THE CENTRAL TO SERN U.S. WILL PERSIST INTO D4/WED WITH A
THREAT FOR SEVERE STORMS ACROSS THE SRN AND CENTRAL HIGH PLAINS.
THE PATTERN CHANGE BEGINS ON D5 AS SWLY FLOW DEVELOPS INTO THE
PLAINS DOWNSTREAM OF A LONGWAVE TROUGH EVOLVING OVER THE WRN STATES
THROUGH THE REST OF THE EXTENDED PERIOD.
FOR D5/THU...THE GFS AND ECMWF CONTINUE TO DIFFER WITH THE TRACK OF
THE SHORTWAVE TROUGH FROM LATE D4/WED THROUGH D5. ALTHOUGH THE GFS
IS MAINTAINING A NRN TRACK BIAS WITH WEAKER FORCING ACROSS
KS/OK...THE WARM SECTORS IN EACH MODEL ARE SIMILAR. NORMALLY THESE
TYPES OF MODEL VARIANCES IN THE MID-UPPER LEVELS WOULD RESULT IN NOT
INCLUDING A REGIONAL SEVERE WEATHER THREAT AREA. HOWEVER...GFS
FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SUPERCELLS ALONG THE
DRY LINE...BUT WITH LOWER COVERAGE. THIS FACTOR COMBINED WITH THE
FORECAST FOR STRONGER WIND FIELDS PER THE ECMWF SUGGESTS THE
REGIONAL SEVERE WEATHER THREAT AREA WILL BE MAINTAINED INTO D5 WITH
THE POTENTIAL FOR LARGE HAIL AND TORNADOES.
THE MODEL DIFFERENCES WITH THE TRACK OF THE D5/THU TROUGH AFFECT THE
SEVERE WEATHER FORECAST FOR D6/FRI...WITH THE GFS FAVORING A MORE
NRN TRACK ACROSS KS/NEB INTO IA...WHILE THE ECMWF INDICATED A
GREATER THREAT FARTHER TO THE SSE.
FOR D7/SAT...THE GFS/ECMWF ARE IN BETTER AGREEMENT AGAIN WITH
RESPECT TO THE DISTRIBUTION OF LOW LEVEL MOISTURE AND WARM SECTOR
SETUP ACROSS TX INTO KS. GREATEST JUXTAPOSITION OF INSTABILITY AND
STRONG DEEP LAYER SHEAR SUPPORTS ANOTHER REGIONAL SEVERE WEATHER
THREAT AREA SIMILAR TO D5 ACROSS OK/KS.
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