000
AXNT20 KNHC 171753
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST THU DEC 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N13W 5N20W 6N40W 3N51W. 
SCATTERED SHOWERS ARE WITHIN 90 NM OF THE AXIS.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A 1026 MB HIGH IS CENTERED OVER N MEXICO NEAR 
27N101W. A 1012 MB LOW IS OVER THE NW GULF OF MEXICO NEAR 
27N95W. A TIGHT SURFACE PRESSURE GRADIENT IS OVER THE NW GULF OF 
MEXICO PRODUCING GALE FORCE WINDS FROM 26N-28N W OF 92W... 
AND S OF 22N W OF 93W. A STATIONARY FRONT EXTENDS E FROM THE LOW 
CENTER TO CENTRAL FLORIDA ALONG 28N88W 28N80W. A STATIONARY 
FRONT ALSO EXTENDS S FROM THE LOW CENTER TO THE BAY OF CAMPECHE 
TO 18N93W. SCATTERED MODERATE CONVECTION IS FROM 24N-29N BETWEEN 
88W-93W...AND FROM 20N-22N BETWEEN 91W-93W. RADAR ALSO SHOWS 
RAIN AND SHOWERS OVER THE NW GULF EXTENDING 120 NM OFF THE COAST 
BETWEEN 87W-97W. IN THE UPPER LEVELS...THE BACK SIDE OF AN UPPER 
LEVEL RIDGE IS PRODUCING SW FLOW OVER THE ENTIRE GULF OF MEXICO. 
SIGNIFICANT UPPER LEVEL MOISTURE IS OVER THE GULF. EXPECT...THE 
GALE LOW TO DEEPEN TO 1002 MB AND MOVE NE TO THE COAST OF N 
FLORIDA NEAR 28N86W IN 24 HOURS WITH CONVECTION. 

CARIBBEAN SEA...
STRONG ELY TRADEWINDS CONTINUE ACROSS THE CARIBBEAN. STRONGEST 
WINDS REMAIN NEAR THE COASTS OF COLOMBIA AND VENEZUELA. PATCHES 
OF BROKEN LOW CLOUDS WITH ISOLATED SHOWERS DOTS THE CARIBBEAN 
NAMELY OVER THE CENTRAL AND EASTERN CARIBBEAN E OF 78W...AND THE 
W CARIBBEAN AND CENTRAL AMERICA W OF 84W. IN THE UPPER LEVELS... 
MOSTLY ZONAL FLOW IS OVER THE CARIBBEAN. VERY STRONG SUBSIDENCE 
IS ACROSS THE BASIN SUPPRESSING DEEP CONVECTION. EXPECT... 
CONVECTION OVER THE NW CARIBBEAN OVER THE NEXT 24 HOURS. ALSO 
EXPECT THE TRADEWINDS AND SHOWERS TO PERSIST WITH LITTLE 
CHANGE.   

ATLANTIC OCEAN...
A COLD FRONT IS OVER THE NW ATLANTIC FROM 32N50W TO 26N60W 
26N72W. A STATIONARY FRONT CONTINUES TO CENTRAL FLORIDA NEAR 
28N80W. SCATTERED SHOWERS ARE 90 NM N OF THE FRONT. A 994 MB LOW 
IS OVER THE E ATLANTIC NEAR 34N23W. A COLD FRONT EXTENDS S TO 
26N25W 21N34W. SCATTERED MODERATE CONVECTION IS E OF THE FRONT 
AND W OF THE CANARY ISLANDS FROM 24N-30N BETWEEN 18W-22W. IN THE 
UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W ATLANTIC W OF 
70W. A BROAD UPPER LEVEL TROUGH IS OVER THE CENTRAL AND EASTERN 
ATLANTIC BETWEEN 15W-55W. EXPECT...BOTH COLD FRONTS TO MOVE E  
OVER THE NEXT 24 HOURS WITH SHOWERS AND CONVECTION.  

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

$$
FORMOSA