000
AXNT20 KNHC 251744
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST FRI DEC 25 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 1730 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N13W 3N30W EQ49W. SCATTERED 
WEAK TO MODERATE CONVECTION IS 70 NM NORTH OF THE EQUATOR 
BETWEEN 10W AND 30W.

...DISCUSSION...

THE GULF OF MEXICO...
HEAVY SHOWERS AND THUNDERSTORMS ARE MOVING ACROSS THE STATE OF 
FLORIDA. A COLD FRONT IS ANALYZED ALONG 30N80W 27N82W 25N82W 
22N84W...MOVING EASTWARD AT ABOUT 20 KT. FROM DOPPLER RADAR 
IMAGERY...THIS COLD FRONT IS PRODUCING A LINE OF HEAVY SHOWERS 
AND THUNDERSTORMS IN ITS PATH...CURRENTLY AFFECTING THE 
SOUTH-SOUTHWEST FLORIDA COAST...THE FLORIDA STRAIGHTS...AND 
WESTERN CUBA. WESTERLY 15 TO 25 KT WINDS ARE OBSERVED BEHIND THE 
FRONT...WHILE SOUTHERLY 10 TO 20 KT WINDS ARE OBSERVED AHEAD OF 
THE FRONT. SATELLITE IMAGERY SHOWS CLEARING OVER THE NW BASIN AS 
SURFACE HIGH PRESSURE BUILDS OVER THIS REGION. THIS HIGH 
PRESSURE IS EXPECTED TO MOVE TO THE NORTH CENTRAL BASING OVER 
THE NEXT 24 HOURS. SOUTHWEST FLOW IN THE UPPER LEVELS IS MOVING 
MOISTURE ALOFT ACROSS THE GULF. LOOK FOR THE COLD FRONT TO 
CONTINUE TO MOVE EAST...COMING OUT OF THE GULF OVER THE NEXT 24 
HOURS. 

THE CARIBBEAN SEA...
UPPER LEVEL RIDGE OF HIGH PRESSURE HAS SETTLED OVER THE WESTERN 
CARIBBEAN SEA...MAKING THE SURFACE PRESSURE GRADIENT TO EXPAND 
OVER MOST OF THE WESTERN BASIN AND CENTRAL AMERICA. 
THEREFORE...LIGHT TRADEWINDS ARE OBSERVED OVER THE WEST AND 
CENTRAL BASIN. A TROUGH IS ANALYZED OVER THE NE BASIN FROM 
21N61W CROSSING THE ISLAND OF PUERTO RICO TO NEAR 16N68W. 
MODERATE TO STRONG CONVECTION IS FOUND 100 NM EAST OF THE 
TROUGH...AFFECTING THE NORTHERN LEEWARD ISLANDS NORTH OF 16N 
BETWEEN 60W AND 64W. WINDS IN THIS REGION ARE FROM THE 
EAST-SOUTHEAST AT 15 TO 20 KT. THIS TROUGH IS MOVING EASTWARD 
OUT OF THE CARIBBEAN SEA INTO THE ATLANTIC OCEAN OVER THE NEXT 
24 HOURS. HIGH PRESSURE WILL DOMINATE THE ENTIRE CARIBBEAN SEA 
FOR THE NEXT FEW DAYS...BRINGING FAIR WEATHER TO THE REGION.

THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH IS MOVING OVER THE CENTRAL 
ATLANTIC...FEEDING MOISTURE TO A 992 MB LOW NEAR 36N50W. A COLD 
FRONT EXTENDS SW FROM THE CENTER LOW AND ENTERS THE DISCUSSION 
AREA ALONG 30N47W 25N52W 20N60W. A WEAK SURFACE LOW IS PLOTTED 
EAST OF THE BAHAMAS NEAR 21N65W. THIS LOW IS BLENDING WITH THE 
CITED COLD FRONT...BRINGING SCATTERED MODERATE TO STRONG 
CONVECTION NORTH OF THE LEEWARD ISLANDS FROM 16N TO 22N BETWEEN 
57W-64W. THIS FRONT WILL CONTINUE TO MOVE EASTWARD LEAVING GALE 
FORCE WINDS BEHIND ITS PATH. A 1016 MB HIGH IS OVER THE CENTRAL 
ATLANTIC NEAR 19N37W...BRINGING MOSTLY FAIR WEATHER TO THE 
CENTRAL AND TROPICAL REGION. EXPECT IN 24 HOURS FOR A COLD FRONT 
TO MOVE OUT OF FLORIDA AND ENTER THE DISCUSSION AREA OVER THE 
WEST ATLANTIC WITH CONVECTION IN THIS REGION.  

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

$$

GARCIA