Friday, December 4, 2009

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 041301
SWODY1
SPC AC 041259

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0659 AM CST FRI DEC 04 2009

VALID 041300Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A SHORTWAVE TROUGH LOCATED OVER THE SRN HIGH PLAINS REMAINS ON TRACK
TO PROGRESS EWD TODAY REACHING E TX BY LATE AFTERNOON AND THE
CENTRAL/ERN GULF COAST STATES BY 12Z SATURDAY. A BOUNDARY EXTENDING
FROM ALONG THE SERN FL COAST SWWD THROUGH THE FL KEYS IS EXPECTED TO
RETREAT NWD THROUGH SRN FL THIS FORECAST PERIOD...POTENTIALLY
EXTENDING FROM NEAR MLB TO S OF TPA LATER TONIGHT.

...SRN HALF OF THE FL PENINSULA...
SEVERAL WEAK IMPULSES EMBEDDED WITHIN THE SWLY FLOW REGIME WILL
ADVANCE ENEWD THROUGH THE GULF AND CNTRL/NRN FL TODAY. THESE
FEATURES WILL SERVE TO AUGMENT LIFT AND INCREASE CONVECTIVE
POTENTIAL ALONG AND NORTH OF THE BAROCLINIC ZONE. THIS CONVECTION
IS EXPECTED TO LIMIT THE NWD RETREAT OF THE SURFACE BOUNDARY...WITH
MODELS SUGGESTING THIS SURFACE FEATURE SHOULD STRETCH FROM NEAR VRB
TO THE SWRN FL COAST BY EARLY EVENING. EFFECTIVE BULK SHEAR AND LOW
LEVEL SHEAR /NEAR THE SURFACE BOUNDARY/ WOULD BE SUFFICIENT FOR
ORGANIZED STORMS INTO THE AFTERNOON. HOWEVER...EXTENSIVE AREA OF
CLOUDS MOVING ENEWD ACROSS FAR SRN FL THIS MORNING WILL LIMIT
SURFACE HEATING AND COUPLED WITH WEAK LAPSE RATES SHOULD RESULT IN
WEAK INSTABILITY. THIS SHOULD TEND TO LIMIT THE DEVELOPMENT OF MORE
ROBUST TSTMS AND OVERALL SEVERE THREAT THROUGH THE DAY.

THE STRONGER SHORTWAVE TROUGH CURRENTLY OVER THE SRN HIGH PLAINS
WILL MOVE EAST AND INDUCE WEAK CYCLOGENESIS ALONG THE BAROCLINIC
ZONE OVER THE NRN GULF...WITH ATTENDANT INCREASE IN SWLY LOW LEVEL
JET ACROSS THE FL PENINSULA. THESE PROCESSES WILL RESULT IN NWD
RETREAT OF THE WARM FRONT TOWARD CENTRAL FL OVERNIGHT. ALTHOUGH
FORECAST SOUNDINGS SUGGEST MOST OF THE EVENING/OVERNIGHT TSTM
ACTIVITY SHOULD BE ELEVATED...AN INCREASE IN LOW LEVEL SHEAR AND
EFFECTIVE BULK SHEAR...ESPECIALLY IN VICINITY OF THE WARM
FRONT...SUPPORTS A NON-ZERO POTENTIAL FOR AN ISOLATED TORNADO.

..PETERS.. 12/04/2009

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