[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE DEC 15 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N9W 6N17W 6N32W 1N51W. ISOLATED
MODERATE CONVECTION IS WITHIN 60 NM N OF THE AXIS BETWEEN
24W-28W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A SQUALL LINE EXTENDS FROM S CENTRAL GEORGIA
CLIPPING THE FLORIDA PANHANDLE TO THE CENTRAL LOUISIANA
COASTLINE. RADAR IMAGERY INDICATES STRONG SHOWERS/POSSIBLE
THUNDERSTORMS AFFECTING THE N CENTRAL GULF COAST...AND IMMEDIATE
COASTAL WATERS N OF 29N. FLASH FLOOD WATCHES AND WARNINGS ARE
ALREADY IN AFFECT FOR PORTIONS OF THE FLORIDA
PANHANDLE...ALABAMA...MISSISSIPPI...AND LOUISIANA. A DYING
STATIONARY FRONT EXTENDS DOWN THE TEXAS COASTLINE WITH ISOLATED
SHOWERS POSSIBLE WITHIN 90 NM OF THE COASTLINE. MAINLY SWLY FLOW
ALOFT COVERS THE BASIN. BESIDES THE MOISTURE ALONG THE FAR NRN
GULF...THE REMAINDER OF THE AREA IS COVERED BY DRY AIR ALOFT
EVIDENT ON WATER VAPOR IMAGERY SUPPORTING GENERALLY FAIR WEATHER
AND WEAK SURFACE RIDGING ACROSS THE BASIN. SE RETURN FLOW IS
OVER MUCH OF THE GULF AROUND THE WEAK SURFACE RIDGE AND AHEAD OF
THE NEXT COLD FRONT FORECAST TO MOVE OFF THE TEXAS COAST LATER
TODAY.

CARIBBEAN SEA...
STRONG ELY TRADEWINDS CONTINUE ACROSS THE CARIBBEAN AS A RESULT
OF A STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE W
ATLC AND LOW PRESSURE OVER NRN COLOMBIA. GALE FORCE WINDS TO 35
KT REMAIN NEAR THE COAST OF COLOMBIA AND ARE FORECAST TO PERSIST
THROUGH LATER TODAY. STRONG SUBSIDENCE IS ACROSS THE BASIN
AROUND AN UPPER LEVEL RIDGE CENTERED IN THE N CENTRAL CARIBBEAN
NEAR 19N75W PROVIDING GENERALLY FAIR WEATHER ACROSS THE AREA.
HOWEVER...ISOLATED LOW-LEVEL SHOWERS EMBEDDED IN THE ELY TRADES
ARE MOVING QUICKLY ACROSS PORTIONS OF THE CARIBBEAN CONCENTRATED
NEAR THE WINDWARD ISLANDS AND S OF HISPANIOLA. EXPECT LITTLE
CHANGE OVER THE NEXT 24 HRS...EXCEPT FOR WINDS NEAR THE COAST OF
COLOMBIA DIMINISHING BELOW GALE FORCE.

ATLANTIC OCEAN...
A SHORTWAVE UPPER LEVEL TROUGH N OF THE DISCUSSION AREA SUPPORTS
A COLD FRONT THAT CLIPS THE SW N ATLC ALONG 32N61W 31N70W
BECOMING STATIONARY TO THE GEORGIA COASTLINE NEAR 31N81W.
POSSIBLE ISOLATED SHOWERS ARE S OF THE FRONT FROM 27N-30N
BETWEEN 55W-67W. ELSEWHERE ACROSS THE W ATLC...A BROAD SURFACE
RIDGE DOMINATES ANCHORED BY A 1023 MB HIGH NEAR 27N63W. THE
SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE EXTENDING
FROM THE CARIBBEAN. FARTHER E...A DEEP LAYER UPPER LEVEL TROUGH
IS SUPPORTING A COLD FRONT EXTENDING FROM E OF THE AZORES
ISLANDS ENTERING THE DISCUSSION AREA NEAR 32N22W ALONG 27N25W
BECOMING A DYING FRONT NEAR 23N31W TO 21N39W. A SHEAR LINE
CONTINUES FROM THE DRYING FRONT ALONG 20N48W 18N56W 18N62W.
ISOLATED SHOWERS ARE WITHIN 60 NM OF THE FRONT AXIS...AND
POSSIBLE ALONG THE SHEAR LINE. WEAK HIGH PRESSURE IS SE OF THE
FRONT ANCHORED BY A 1016 MB HIGH NE OF THE CAPE VERDE ISLANDS
NEAR 19N20W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
WALTON






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