000
AXNT20 KNHC 070004
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON APR 06 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 LIBERIA NEAR 6N10W TO THE EQUATOR ALONG 22W...TO 3S30W
INTO NORTHEASTERN BRAZIL NEAR 7S38W. STRONG SHOWERS IN 
INDIVIDUAL CELLS ARE FROM 1N TO 5N BETWEEN 15W AND 20W.
RANDOM AND DISORGANIZED SHOWERS ARE POSSIBLE ELSEWHERE
TO THE SOUTH OF 10N TO THE EAST OF 60W. 

...DISCUSSION...

THE GULF OF MEXICO...
BROAD MIDDLE LEVEL TO UPPER LEVEL WESTERLY WIND FLOW COVERS THE 
AREA. THE CYCLONIC FLOW THAT IS ASSOCIATED WITH THE TROUGH THAT 
IS DRIVING THE SHALLOW COLD FRONT THAT IS MOVING THROUGH THE 
AREA RIGHT NOW STILL IS ALONG AND TO THE NORTH OF 30N OVER LAND.
THE LATITUDE OF 30N SEEMS TO BE THE LINE OF CONFLUENCE THAT 
SEPARATES THE ANTICYCLONIC FLOW ACROSS THE OPEN WATERS OF THE
GULF OF MEXICO FROM THE CYCLONIC FLOW OVER LAND. THE COLD FRONT 
PASSES THROUGH 32N78W TO THE FLORIDA WEST COAST NEAR 27N83W TO
THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA INTO THE 
EASTERN ISTHMUS OF TEHUANTEPEC. GALE-FORCE WINDS ARE IN THE 
SOUTHWESTERN CORNER OF THE AREA. A DEVELOPING STORM IS FORECAST 
FOR THE GULF OF TEHUANTEPEC ON THE PACIFIC OCEAN SIDE OF MEXICO.
SHOWERS AND THUNDERSTORMS WITH THIS COLD FRONT ARE IN THE 
ATLANTIC OCEAN ARE TO THE NORTH OF 29N BETWEEN 74W AND 77W.

THE CARIBBEAN SEA...
A WEAK SURFACE PRESSURE GRADIENT EXISTS IN THE AREA FOR THIS 
MAP. A SURFACE TROUGH IS ALONG 68W/69W FROM 15N TO 18N JUST TO 
THE SOUTH OF THE SOUTHEASTERN DOMINICAN REPUBLIC. BROAD LOW 
LEVEL CYCLONIC FLOW IS SEEN IN THE LOW CLOUD FIELD...TO THE 
SOUTH OF 18N TO THE EAST OF 80W. SOME CLUSTERS OF LOW LEVEL
TO MIDDLE LEVEL CLOUDS HAVE FORMED IN THE CYCLONIC FLOW.
SOME MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW IS REACHING 
GUADELOUPE FROM THE MIDDLE LEVEL TO UPPER LEVEL ATLANTIC OCEAN
TROUGH THAT IS ALONG 31N54W 25N56W 15N58W. MIDDLE LEVEL TO UPPER 
LEVEL NORTHWESTERLY WIND FLOW MOVES ACROSS THE EDGES OF THE 
CARIBBEAN SEA. BROAD ANTICYCLONIC FLOW IS ALONG THE 80W RIDGE
THAT RUNS FROM THE SOUTHWESTERN CORNER OF THE AREA INTO THE 
SOUTHEASTERN GULF OF MEXICO.

THE ATLANTIC OCEAN...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH RUNS FROM THE WESTERN 
ATLANTIC OCEAN INTO THE CENTRAL ATLANTIC OCEAN...ALONG 31N54W
TO 25N56W TO 15N58W. ANTICYCLONIC FLOW FROM THE 80W CARIBBEAN 
SEA RIDGE SPILLS OVER INTO THE ATLANTIC OCEAN WEST OF 60W.
A SURFACE RIDGE PASSES THROUGH 34N40W TO 32N54W TO 23N67W TO 
CENTRAL CUBA NEAR 22N78W. BROAD UPPER LEVEL CYCLONIC FLOW IS 
AROUND A WEAKENING CYCLONIC CIRCULATION CENTER NEAR 28N23W. 
CYCLONIC FLOW IS TO THE NORTH OF 25N TO THE EAST OF 35W. BROAD 
LARGE-SCALE UPPER LEVEL ANTICYCLONIC FLOW IS TO THE SOUTH OF THE 
LINE FROM 13N61W IN THE SOUTHEASTERN CARIBBEAN SEA...TO 17N54W 
24N39W BEYOND 25N15W.

$$
MT