000
AXNT20 KNHC 242359
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU DEC 24 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...THE ITCZ...

FROM 5N4W AT THE IVORY COAST TO 2N20W TO 2N42W INTO NORTHEASTERN
BRAZIL AT 50W ALONG THE EQUATOR. STRONG SHOWERS AND THUNDERSTORMS
ARE WITHIN A 30 NM TO 45 NM RADIUS OF 2N28W. ISOLATED MODERATE 
SHOWERS AND POSSIBLE THUNDERSTORMS...SOME DISSIPATING WITH 
TIME...TO THE SOUTH OF 6N BETWEEN 10W AND 54W NEAR THE COAST
OF FRENCH GUIANA.

...DISCUSSION...

THE GULF OF MEXICO...
A VIGOROUS DEEP LAYER TROUGH IS MOVING THROUGH THE AREA THAT IS 
COVERED BY SOUTHEASTERN OKLAHOMA...EASTERN TEXAS...SOUTHWESTERN 
ARKANSAS...AND WESTERN LOUISIANA...INTO THE NORTHWESTERN GULF OF 
MEXICO NEAR 25N96W. A COLD FRONT PASSES THROUGH SOUTHEASTERN
LOUISIANA INTO THE GULF OF MEXICO NEAR 27N92W AND 23N95W. A WARM
FRONT/STATIONARY FRONT EXTENDS FROM THE TRIPLE POINT IN 
NORTHEASTERN LOUISIANA TO THE FLORIDA PANHANDLE TO NORTHEASTERN 
FLORIDA. THE COLD FRONT CLEARLY IS MARKED BY A ROPE-CLOUD IN 
SATELLITE IMAGERY. RAINSHOWERS ARE FROM 25N TO 26N BETWEEN 89W 
AND 90W...AND FROM 27N NORTHWARD BETWEEN 87W AND 91W. THE FRONT 
IS FORECAST TO MOVE THROUGH THE EASTERN GULF OF MEXICO AND 
FLORIDA BY SATURDAY MORNING.

THE CARIBBEAN SEA...
A 1011 MB LOW PRESSURE CENTER IS IN THE ATLANTIC OCEAN NEAR
23N70W. A TROUGH TRAILS FROM THE LOW CENTER TO EASTERN COASTAL
DOMINICAN REPUBLIC NEAR 69W...INTO THE CARIBBEAN SEA NEAR 
15N72W. STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 
EXTREME EASTERN COASTAL DOMINICAN REPUBLIC...INTO THE MONA 
PASSAGE...TO EXTREME NORTHWESTERN COASTAL PUERTO RICO. OTHER 
SHOWERS ARE MOVING ACROSS PUERTO RICO FROM CENTRAL SECTIONS INTO 
THE EASTERN PART OF THE ISLAND. SCATTERED MODERATE SHOWERS AND 
ISOLATED STRONG THUNDERSTORMS ARE IN THE ATLANTIC OCEAN FROM 20N 
TO 23N BETWEEN 60W AND 68W. A MIDDLE LEVEL TO UPPER LEVEL TROUGH 
RUNS FROM THE CENTER OF THE CARIBBEAN SEA TO ITS BASE THAT IS IN
PANAMA BETWEEN 80W AND THE BORDER WITH COSTA RICA. UPPER LEVEL 
ANTICYCLONIC FLOW COVERS THE AREA TO THE EAST OF THE LINE FROM 
NORTHEASTERN COASTAL COLOMBIA TO THE VIRGIN ISLANDS.

THE ATLANTIC OCEAN...
A 1011 MB LOW PRESSURE CENTER IS IN THE ATLANTIC OCEAN NEAR 
23N70W. A TROUGH TRAILS FROM THE LOW CENTER TO EASTERN COASTAL 
DOMINICAN REPUBLIC NEAR 69W...INTO THE CARIBBEAN SEA NEAR 
15N72W. A WARM FRONT GOES FROM THE LOW CENTER TO 25N69W AND 
24N62W. STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 
EXTREME EASTERN COASTAL DOMINICAN REPUBLIC...INTO THE MONA 
PASSAGE...TO EXTREME NORTHWESTERN COASTAL PUERTO RICO. OTHER 
SHOWERS ARE MOVING ACROSS PUERTO RICO FROM CENTRAL SECTIONS INTO 
THE EASTERN PART OF THE ISLAND. SCATTERED MODERATE SHOWERS AND 
ISOLATED STRONG THUNDERSTORMS ARE IN THE ATLANTIC OCEAN FROM 20N 
TO 23N BETWEEN 60W AND 68W. A MIDDLE LEVEL TO UPPER LEVEL TROUGH
PASSES OVER BERMUDA TO 26N70W. DRY AIR IN SUBSIDENCE IS WITHIN
180 NM TO 240 NM ON EITHER SIDE OF THE TROUGH ON WATER VAPOR 
IMAGERY. AN EASTERN ATLANTIC OCEAN MIDDLE LEVEL TO UPPER LEVEL 
TROUGH EXTENDS FROM 36N30W...THROUGH 32N26W...TO 31N25W REACHING
24N26W. FRONTAL BOUNDARIES ARE TO THE NORTH OF THE AREA.
A SURFACE TROUGH IS ALONG 27W FROM 23N BEYOND 32N.

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

$$
MT