000
AXNT20 KNHC 210005
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON APR 20 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 THE LIBERIA COAST NEAR 6N10W TO THE EQUATOR ALONG 19W
TO 5S30W INTO NORTHEASTERN BRAZIL NEAR 6S35W. NO SIGNIFICANT
DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THE ITCZ.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW MOVES FROM NORTHERN 
MEXICO AND WEST TEXAS ACROSS THE LOWER RIO GRANDE VALLEY...
INTO THE WEST CENTRAL GULF OF MEXICO...AND THEN IT SWINGS 
NORTHEASTWARD ACROSS NORTHERN FLORIDA. DEEP LAYER MOISTURE
MOVES FROM THE YUCATAN PENINSULA NORTHEASTWARD ACROSS MOST OF 
FLORIDA...TO THE SOUTH OF 30N TO THE EAST OF 84W. ISOLATED 
MODERATE SHOWERS ARE IN THIS AREA OF DEEP LAYER MOISTURE.
THE COLD FRONT PASSES THROUGH NORTHERN FLORIDA TO THE 
SOUTHWESTERN GULF OF MEXICO...JUST TO THE WEST OF THE YUCATAN 
PENINSULA. A SURFACE TROUGH IS WITHIN 120 NM TO THE EAST OF THE 
COLD FRONT TO THE NORTH OF 26N.

THE CARIBBEAN SEA... 
BROAD MIDDLE TO UPPER LEVEL NORTHWESTERLY-TO-WESTERLY WIND FLOW 
COVERS THE ENTIRE AREA. UPPER LEVEL SOUTHWESTERLY WIND FLOW
MOVES FROM EXTREME NORTHWESTERN VENEZUELA ACROSS THE REST OF
THE CARIBBEAN SEA...AND EXITS THE AREA AS IT PASSES ON TOP OF 
THE EASTERN CARIBBEAN SEA ISLANDS...FROM THE GUADELOUPE PASSAGE 
SOUTHWARD. 

THE ATLANTIC OCEAN...
LARGE-SCALE UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA 
TO THE WEST OF 50W. A CENTRAL ATLANTIC OCEAN DEEP LAYER TROUGH 
THAT PASSES THROUGH 32N44W TO 24N46W TO 19N50W TO 16N55W 
SUPPORTS A FRONTAL BOUNDARY THAT IS COLD FROM 31N47W TO 27N50W 
TO 23N56W. THE FRONT BECOMES STATIONARY AT 23N56W AND CONTINUES 
TO THE DOMINICAN REPUBLIC NEAR 19N70W. A TROUGH CONTINUES FROM 
19N70W TO 20N78W ALONG THE COAST OF CUBA. A SEPARATE TROUGH 
EXTENDS FROM A 1018 MB LOW PRESSURE CENTER NEAR 29N53W TO
A SECOND 1018 MB LOW PRESSURE CENTER NEAR 27N55W TO 22N60W 
21N67W CURVING TO THE BAHAMAS NEAR 24N75W. LINES OF CLOUDS AND
POSSIBLE SHOWERS IN THOSE CLOUDS MARK THE FRONTAL BOUNDARY AND
THE SURFACE TROUGH. AN UPPER LEVEL RIDGE PASSES THROUGH 32N36W
TO 21N49W TO 27N42W BEYOND A 1033 MB HIGH PRESSURE CENTER NEAR
35N24W. AN UPPER LEVEL TROUGH EXTENDS FROM A BROAD CYCLONIC
CIRCULATION CENTER NEAR 27N21W TO 12N23W TO 5N25W.

$$
MT