000
AXNT20 KNHC 091158
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 09 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE 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

...SPECIAL FEATURE...
A SUBTROPICAL CLASSIFICATION OF ST1.5 WAS ASSIGNED TO A LOW TO 
MIDDLE LEVEL CYCLONIC CIRCULATION NEAR 18N54W. A SURFACE TROUGH 
IS ALONG 53W/54W FROM 14N TO 23N. LARGE-SCALE MIDDLE TO UPPER 
LEVEL CYCLONIC FLOW AROUND THIS FEATURE ON WATER VAPOR IMAGERY
COVERS THE ATLANTIC OCEAN AND CARIBBEAN SEA FROM COLOMBIA
AND VENEZUELA ALONG 8N TO 25N BETWEEN 47W AND 80W. A MIDDLE
TO UPPER LEVEL TROUGH GOES FROM 22N52W TO 12N63W TO THE 
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. ISOLATED TO WIDELY
SCATTERED MODERATE SHOWERS/LOCALLY STRONG THUNDERSTORMS FROM 
FROM 18N TO 23N BETWEEN 50W AND 60W. ISOLATED MODERATE SHOWERS 
FROM 20N TO 22N BETWEEN 60W AND 65W. ISOLATED MODERATE SHOWERS 
FROM 14N TO 17N BETWEEN 46W AND 48W. ISOLATED MODERATE SHOWERS 
ARE IN THE CARIBBEAN SEA FROM 10N TO 16N BETWEEN 64W AND 72W.

...THE ITCZ...
8N13W 6N30W 4N54W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG
THUNDERSTORMS FROM 5N TO 7N BETWEEN 26W AND 38W...AND SOUTH OF
10N BETWEEN 47W AND 60W. ISOLATED MODERATE SHOWERS SOUTH OF 5N 
EAST OF 40W. STRONG SHOWERS/THUNDERSTORMS IN CELLS FROM 10N
TO 12N BETWEEN 42W AND 44W POSSIBLY IN AN AREA OF MIDDLE TO 
UPPER LEVEL DIFFLUENT WIND FLOW.

DISCUSSION...
THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL MOISTURE MOVES FROM THE EASTERN PACIFIC
OCEAN ACROSS MEXICO INTO TEXAS AND BEYOND...WITHIN 300 NM ON
EITHER SIDE OF 10N121W 22N106W BEYOND 27N99W. MIDDLE TO UPPER 
LEVEL CYCLONIC WIND FLOW WITH A TROUGH COVERS CALIFORNIA AND 
BAJA CALIFORNIA...NORTHERN MEXICO...AND THE SOUTHWESTERN U.S.A.
A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM THE NORTHEASTERN
CORNER OF THE AREA TO THE SOUTHWESTERN CORNER...SURROUNDED BY
MIDDLE TO UPPER LEVEL DRY AIR.

THE CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC WIND FLOW FROM A RIDGE COVERS THE AREA 
WEST OF 80W. BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW AND DRY 
AIR/SUBSIDENCE COVER THE AREA EAST OF 80W. ISOLATED MODERATE 
SHOWERS ARE EAST OF 74W.

THE ATLANTIC OCEAN...
THE UPPER LEVEL RIDGE IN THE EASTERN GULF OF MEXICO FROM
24 HOURS AGO HAS MOVED EASTWARD AND NOW IS PRIMARILY ALONG 78W. 
A LARGE SECTION OF THE ATLANTIC OCEAN IS TAKEN UP BY THE 
SUBTROPICAL SYSTEM AT THE LOW TO MIDDLE LEVELS NEAR 18N54W.
THE CARIBBEAN SEA EAST OF 80W HAS BROAD CYCLONIC FLOW AND 
ISOLATED MODERATE SHOWERS. THE CYCLONIC FLOW AROUND THE 30N35W 
MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER COVERS THE 
AREA FROM 20N TO 34N BETWEEN 27W AND 42W. BROAD MIDDLE TO UPPER 
LEVEL CYCLONIC FLOW COVERS AFRICA NORTH OF 16N EAST OF 20W.

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