000
AXNT20 KNHC 151750
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

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

THE MONSOON TROUGH REACHES SOUTHERN NIGERIA 6N6E. THE ITCZ 
CONTINUES FROM 6N6E...THROUGH THE CENTER OF THE IVORY COAST...
BEYOND THE COAST OF SOUTHWESTERN SIERRA LEONE NEAR 8N13W...
8N18W 5N30W 5N36W. RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF
10N BETWEEN AFRICA AND SOUTH AMERICA.

...DISCUSSION...

THE GULF OF MEXICO...
UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA. A SURFACE 
RIDGE PASSES THROUGH THE NORTHEASTERN GULF OF MEXICO...INTO
THE CENTRAL GULF WATERS...TO THE SOUTHWESTERN CORNER OF THE
AREA. RAINSHOWERS ARE POSSIBLE FROM 23N TO 26N TO THE EAST OF 
90W...AND TO THE NORTH OF 20N BETWEEN 93W AND 96W...IN LINES
OF LOW CLOUDS AND SURFACE CONFLUENT WIND FLOW.

THE CARIBBEAN SEA...

LARGE-SCALE UPPER LEVEL ANTICYCLONIC WIND FLOW IS ASSOCIATED 
WITH A RIDGE THAT EXTENDS FROM CENTRAL VENEZUELA...THROUGH
THE SOUTH CENTRAL CARIBBEAN SEA...INTO THE NORTHWESTERN CORNER 
OF THE AREA. THE MONSOON TROUGH IS ALONG 11N73W IN THE COASTAL 
PLAINS OF NORTHERN COLOMBIA TO 10N77W...BEYOND 9N84W IN COSTA 
RICA. WIDELY SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG 
RAINSHOWERS ARE TO THE SOUTH OF 12N BETWEEN 76W AND THE COAST OF 
CENTRAL AMERICA. A SURFACE TROUGH EXTENDS FROM 23N52W IN THE 
ATLANTIC OCEAN TO 16N53W AND 13N57W...PASSING NEAR SOUTHERN 
BARBADOS...PASSING NEAR BEQUIA JUST TO THE SOUTH OF SAINT 
VINCENT...TO 13N69W. THE 24-HOUR RAINFALL TOTAL FOR THE PERIOD 
ENDING AT 15/1200 UTC FOR SAN JUAN PUERTO RICO WAS 1.04 
INCHES...AND 0.57 INCHES FOR CURACAO. A DISSIPATING COLD FRONT 
CONTINUES FROM 20N72W TO 18N80W. RAINSHOWERS ARE POSSIBLE WITHIN 
30 TO 60 NM ON EITHER SIDE OF THE FRONTAL BOUNDARY...AND TO THE 
SOUTH OF 15N60W 13N70W 12N79W.

THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH 32N56W 25N57W 15N54W.
THIS TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N49W 
24N54W TO 18N63W NEAR ANGUILLA IN THE NORTHEASTERN CARIBBEAN 
SEA. A DISSIPATING COLD FRONT CONTINUES INTO THE CARIBBEAN SEA 
ALONG 18N63W 16N68W 15N77W. A SURFACE TROUGH IS ALONG 23N52W 
16N53W 13N57W...PASSING NEAR SOUTHERN BARBADOS...PASSING NEAR 
BEQUIA JUST TO THE SOUTH OF SAINT VINCENT...TO 13N69W...IN THE 
CARIBBEAN SEA. WIDELY SCATTERED TO SCATTERED MODERATE AND 
ISOLATED STRONG RAINSHOWERS ARE FROM 12N TO 32N BETWEEN 45W AND 
53W. RAINSHOWERS ARE POSSIBLE WITHIN 30 TO 60 NM ON EITHER SIDE 
OF THE COLD FRONT...AND WITHIN 90 NM TO THE SOUTHEAST OF THE 
LINE 14N54W 12N60W. A SURFACE RIDGE PASSES THROUGH 33N24W TO 
31N30W 27N35W 24N38W 20N42W AND 13N48W. AN UPPER LEVEL TROUGH 
EXTENDS FROM THE SOUTHWESTERN COAST OF THE WESTERN SAHARA...
TO A 20N26W CYCLONIC CIRCULATION CENTER...TO 18N33W 12N36W. 
LARGE-SCALE MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND
FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 16N TO THE
EAST OF 50W.  

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

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MT