[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112322
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN DEC 11 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC NEAR 14N17W TO 10N19W. THE ITCZ CONTINUES FROM 10N19W ALONG
7N26W 5N38W TO 1N47W. NO SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS OVER THE E CONUS WITH A SHORTWAVE UPPER
TROUGH OVER THE LOWER MISSISSIPPI VALLEY USHERING MID/UPPER
LEVEL MOISTURE OVER MISSISSIPPI TO GEORGIA AND SOUTH CAROLINA
WITH SCATTERED TO HEAVY RAINS ACROSS THE S PORTIONS OF
MISSISSIPPI...ALABAMA...GEORGIA...AND THE FLORIDA PANHANDLE WITH
SCATTERED SHOWERS IN THE NE GULF MAINLY N OF 27N E OF 88W. THE
REMAINDER OF THE GULF UPPER LEVELS ARE NEAR ZONAL WESTERLY
FLOW. STRONG SURFACE RIDGE DOMINATES THE GULF AND ANCHORED BY A
1038 MB HIGH OVER NEW ENGLAND. EASTERLY SURFACE FLOW COUPLED
WITH LOW LEVEL MOISTURE IS GIVING THE REMAINDER OF THE GULF
MOSTLY CLOUDY SKIES WITH PATCHES OF SCATTERED SHOWERS. SURFACE
RIDGE  WILL SHIFT BEGIN TO SHIFT E ON WED THROUGH FRI ALLOWING
RETURN FLOW OVER THE W GULF TO SPREAD EASTWARD. THE NEXT COLD
FRONT WILL STALL OVER THE TEXAS COAST THU NIGHT AND DRIFT WELL W
OF AREA ON FRI.

CARIBBEAN SEA...
WEAK PRESSURE PATTERN DOMINATES THE CARIBBEAN THIS EVENING. A
BROAD UPPER RIDGE AXIS EXTENDS FROM SOUTH AMERICA OVER COLOMBIA
NEAR 11N73W NW TO W CUBA NEAR THE ISLE OF YOUTH GIVING THE E
CARIBBEAN MOSTLY WESTERLY FLOW ALOFT. THIS UPPER RIDGE IS
DRAWING TROPICAL MOISTURE N OVER THE S/CENTRAL CARIBBEAN AND
COUPLED WITH THE MONSOON TROUGH THAT EXTENDS FROM COLOMBIA NEAR
11N74W ACROSS PANAMA/COSTA RICA NEAR 9N83W INTO THE E PACIFIC
REGION ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S
OF 15N BETWEEN 75W-84W. THE REMAINDER OF THE CARIBBEAN IS UNDER
MOSTLY FAIR CONDITIONS THIS EVENING WITH THE POSSIBLE ISOLATED
LOW LEVEL SHOWER USHERED IN ON THE EASTERLY TRADE WINDS. THE
RIDGE OVER THE W ATLC WILL TIGHTEN THE PRESSURE GRADIENT LATER
IN THE WEEK INCREASING TRADE WINDS.

ATLANTIC OCEAN...
THE BROAD UPPER TROUGH OVER THE E CONUS EXTENDS INTO THE NW ATLC
SUPPORTING A WEAKENING COLD FRONT THAT ENTERS THE W ATLC AT
12/2100 UTC NEAR 32N67W TO 29N76W. THE BROAD UPPER RIDGE OVER
THE CARIBBEAN COVERS THE REMAINDER OF THE W ATLC WITH STRONG
SUBSIDENCE AND DRY STABLE AIR SE OF THE ABOVE FRONT W OF
60W...THIS LIMITING SHOWER ACTIVITY OVER THE AREA. A BROAD
ELONGATED UPPER LOW IS OVER THE CENTRAL ATLC EXTENDING FROM
28N60W THROUGH 23N56W TO 20N50W SUPPORTING A SURFACE TROUGH
ANALYZED FROM 27N62W TO 20N61W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 175/200 NM OF LINE FROM 18N48W TO
27N58W. BROAD UPPER RIDGE RIDGE IS ANCHORED N OF THE DISCUSSION
AREA NEAR 33N41W COVERING THE REMAINDER OF THE CENTRAL AND THE E
ATLC WITH A SURFACE RIDGE COVERING THE E ATLC ANCHORED BY A 1032
MB HIGH N OF THE DISCUSSION AREA ABOUT 400 NM SW OF THE AZORES.
THE W ATLC SURFACE RIDGE WILL BUILD E BY TUE AS A NEW COLD FRONT
FORMS ALONG 65W THEN THE FRONT WILL SHIFT INTO THE CENTRAL ATLC
THROUGH FRI STRENGTHENING THE RIDGE OVER THE W ATLC.

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

$$
PAW





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