000
AXNT20 KNHC 141115
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 AM EST SUN DEC 13 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1045 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N4W 5N14W 2N30W 1S47W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-6N 
BETWEEN 5W-15W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A WARM FRONT DRAPES ACROSS THE NRN GULF 
COASTLINE FROM TALLAHASSEE FLORIDA ACROSS SE LOUISIANA ALONG THE 
TEXAS COAST TO NEAR CORPUS CHRISTI. RADAR IMAGERY ALONG WITH 
RECENT LIGHTNING DATA INDICATE ISOLATED SHOWERS/THUNDERSTORMS 
WITHIN 60 NM OF THE FRONT AXIS. A SURFACE TROUGH IS ANALYZED IN 
THE SW CARIBBEAN FROM 25N92W TO 21N93W. SCATTERED 
SHOWERS/THUNDERSTORMS ARE FROM 24N-25N BETWEEN 90W-92W. MOIST 
SWLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE W CARIBBEAN 
IS DRAWING MOISTURE NE SUPPORTING THE SHOWER ACTIVITY NEAR THE 
FRONT. SURFACE RIDGING EXTENDS S OF THE FRONT FROM THE E 
CENTERED N OF TAMPA FLORIDA NEAR A 1020 MB HIGH NEAR 28N83W 
SUPPORTING GENERALLY FAIR WEATHER ACROSS THE REMAINDER OF THE 
AREA. EXPECT THE FRONT TO BECOME DIFFUSE WITHIN THE NEXT 24 HRS 
AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE E AND CENTRAL 
GULF.

CARIBBEAN SEA...
FRESH TO STRONG TRADEWINDS CONTINUE ACROSS THE CARIBBEAN DUE 
TO A RELATIVITY STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE 
OVER THE W ATLC AND LOW PRESSURE OVER NRN S AMERICA. GALE FORCE 
WINDS ARE NOTED OFF THE COAST OF COLOMBIA. WATER VAPOR IMAGERY 
INDICATES STRONG SUBSIDENCE ACROSS THE BASIN AROUND AN UPPER 
LEVEL RIDGE CENTERED S OF CUBA. HOWEVER...ISOLATED SHOWERS ARE 
ACROSS PORTIONS OF THE BASIN INCLUDING PUERTO 
RICO...HISPANIOLA...AND N OF HONDURAS. EXPECT THE GALE FORCE 
WINDS TO CONTINUE FOR THE NEXT 24 HRS. 

ATLANTIC OCEAN...
A SHORTWAVE UPPER LEVEL TROUGH OFF THE NE UNITED STATES COAST 
ALONG 65W SUPPORTS A FRONTAL BOUNDARY EXTENDING OFF THE ERN 
SEABOARD TO N FLORIDA. DIFFLUENT FLOW ALOFT E OF THE UPPER 
TROUGH...ALONG WITH SURFACE CONVERGENCE NEAR THE FRONT IS 
SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS N OF 28N BETWEEN 
65W-71W. ELSEWHERE ACROSS THE W ATLC...HIGH PRESSURE DOMINATES 
ANCHORED BY A 1026 MB HIGH NEAR 34N59W BRINGING GENERALLY FAIR 
WEATHER ACROSS THE AREA. THE SURFACE HIGH IS SUPPORTED BY AN 
UPPER LEVEL RIDGE EXTENDING FROM THE W CARIBBEAN INTO THE W 
ATLC. FARTHER E...A COLD FRONT EXTENDS FROM THE AZORES ISLANDS 
ENTERING THE DISCUSSION AREA NEAR 32N29W CONTINUING ALONG 26N38W 
20N53W. SCATTERED SHOWERS ARE WITHIN 90 NM BEHIND...150 NM AHEAD 
OF THE FRONT N OF 26N WITH ISOLATED SHOWERS POSSIBLE ALONG THE 
REMAINDER OF THE FRONT. THE BOUNDARY IS SUPPORTED BY AN UPPER 
LEVEL TROUGH WITH AXIS ALONG 38W. A WEAK SURFACE RIDGE IS SE OF 
THE FRONT ANCHORED BY A 1015 MB HIGH NEAR 24N21W.

$$
WALTON