000
AXNT20 KNHC 191148
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 AM EST SAT DEC 19 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 1115 UTC.

...THE ITCZ...

FROM COASTAL SIERRA LEONE NEAR 8N13W TO 6N20W TO 3N35W 4N44W...
INTO EXTREME NORTHEASTERN BRAZIL NEAR 1N51W. SHOWERS ARE POSSIBLE
TO THE SOUTH OF 7N BETWEEN 24W AND 56W.

...DISCUSSION...

THE GULF OF MEXICO AND THE ATLANTIC OCEAN TO THE WEST OF 65W...
UPPER LEVEL SOUTHWESTERLY FLOW IS PUSHING MOISTURE FROM THE AREA 
OF 10N BETWEEN 90W AND 110W IN THE EASTERN PACIFIC OCEAN TOWARD 
THE NORTHEAST. THE UPPER LEVEL MOISTURE CROSSES MEXICO...INTO 
THE NORTH CENTRAL GULF OF MEXICO...TOWARD THE FLORIDA BIG BEND.
THE MOISTURE IN THE UPPER LEVEL SOUTHWESTERLY FLOW IS MOVING ON 
TOP OF DEEP LAYER CYCLONIC FLOW THAT COVERS AT LEAST THE 
NORTHERN HALF OF THE AREA. THE DEEP LAYER CYCLONIC FLOW IS 
STEERING THE CURRENT COLD FRONT THAT JUST MOVED ACROSS FLORIDA.
THE COLD FRONT PASSES THROUGH 31N77W IN THE ATLANTIC OCEAN...
TO GRAND BAHAMA ISLAND...TO CUBA NEAR 23N80W...INTO THE 
NORTHWESTERN CARIBBEAN SEA NEAR 20N81W. SHOWERS AND POSSIBLE 
THUNDERSTORMS ARE FROM 17N TO CUBA NEAR 20N BETWEEN WESTERN 
HAITI AND 79W...AND FROM 25N BEYOND 31N BETWEEN 69W AND 74W.
POSSIBLE SHOWERS ARE MOVING ACROSS THE SOUTHERN BAHAMAS FROM
20N TO 23N BETWEEN 72W AND 76W. SURFACE HIGH PRESSURE HAS BEEN 
BUILDING INTO THE GULF OF MEXICO TO THE WEST OF THE COLD FRONT.

THE CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW...THAT ORIGINATES OVER NORTHERN 
SECTIONS OF SOUTH AMERICA...COVERS THE AREA TO THE SOUTH OF 14N. 
UPPER LEVEL SOUTHWESTERLY WIND FLOW IS PUSHING MOISTURE FROM THE 
EASTERN PACIFIC OCEAN ACROSS CENTRAL AMERICA AND INTO THE AREA
TO THE WEST OF 77W. SHOWERS ARE POSSIBLE WITHIN 30 NM TO 60 NM
ON EITHER SIDE OF 15N60W...ACROSS DOMINICA TO 16N63W TO 20N66W.
THE SURFACE PRESSURE GRADIENT IS WEAK.
  
THE ATLANTIC OCEAN TO THE EAST OF 65W...
A DEEP LAYER TROUGH IN THE EAST CENTRAL ATLANTIC OCEAN...THAT 
PASSES THROUGH 31N34W TO 25N35W TO 18N36W 16N41W TO 15N50W...
SUPPORTS A COLD FRONT THAT PASSES THROUGH 31N35W TO 25N40W TO
22N48W. THE FRONT CONTINUES AS STATIONARY FROM 22N48W TO 21N60W 
TO 25N70W. STRONG SHOWERS AND THUNDERSTORMS ARE WITHIN 30 NM TO
60 NM ON EITHER SIDE OF 26N34W 28N30W 33N27W. MODERATE SHOWERS
ARE FROM 22N TO 25N BETWEEN 34W AND 40W. BROKEN LOW TO MIDDLE 
LEVEL CLOUDS AND POSSIBLE PRECIPITATION FROM 21N TO 23N BETWEEN 
BETWEEN 43W AND 64W...AND FROM 23N TO 27N BETWEEN 64W AND 67W.
ONE 1018 MB HIGH PRESSURE CENTER IS NEAR 23N21W. A 1016 MB HIGH 
PRESSURE CENTER IS NEAR 26N58W.

$$
MT