Friday, January 15, 2010

DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 150946
SWOD48
SPC AC 150945

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0345 AM CST FRI JAN 15 2010

VALID 181200Z - 231200Z

...DISCUSSION...

THE ECMWF...GFS AND MREF ENSEMBLE MEMBERS ARE IN REASONABLY GOOD
AGREEMENT...PARTICULARLY WITH EVOLUTION OF SRN BRANCH OF WLYS
THROUGH AT LEAST DAY 7. VERY ACTIVE SRN STREAM IS FORECAST ACROSS
THE SRN THIRD OF THE COUNTRY AS STRONG SUBTROPICAL JET BECOMES
ESTABLISHED.

LATE DAY 5 INTO DAY 6...INITIAL SHORTWAVE TROUGH IS FORECAST TO MOVE
INTO THE SRN PLAINS TUESDAY NIGHT BEFORE DEAMPLIFYING AS IT EJECTS
THROUGH THE MS...TN AND OH VALLEYS WEDNESDAY. THIS FEATURE WILL BE
FOLLOWED CLOSELY BY AN UPSTREAM IMPULSE. AXIS OF PARTIALLY MODIFIED
GULF AIR SHOULD RETURN NWD FROM ERN TX INTO THE LOWER MS VALLEY
BENEATH STEEPENING LAPSE RATES ASSOCIATED WITH COLD AIR
ALOFT...LIKELY RESULTING IN DESTABILIZATION. STORMS WILL PROBABLY
DEVELOP WITHIN ZONE OF INCREASING ISENTROPIC LIFT AND WARM ADVECTION
ACROSS ERN TX TUESDAY NIGHT AND SHIFT EWD THROUGH THE LOWER MS
VALLEY WEDNESDAY. PRIMARY UNCERTAINTY AT THIS TIME IS DEGREE OF
SURFACE BASED INSTABILITY AND MOISTURE RETURN THAT WILL BE AVAILABLE
FOR A HIGHER END SEVERE EVENT. PREFER TO WAIT FOR AT LEAST ANOTHER
SET OF MODEL RUNS BEFORE INTRODUCING SEVERE PROBABILITIES. IF MODELS
REMAIN CONSISTENT...A SEVERE THREAT AREA MIGHT BE INTRODUCED IN THE
NEXT 4-8 OUTLOOK FROM ERN TX THROUGH PARTS OF THE LOWER MS VALLEY
AND THE GULF COASTAL REGION FOR TUESDAY INTO WEDNESDAY.

DAY 7...SEVERE THREAT MAY SHIFT INTO THE FL PENINSULA THURSDAY.
HOWEVER...CONFIDENCE IN A HIGHER END SEVERE EVENT IS NOT SUFFICIENT
TO INTRODUCE A THREAT AREA AT THIS TIME.

..DIAL.. 01/15/2010

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