000
AXNT20 KNHC 050553
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST MON DEC 05 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 
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL 
ATLC NEAR 12N15W TO 9N18W. THE ITCZ CONTINUES FROM 9N18W ALONG 
5N25W 6N40W TO SOUTH AMERICA NEAR 5N54W. SCATTERED MODERATE/ 
STRONG CONVECTION IS FROM 5N-7N BETWEEN 33W-40W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE 
REMAINDER OF THE AREA FROM 2N-8N BETWEEN 27W-45W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS OVER THE CENTRAL PLAIN STATES TO OVER MEXICO 
APPROACHING THE GULF WATERS SUPPORTING A COLD FRONT THAT 05/0300 
UTC ENTERS THE GULF FROM A 1014 MB LOW CENTERED BETWEEN THE 
LOUISIANA BORDER AND HOUSTON TEXAS CONTINUES ALONG THE COAST OF 
TEXAS INLAND NEAR CORPUS CHRISTI ACROSS S TEXAS TO OVER NE 
MEXICO. A SURFACE RIDGE DOMINATES THE REMAINDER OF THE GULF 
ANCHORED S OF NOVA SCOTIA AND A 1030 MB HIGH OVER VIRGINIA. THIS 
SURFACE RIDGE IS GIVING MOST OF THE GULF SOUTHERLY RETURN FLOW 
WITH PATCHES OF SCATTERED SHOWERS WITHIN THIS FLOW MAINLY N OF 
24N W OF 87W AHEAD OF THE ABOVE FRONT. THE REMAINDER OF THE 
UPPER LEVELS ARE DOMINATED BY AN UPPER RIDGE WITH AN AXIS 
EXTENDING FROM THE BAY OF CAMPECHE TO ACROSS NE FLORIDA COVERING 
THE W CARIBBEAN AND INTO THE W ATLC. THE COLD FRONT WILL EXTEND 
FROM SE LOUISIANA TO TAMPICO MEXICO MON NIGHT THEN FROM MOBILE 
ALABAMA TO W BAY OF CAMPECHE TUE NIGHT. FRONT WILL THEN BRIEFLY 
STALL ON WED BEFORE ADVANCING E THU MOVING OUT OF THE GULF LATE 
THU OR EARLY FRI.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COMBINED WITH AN UPPER 
TROUGH OVER THE CENTRAL CARIBBEAN IS GIVING THE W CARIBBEAN NW 
FLOW ALOFT. A NARROW UPPER TROUGH AXIS EXTENDS FROM THE CENTRAL 
ATLC ACROSS THE DOMINICAN REPUBLIC NEAR 19N70W ALONG 13N75W TO 
PANAMA NEAR 9N78W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF 
A LINE FROM E PUERTO RICO NEAR 18N66W TO PANAMA NEAR 9N78W WHILE 
MOIST TROPICAL AIR IS TO THE E OF THIS LINE. EMBEDDED WITH THE 
MOIST AREA IS A SURFACE TROUGH THAT EXTENDS FROM 15N63W THROUGH 
THE LEEWARD/VIRGIN ISLANDS NEAR 18N63W INTO THE CENTRAL ATLC. 
SCATTERED SHOWERS AND CLUSTERS OF ISOLATED THUNDERSTORMS ARE IN 
THE MOIST SECTOR OF THE CARIBBEAN WHILE THE REMAINDER OF THE 
CARIBBEAN IS UNDER FAIR CONDITIONS TONIGHT. THE LESSER ANTILLES 
HAVE BEEN RECEIVING RAIN FOR THE PAST COUPLE OF DAYS AND WITH 
THESE SHOWERS/THUNDERSTORMS TRAINING NE ACROSS THE ISLANDS HAVE 
THE POTENTIAL FOR FLOODING ESPECIALLY IN MOUNTAINOUS REGIONS. 
THESE RAINS ARE FORECASTED TO CONTINUE THROUGH MON NIGHT. 

ATLANTIC OCEAN...
AN UPPER RIDGE EXTENDS AN AXIS FROM THE GULF OF MEXICO ACROSS NE 
FLORIDA INTO THE W ATLC TO BEYOND 32N76W COVERING THE FAR W 
ATLC. A SURFACE RIDGE COVERS THE W ATLC W OF 65W INTO THE GULF 
OF MEXICO. A NARROW UPPER TROUGH IS IN THE CENTRAL ATLC 
EXTENDING FROM AN UPPER LOW NEAR 29N62W INTO THE CENTRAL 
CARIBBEAN ACROSS THE DOMINICAN REPUBLIC NEAR 19N70W SUPPORTING A 
SURFACE TROUGH THAT EXTENDS FROM 29N57W ALONG 27N61W INTO THE E 
CARIBBEAN THROUGH THE LEEWARD/VIRGIN ISLANDS NEAR 18N63W. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 26N-28N 
BETWEEN 60W-64W. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR 
COVER THE W ATLC W OF 63W GIVING THE AREA FAIR WEATHER TONIGHT. 
AN UPPER RIDGE IS TO THE E OF THE UPPER TROUGH EXTENDING FROM 
NEAR 16N55W TO BEYOND 32N50W PROVIDING DIFFLUENCE ALOFT TO 
GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 
FROM 15N-20N BETWEEN 52W-63W AND FROM 20N-30N W OF 53W TO THE 
SURFACE TROUGH. A SECOND SURFACE TROUGH EXTENDS FROM 31N46W TO 
26N42W ASSOCIATED WITH THE REMNANTS OF AN UPPER LEVEL SYSTEM 
THAT HAS BEEN ABSORBED INTO A LARGER UPPER LOW TO THE E CENTERED 
NEAR 29N31W AND COVERS THE AREA N OF 17N BETWEEN 20W-40W WITH 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE 
FROM 24N30W TO 29N38W. A THIRD WEAK SURFACE TROUGH IS IN THE 
TROPICAL ATLC ALONG 48W FROM 11N-16N. W ATLC SURFACE RIDGE WILL 
WEAKEN THROUGH MIDWEEK. A COLD FRONT WILL MOVE OFF THE SE COAST 
LATE THU. THE SURFACE TROUGH IN THE CENTRAL ATLC/E CARIBBEAN IS 
EXPECTED TO DRIFT EASTWARD. 

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

$$
PAW