Friday, October 29, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 290517
SWODY1
SPC AC 290516

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 AM CDT FRI OCT 29 2010

VALID 291200Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MODELS INDICATE THAT A SPLIT FLOW WILL PERSIST ACROSS THE EASTERN
PACIFIC AND WESTERN NORTH AMERICA...DOWNSTREAM OF ANOTHER STRONG
ZONAL UPPER JET NOSING ACROSS THE MID LATITUDE PACIFIC. WHILE A
MID/UPPER RIDGE BUILDS WITHIN THE NORTHERN BRANCH EAST OF THE
CANADIAN ROCKIES...A CLOSED LOW WITHIN THE SOUTHERN BRANCH IS
PROGGED TO MIGRATE INLAND ACROSS THE CALIFORNIA COAST BY THE END OF
THE FORECAST PERIOD. FARTHER DOWNSTREAM...BROAD SOUTHERN STREAM
RIDGING APPEARS LIKELY TO PERSIST ACROSS MUCH OF THE PLAINS AND
MISSISSIPPI VALLEY...BUT A SIGNIFICANT SHORT WAVE IMPULSE IS PROGGED
TO ACCELERATE EAST NORTHEAST OF THE MID ATLANTIC COAST... AS AN
ELONGATING CIRCULATION WITHIN THE NORTHERN BRANCH MIGRATES EAST
SOUTHEASTWARD ACROSS ONTARIO/QUEBEC AND PARTS OF NEW ENGLAND.

IN RESPONSE TO THE LEAD IMPULSE...A COLD FRONT IS EXPECTED TO
CONTINUE TO PROGRESS AWAY FROM ATLANTIC COASTAL AREAS...AND
SOUTHWARD THROUGH THE REMAINDER OF THE FLORIDA PENINSULA...WITH A
LARGE SURFACE RIDGE BECOMING CENTERED OVER MUCH OF THE GULF COAST
AND SOUTHEASTERN STATES. DRY...STABLE CONDITIONS ARE EXPECTED TO BE
MAINTAINED OVER MUCH OF THE NATION...WITH LOW TO NEGLIGIBLE
POTENTIAL FOR THUNDERSTORM ACTIVITY.

...FLORIDA...
THUNDERSTORM ACTIVITY MAY PERSIST IN OR NEAR EAST CENTRAL FLORIDA
COAST ATLANTIC COASTAL WATERS...BEFORE THE SURFACE FRONTAL PASSAGE
STABILIZES THE ENVIRONMENT BY THE MID MORNING HOURS.
THEREAFTER...AS THE FRONT ADVANCES SOUTHWARD...MODELS SUGGEST
LOW-LEVEL CONVERGENCE WILL BECOME FOCUSED ACROSS THE INTERIOR
SOUTHERN PENINSULA BY 18-21Z...WHEN HEATING OF A MOIST BOUNDARY
LAYER MAY YIELD MODERATELY LARGE CAPE...AND CONTRIBUTE TO WEAKENING
INHIBITION. A FEW THUNDERSTORMS APPEAR POSSIBLE...WITH DIFLUENT
UPPER FLOW PERHAPS SUPPORTING THE EVOLUTION OF A SMALL STORM
CLUSTER. IF THIS OCCURS...LIGHT NORTHERLY FLOW MAY AID SOUTHWARD
PROPAGATION ACROSS PORTIONS OF THE KEYS BY EARLY EVENING.

...CALIFORNIA...
CONSIDERABLE VARIABILITY EXISTS AMONG THE MODELS CONCERNING THE
TIMING OF THE INLAND PROGRESSION OF THE CLOSED LOW. HOWEVER... THE
MID-LEVEL COLD CORE DOES NOT APPEAR LIKELY TO PROGRESS ONSHORE UNTIL
THE EVENING HOURS AT THE EARLIEST. STILL...IT DOES NOT SEEM OUT OF
THE QUESTION THAT SUFFICIENT DESTABILIZATION COULD OCCUR TO SUPPORT
AT LEAST 10 PERCENT THUNDERSTORM PROBABILITIES...PARTICULARLY ACROSS
THE COASTAL RANGES BETWEEN SAN FRANCISCO BAY AND THE LOS ANGELES
BASIN.

..KERR.. 10/29/2010

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