000
AXNT20 KNHC 131053
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON APR 13 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 1015 UTC.

...THE ITCZ...
FROM 5N6W AT THE COAST OF THE IVORY COAST...TO 2N10W...CROSSING 
THE EQUATOR ALONG 20W...TO 1S30W AND GOING INTO NORTHEASTERN 
BRAZIL NEAR 5S44W. ISOLATED AND DISORGANIZED MODERATE SHOWERS 
ARE TO THE SOUTH OF 5N TO THE EAST OF NORTHEASTERN SOUTH AMERICA.

...DISCUSSION...

THE GULF OF MEXICO...
A DEEP LAYER TROUGH FROM MISSOURI TO OKLAHOMA/ARKANSAS INTO 
CENTRAL TEXAS IS DRIVING A NORTHWESTERN-TO-NORTH CENTRAL GULF
OF MEXICO COLD FRONT. THIS COLD FRONT HAS BEEN SHRINKING IN
SIZE...MEANING THAT IT HAS BEEN DISAPPEARING AS EASTERLY WINDS
HAVE BEEN OBSERVED TO THE WEST OF THE FRONT DURING THE LAST
SIX HOURS. STRONG SHOWERS AND THUNDERSTORMS EXTEND FROM THE
SOUTHEASTERN CORNER OF MISSISSIPPI INTO CENTRAL ALABAMA.
A BLOB OF MIDDLE LEVEL TO HIGH LEVEL MOISTURE IS MOVING FROM
THE SOUTHWESTERN CORNER OF THE AREA TOWARD THE SOUTH CENTRAL 
WATERS. THE UPPER LEVEL RIDGE TO THE EAST OF THE DEEP LAYER 
TROUGH IS ALONG 85W...FROM THE GULF OF MEXICO SOUTHWARD
INTO THE WESTERN CARIBBEAN SEA.

THE CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA TO THE WEST OF
66W THANKS TO THE UPPER LEVEL 85W RIDGE THAT ALSO SPANS THE
GULF OF MEXICO. DEEP LAYER CYCLONIC FLOW CUTS INTO THE EASTERN
CARIBBEAN SEA TO THE EAST OF 66W THANKS TO THE DEEP LAYER 
WESTERN ATLANTIC OCEAN TROUGH THAT REACHES AS FAR TO THE SOUTH 
AS SAINT LUCIA. A WEAK SURFACE PRESSURE GRADIENT EXISTS ACROSS 
THE AREA. SHOWERS ARE POSSIBLE FROM 10N TO 17N BETWEEN 58W AND
62W IN CLUSTERS OF BROKEN LOW CLOUDS.
 
THE ATLANTIC OCEAN...
A WESTERN ATLANTIC OCEAN DEEP LAYER TROUGH SUPPORTS THE ATLANTIC 
OCEAN COLD FRONT THAT PASSES THROUGH THE AREA...THROUGH 32N60W 
TO 27N65W TO 24N71W. ISOLATED MODERATE SHOWERS ARE IN TWO LINES
IN FRONT OF THE COLD FRONT...TO THE NORTH OF 23N BETWEEN 55W AND 
63W. BROAD SURFACE ANTICYCLONIC FLOW IS TO THE NORTH OF 15N 
BETWEEN AFRICA AND 60W. AN UPPER LEVEL RIDGE IS ALONG 32N20W TO 
32N54W. BROAD LARGE-SCALE UPPER LEVEL ANTICYCLONIC FLOW IS TO 
THE SOUTH OF 26N TO THE EAST OF 60W. 

$$
MT