000
AXNT20 KNHC 071717
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC.

...THE ITCZ...
FROM SOUTHERN LIBERIA NEAR 5N10W TO 2N20W...CROSSING THE EQUATOR 
ALONG 26W...TO 2S30W INTO NORTHEASTERN BRAZIL NEAR 5S43W. 
ISOLATED AND DISORGANIZED MODERATE SHOWERS ARE SOUTH OF 7N 
BETWEEN 7W AND 37W.

...DISCUSSION...

THE GULF OF MEXICO...
THE DEEP LAYER TROUGH THAT HAS BEEN DRIVING THE CURRENT COLD 
FRONT THAT JUST MOVED THROUGH THE GULF OF MEXICO HAS BEEN MOVING 
MORE AND MORE TO THE SOUTH WITH TIME. CYCLONIC FLOW AROUND THE 
BASE OF THE TROUGH NOW MOVES ACROSS 90W INTO THE EASTERN GULF OF 
MEXICO. A WEAK UPPER LEVEL RIDGE IS LINED UP WITH THE COASTLINE 
FROM MEXICO NEAR 20N TO THE MIDDLE TEXAS COAST. THE COLD FRONT 
HAS MOVED ACROSS AND OUT OF THE GULF AREA. IT NOW STRETCHES FROM 
THE NORTHERN PART OF THE BAHAMAS TO WESTERN CUBA TO SOUTHERN 
BELIZE AND SOUTHWESTERN GUATEMALA. MIDDLE LEVEL TO UPPER LEVEL
DRY AIR IN SUBSIDENCE IS TO THE NORTH OF 27N.

THE CARIBBEAN SEA...
MOSTLY MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC FLOW COVERS THE 
OPEN WATERS OF THE AREA. UPPER LEVEL SOUTHERLY TO SOUTHWESTERLY
WINDS MOVE FROM SOUTH AMERICA AND CURVE NORTHWARD AND
NORTHEASTWARD TO THE SOUTH OF DOMINICA IN THE EASTERN CARIBBEAN
SEA ISLANDS. A WEAK SURFACE PRESSURE GRADIENT EXISTS IN THE AREA
FOR THIS MAP. A SURFACE TROUGH IS ALONG 14N64W 16N65W 18N65W.
BROAD LOW LEVEL CYCLONIC FLOW IS SEEN IN THE LOW CLOUD FIELD.
INDIVIDUAL CLUSTERS OF CLOUDS AND POSSIBLE SHOWERS ARE FROM 15N
TO 18N BETWEEN 64W AND 67W. THE SOUTHERN PART OF THE CURRENT
ATLANTIC OCEAN COLD FRONT PASSES ACROSS WESTERN CUBA TO SOUTHERN
BELIZE AND SOUTHWESTERN GUATEMALA. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE IN THE
NORTHWESTERN CORNER OF THE AREA.

THE ATLANTIC OCEAN...
THE CURRENT COLD FRONT PASSES THROUGH 32N71W TO THE BAHAMAS NEAR
26N77W NEAR THE SOUTHERN END OF ABACO...TO WESTERN CUBA NEAR 
23N81W. ISOLATED MODERATE SHOWERS ARE WITHIN 30 NM TO 60 NM
ON EITHER SIDE OF 24N75W 28N71W BEYOND 32N70W. MIDDLE LEVEL TO 
UPPER LEVEL TROUGH RUNS FROM 31N44W IN THE CENTRAL ATLANTIC 
OCEAN TO 21N51W TO 10N55W...UNDER THE UPPER LEVEL SOUTHWESTERLY 
WIND FLOW THAT ULTIMATELY IS MOVING AWAY FROM SOUTH AMERICA.
A REMNANT MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION 
CENTER IS NEAR 26N17W TO THE WEST OF THE WESTERN SAHARA AND
TO THE SOUTH OF THE CANARY ISLANDS. A SURFACE RIDGE EXTENDS FROM 
A 1031 MB HIGH PRESSURE CENTER NEAR 35N29W TO 32N38W TO 27N50W 
TO 23N60W.

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MT