923
ACUS03 KWNS 280459
SWODY3
SPC AC 280458
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1058 PM CST FRI NOV 27 2009
VALID 301200Z - 011200Z
..SYNOPSIS
SPLIT-FLOW PATTERN ALOFT FCST TO CONTINUE THROUGH DAY-3...WHILE
TRANSLATING GENERALLY ESEWD ACROSS CONUS AND ADJACENT PORTIONS NRN
MEX. STG SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL
IMAGERY OVER CENTRAL CA -- IS DEVELOPING CLOSED/EMBEDDED MID-UPPER
CYCLONE THAT WILL PERSIST THROUGH THIS PERIOD. THIS LOW SHOULD LIE
INVOF AZ/SONORA BORDER AT 30/12Z. THEREAFTER...PROGS OF 500 MB LOW
PATH BEGIN TO FAN OUT CONSIDERABLY...WITH ASSORTED SOLUTIONS FROM
CENTRAL CHIHUAHUA TO WRN NM BY END OF PERIOD. SREF CONSENSUS WOULD
PLACE THIS FEATURE OVER N-CENTRAL CHIHUAHUA...GENERALLY W OF BIG
BEND AND S OF ELP...ALTHOUGH CONFIDENCE IN THIS SCENARIO IS SHAKY
GIVEN GREAT SPREAD IN GUIDANCE TRACKS.
MEANWHILE...PHASING OF NRN STREAM PERTURBATIONS SHOULD RESULT IN
POSITIVELY-TILTED TROUGH FROM UPPER GREAT LAKES TO OK AT
30/12Z...REACHING QUE..MID-ATLANTIC STATES AND CAROLINAS BY 1/12Z.
OPERATIONAL/SREF CONSENSUS IS MUCH STRONGER FOR THIS SCENARIO THAN
FOR CLOSED SWRN LOW. RELATED SFC COLD FRONT SHOULD EXTEND FROM
MID-ATLANTIC SWD ACROSS SRN APPALACHIANS...LA AND DEEP S TX BY START
OF PERIOD. FRONT THEN SHOULD PROCEED SSEWD OFFSHORE GULF COAST FROM
TX TO FL PANHANDLE...AND ACROSS PORTIONS NRN FL BY 1/12Z.
..GULF COASTAL STATES
BAND OF PRECIP -- PERHAPS INCLUDING EMBEDDED TSTMS -- MAY BE ONGOING
INVOF FRONTAL ZONE AT START OF PERIOD...AND SHOULD AFFECT PORTIONS
GA/MS/AL...SRN LA AND DEEP S TX IN STEP WITH FRONTAL MOTION. STG
MID-UPPER FLOW IS FCST ABOVE...BUT ALSO PARALLEL TO...FRONTAL ZONE.
IN ADDITION...SFC WINDS AHEAD OF FRONT SHOULD CARRY STG WLY
COMPONENT...LIMITING BOTH SFC CONVERGENCE AND LOW-LEVEL SHEAR. SVR
POTENTIAL APPEARS TOO WEAK/CONDITIONAL FOR EVEN MRGL PROBABILITIES
ATTM...GIVEN THOSE FACTORS...AS WELL AS LIKELIHOOD OF RESTRICTED
DIABATIC HEATING UNDER CONSIDERABLE CLOUD/PRECIP COVER...AND
IMMATURITY OF RETURN-FLOW MODIFICATION IN TRAJECTORIES RETURNING
FROM GULF.
..EDWARDS.. 11/28/2009
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