000
AXNT20 KNHC 211145
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED JAN 21 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 6N9W IN LIBERIA TO THE EQUATOR ALONG 22W TO 3S33W INTO 
NORTHEASTERN BRAZIL NEAR 4S39W. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE FROM 1S TO 1N BETWEEN 27W AND 40W. ISOLATED
MODERATE SHOWERS TO POSSIBLE THUNDERSTORMS ARE ELSEWHERE
SOUTH OF 5N.
 
...DISCUSSION...

THE GULF OF MEXICO AND THE ATLANTIC OCEAN WEST OF 70W...
A DEEP-LAYER TROUGH SUPPORTS THE MOST RECENT COLD FRONT TO VISIT
THE AREA. THE FRONT NOW IS IN THE ATLANTIC OCEAN...PASSING 
THROUGH 32N67W...ACROSS GREAT EXUMA IN THE BAHAMAS...ACROSS 
CENTRAL CUBA TO NORTHERN BELIZE. THIS COLD FRONT HAS BROUGHT TO 
THE SOUTHEASTERN U.S.A. THE FIRST SIGNIFICANT SHOT OF COLD AIR 
FOR THE 2008-2009 WINTER SEASON. CYCLONIC FLOW ON WATER VAPOR 
IMAGERY COVERS THE ENTIRE AREA. GALE WIND CONDITIONS ARE 
FORECAST IN THE ATLANTIC OCEAN NORTH OF 30N WITHIN 240 NM TO THE 
EAST OF THE FRONT FOR THE NEXT 12 HOURS OR SO...AND WIND SPEEDS 
RANGING FROM 20 KT TO 30 KT ELSEWHERE ON BOTH SIDES OF THE FRONT 
FOR THE NEXT 48 HOURS.

THE CARIBBEAN SEA...
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA...AROUND
A RIDGE ALONG 65W/66W. MIDDLE TO UPPER LEVEL CYCLONIC FLOW IS 
ADVANCING EASTWARD FROM THE ATLANTIC OCEAN INTO THE AREA JUST
TO THE EAST OF THE EASTERN CARIBBEAN SEA ISLANDS. THE SOUTHERN 
END OF THE ATLANTIC OCEAN COLD FRONT CUTS ACROSS CENTRAL CUBA
TO THE NORTHERN BELIZE. ONE CLOUD LINE THAT STRETCHES FROM 
SOUTHEASTERN CUBA TO THE NORTHEASTERN CORNER OF NICARAGUA
MARKS A TROUGH/REMNANT FRONTAL BOUNDARY. A SECOND CLOUD LINE 
THAT PASSES FROM HAITI/THE WINDWARD PASSAGE TO THE SOUTHWESTERN 
CORNER OF THE AREA MARKS A SECOND TROUGH/REMNANT FRONTAL 
BOUNDARY FROM AT LEAST A FEW DAYS AGO. POSSIBLE SHOWERS 
ACCOMPANY THESE CLOUD LINES/TROUGHS. 

THE REST OF THE ATLANTIC OCEAN EAST OF 70W...
A SURFACE TROUGH/REMNANT FRONTAL BOUNDARY WITH LESS AND LESS 
UPPER LEVEL SUPPORT AS IT HAD EARLIER...IS ALONG 31N60W TO THE 
CAICOS ISLANDS BEYOND WESTERN HAITI. A DEFINITE CLOUD LINE WITH 
POSSIBLE SHOWERS MARKS THIS BOUNDARY. A SURFACE RIDGE GOES FROM 
A 1032 MB HIGH PRESSURE CENTER NEAR 31N32W TO 28N45W TO 24N59W
TO 22N69W. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER
IS NEAR 15N53W. BROAD CYCLONIC FLOW IS FROM 8N TO 25N BETWEEN 
40W AND 60W. THIS CUT-OFF CYCLONE IS MOVING UNDER AN UPPER LEVEL 
LEVEL RIDGE ALONG 42W. A MIDDLE TO UPPER LEVEL TROUGH PASSES 
FROM ALGERIA TO MAURITANIA AND MALI TO 11N17W WEST OF GUINEA.

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