Saturday, December 28, 2013

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 281730
SWODY2
SPC AC 281729

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CST SAT DEC 28 2013

VALID 291200Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A LARGE UPPER TROUGH -- EVOLVING AS NRN AND SRN STREAM FEATURES
CONTINUE PHASING -- IS FORECAST TO MOVE EWD ACROSS THE CENTRAL U.S.
THIS PERIOD. AHEAD OF THE LARGER/EVOLVING TROUGH...A LEAD
SHORT-WAVE IMPULSE IS PROGGED TO MOVE QUICKLY NEWD FROM THE CENTRAL
GULF COAST/MID SOUTH REGION TO THE MID-ATLANTIC STATES DURING THE
FIRST HALF OF THE PERIOD...AND THEN ACROSS NEW ENGLAND INTO THE
CANADIAN MARITIMES OVERNIGHT.

WHILE A COLD FRONT AT THE LEADING EDGE OF A SURGE OF POLAR AIR WILL
SHIFT QUICKLY SEWD ACROSS THE CENTRAL CONUS...THE MAIN FEATURE WITH
RESPECT TO THE CONVECTIVE FORECAST WILL BE A ZONE OF CYCLOGENESIS
OVER THE SERN STATES. HERE...A LOW INITIALLY INVOF ERN GA --
ASSOCIATED WITH THE AFOREMENTIONED SHORT-WAVE UPPER TROUGH -- IS
FORECAST TO SHIFT NEWD ACROSS THE CAROLINAS TO THE MID-ATLANTIC
COAST THROUGH THE FIRST HALF OF THE PERIOD. AHEAD OF THE TRAILING
COLD FRONT...MEAGER WARM SECTOR INSTABILITY IS EXPECTED -- FUELING
AN AREA OF MAINLY WEAK CONVECTION THROUGH SUNSET.

...COASTAL CAROLINAS SWWD TO SERN GA/NERN FL...
AS THE ERN GA SURFACE LOW SHIFTS QUICKLY NEWD ACROSS THE ERN
SEABOARD WITH TIME...A RESULTING SEWD COLD FRONTAL SURGE WILL OCCUR
ACROSS SC/GA AND INTO N FL DURING THE MORNING HOURS. IN
CONJUNCTION...A FRONTAL BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS
WILL LIKEWISE MOVE QUICKLY EWD...LIKELY CLEARING THE SC/GA/NERN FL
COASTS BY NOON. WHILE ONSHORE HOWEVER...A WEAKLY UNSTABLE
WARM-SECTOR AIRMASS COMBINED WITH A VERY STRONG WIND FIELD VEERING
GRADUALLY WITH HEIGHT SUGGESTS THAT THE STRONGER CONVECTIVE ELEMENTS
WILL BE CAPABLE OF PRODUCING A LOCALLY DAMAGING GUST OR TWO -- AND
POSSIBLY A BRIEF TORNADO.

THE GREATEST RISK SHOULD EXIST NEAR AND NE OF THE SURFACE
LOW...WHERE THE MOST FAVORABLE KINEMATICS WILL EXIST -- THUS
PARTIALLY OFFSETTING THE MEAGER INSTABILITY. WHILE THE FRONT SURGES
OFFSHORE ACROSS GA AND SC...A NARROW WARM SECTOR SHOULD REMAIN
INLAND ACROSS ERN NC AND THE OUTER BANKS THROUGH ROUGHLY SUNSET --
ALLOWING SOME RISK FOR ISOLATED DAMAGING WINDS AND PERHAPS A TORNADO
OR TWO TO PERSIST IN THIS AREA THROUGH THE AFTERNOON. OVERALL
HOWEVER...THE AFOREMENTIONED MEAGER WARM-SECTOR INSTABILITY SUGGESTS
THAT SEVERE RISK WILL REMAIN ISOLATED AT BEST.

FARTHER S...MORE LOOSELY ORGANIZED/ISOLATED SHOWERS AND STORMS ARE
LIKELY TO CONTINUE AFFECTING CENTRAL AND S FL THROUGH THE
AFTERNOON...AS THE FRONT SAGS MORE SLOWLY SWD ACROSS THE PENINSULA.
HOWEVER...WITH THE COMBINATION OF VEERED LOW-LEVEL FLOW ROUGHLY
PARALLEL TO THE FRONT...AND DEEP-LAYER MAGNITUDE OF THE WINDS ALOFT
MUCH WEAKER THAN AREAS FARTHER N...SEVERE RISK SHOULD REMAIN
MINIMAL.

..GOSS.. 12/28/2013

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