000
AXNT20 KNHC 281731
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 28 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM SIERRA LEONE AT 8N13W TO 6N16W. 
THE ITCZ AXIS CONTINUES TO N BRAZIL ALONG 6N16W 2N37W 1N50W. 
ISOLATED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 2W-14W. 
WIDELY SCATTERED MODERATE CONVECTION IS FROM 1N-8N BETWEEN 
17W-25W. 

...DISCUSSION...

GULF OF MEXICO...

A 1023 MB HIGH IS CENTERED OVER SE LOUISIANA NEAR 30N91W. 5-10 
KT ANTICYCLONIC FLOW WITH FAIR WEATHER IS OVER THE GULF OF 
MEXICO N OF 20N. COLD AIR ADVECTION PERSISTS OVER FLORIDA WHILE 
A WARMING TREND IS OVER S TEXAS. BROKEN TO OVERCAST SKIES WITH 
SCATTERED SHOWERS ARE OVER THE BAY OF CAMPECHE AND S MEXICO S OF 
20N BETWEEN 92W-97W. IN THE UPPER LEVELS...MOSTLY ZONAL FLOW IS 
OVER THE GULF WITH CONSIDERABLE UPPER LEVEL MOISTURE OVER THE NW 
GULF AND STRONG SUBSIDENCE ELSEWHERE. EXPECT OVER THE NEXT 24 
HOURS FOR THE SURFACE HIGH TO MOVE E TO N FLORIDA ...AND FOR 
ANOTHER HIGH TO MOVE OVER S TEXAS WITH MOSTLY FAIR WEATHER. 
SCATTERED SHOWERS WILL PERSIST OVER THE BAY OF CAMPECHE AND THE 
YUCATAN PENINSULA.

CARIBBEAN SEA...

20-25 KT TRADEWINDS ARE OVER THE CENTRAL AND EASTERN CARIBBEAN  
E OF 80W WITH STRONGEST WINDS ALONG THE COAST OF N 
COLOMBIA. IN CONTRAST 10-15 KT TRADEWINDS ARE OVER THE W 
CARIBBEAN WITH LIGHTEST WINDS OVER THE GULF OF HONDURAS.  
PATCHES OF BROKEN LOW CLOUDS WITH SCATTERED SHOWERS DOTS THE 
CARIBBEAN MOVING W WITH THE TRADEWINDS ESPECIALLY OVER THE 
LEEWARD ISLANDS...PUERTO RICO...AND S OF HISPANIOLA. SIMILAR 
SHOWERS ARE INLAND OVER CENTRAL AMERICA FROM PANAMA TO BELIZE. 
IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE CARIBBEAN 
WITH AXIS ALONG 70W. STRONG SUBSIDENCE COVERS THE CARIBBEAN AND 
CENTRAL AMERICA SUPPRESSING ALL DEEP CONVECTION. EXPECT IN 24 
HOURS FOR...ADDITIONAL SHOWERS TO BE OVER THE S CARIBBEAN S OF 
13N...AND OVER THE NW CARIBBEAN N OF BELIZE. 

ATLANTIC OCEAN...

AT 1500 UTC...A COLD FRONT IS OVER THE W ATLANTIC FROM 30N70W TO 
THE CENTRAL BAHAMAS AT 24N75W TO CENTRAL CUBA AT 23N79W. 
OVERCAST LOW CLOUDS ARE WITHIN 120 NM NW OF THE FRONT WITH 
SCATTERED SHOWERS WITHIN 30 NM. A 1024 MB HIGH IS OVER THE W 
ATLANTIC NEAR 26N55W. A COLD FRONT IS OVER THE CENTRAL ATLANTIC 
FROM 30N43W TO 26N46W 24N52W. A PREFRONTAL TROUGH IS ALONG 
30N41W 24N45W. BROKEN TO OVERCAST LOW CLOUDS AND SCATTERED 
SHOWERS ARE N OF 25N BETWEEN 40W-43W. 30 KT WINDS ARE N OF 30N 
ALONG AND W OF THE FRONT WITH GALE FORCE WINDS FURTHER N. AN 
UPPER LEVEL LOW IS CENTERED N OF THE CAPE VERDE ISLANDS NEAR 
22N24W PRODUCING SCATTERED RAIN AND SHOWERS NEAR THE LOW CENTER 
AND FURTHER E DUE TO UPPER LEVEL DIFFLUENCE. EXPECT IN 24 HOURS 
FOR...THE W ATLANTIC COLD FRONT TO EXTEND FROM 30N60W TO THE 
CENTRAL BAHAMAS STRAITS OF WITH RAIN AND SHOWERS. ALSO EXPECT 
THE CENTRAL ATLANTIC FRONT TO BECOME QUASI-STATIONARY WITH 
SHOWERS.      

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

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FORMOSA