DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 280859
SWOD48
SPC AC 280859

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CDT THU MAR 28 2013

VALID 311200Z - 051200Z

...DISCUSSION...
SYNOPTIC ERN U.S. UPPER TROUGH IS EXPECTED TO REMAIN THE PROMINENT
FEATURE INTO MUCH OF THE 4-8 PERIOD. HOWEVER...BY DAY 5 SIGNIFICANT
MODEL DIFFERENCES ARISE REGARDING HOW THE UPPER LOW NOW OVER THE ERN
PACIFIC EVOLVES AS IT BEGINS TO INTERACT WITH ERN U.S. TROUGH. THE
ECMWF AND SOME ENSEMBLE MEMBERS RAPIDLY DEAMPLIFY AND SHEAR THIS
FEATURE EWD THROUGH THE GREAT BASIN AND CNTRL ROCKIES AS IT ENTERS
THE CONFLUENT FLOW REGIME ALONG THE SWRN PERIPHERY OF THE ERN U.S.
UPPER LOW. HOWEVER...THE GFS AND OTHER ENSEMBLE MEMBERS MAINTAIN A
MORE AMPLIFIED TROUGH AS IT CONTINUES THROUGH THE SRN ROCKIES AND
EVENTUALLY SRN PLAINS.

DAY 4 /SUNDAY/...SWRN EXTENSION OF FRONT WILL STALL OVER THE SRN
PLAINS...WHILE A MUCH STRONGER FRONT ADVANCES SWD THROUGH THE NRN
AND CNTRL PLAINS. THE WARM SECTOR SOUTH OF THE STATIONARY FRONT WILL
BECOME MODERATELY UNSTABLE WHERE STORMS MAY BE ONGOING ACROSS PARTS
OF OK AND NRN TX EARLY IN THE PERIOD. SOME OF THIS ACTIVITY MAY
DEVELOP SWD THROUGH THE TX WARM SECTOR AND INTO A PORTION OF THE
LOWER MS VALLEY UNDER THE INFLUENCE OF NWLY FLOW ALOFT. EFFECTIVE
SHEAR WILL BE SUFFICIENT FOR STORMS TO ORGANIZE WITH A THREAT OF
ISOLATED DAMAGING WIND AND LARGE HAIL. CONFIDENCE IN 30% OR GREATER
COVERAGE IS NOT HIGH ENOUGH AT THIS TIME TO DELINEATE AN AREA.
HOWEVER...PORTIONS OF TX INTO THE LOWER MS VALLEY MAY NEED TO BE
INCLUDED IN SLIGHT RISK IN LATER OUTLOOKS.

DAY 5 /MONDAY/...MODEL CONSENSUS IS THAT THE STRONG COLD FRONT WILL
CONTINUE SWD THROUGH REMAINDER OF TX AND SERN STATES. A FEW STRONG
TO SEVERE STORMS MAY DEVELOP ALONG THE FRONT...BUT CONFIDENCE IN A
30% OR GREATER COVERAGE AREA IS NOT HIGH AT THIS TIME.

DAY 6-8...MODEL SOLUTIONS BECOME INCREASINGLY DISPERSIVE WITH UPPER
PATTERN...BUT CONVECTIVE POTENTIAL WILL BE LOW IN WAKE OF THE FRONT
OVER ALL AREAS EXCEPT FL.

..DIAL.. 03/28/2013

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