000
AXNT20 KNHC 110531
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON MAY 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N10W 3N20W 1N30W CROSSING THE 
EQUATOR NEAR 32W AND INTO NE BRAZIL NEAR 3S40W. ISOLATED 
MODERATE CONVECTION IS ALONG THE COAST OF W AFRICA FROM 5N-7N 
BETWEEN 10W-12W. SIMILAR CONVECTION IS FROM EQ-4N BETWEEN 
17W-20W...AND FROM EQ-1N BETWEEN 39W-42W. A LARGE CLUSTER OF 
SCATTERED MODERATE TO STRONG CONVECTION IS ALONG THE COAST OF NE 
BRAZIL FROM 4S-8S BETWEEN 33W-38W. 

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A STATIONARY FRONT IS INLAND OVER THE N GULF 
STATES WITH CONVECTION. A 1019 MB HIGH IS OVER THE NE GULF OF 
MEXICO NEAR 28N85W. FAIR WEATHER AND 5-10 KT ANTICYCLONIC WINDS 
ARE NOTED AROUND THE HIGH. THE REMAINDER OF THE GULF CONTINUES 
TO HAVE 10-15 KT SOUTHERLY RETURN FLOW. A SMALL AREA OF 
SCATTERED MODERATE CONVECTION IS OVER THE BAY OF CAMPECHE FROM 
19N-20N BETWEEN 91W-92W. THE REMAINDER OF THE GULF HAS MAINLY 
FAIR WEATHER. IN THE UPPER LEVELS...ZONAL FLOW WITH STRONG 
SUBSIDENCE IS OVER THE ENTIRE GULF OF MEXICO CONTRIBUTING TO THE 
FAIR WEATHER. EXPECT...CONTINUED FAIR TO PARTLY CLOUDY SKIES 
WITH SE FLOW OVER THE GULF FOR THE NEXT 24 HOURS AS A FRONTAL 
SYSTEM TRAVERSES THE N GULF STATES. 

CARIBBEAN SEA...
FRESH TRADES CONTINUE OVER THE CARIBBEAN SEA WITH STRONGEST 
WINDS ALONG THE COAST OF N COLOMBIA. A LARGE AREA OF SCATTERED 
MODERATE TO STRONG CONVECTION IS INLAND OVER N COLOMBIA FROM 
3N-10N BETWEEN 73W-77W. VERY ISOLATED MODERATE CONVECTION IS 
INLAND OVER PANAMA...COSTA RICA...NICARAGUA...HONDURAS...AND 
BELIZE. ELSEWHERE...RAIN AND SHOWERS ARE OVER THE LEEWARD 
ISLANDS...PUERTO RICO...AND HISPANIOLA N OF 15N AND E OF 74W. IN 
THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS PRODUCING SW-W FLOW 
OVER THE CARIBBEAN. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER 
THE CARIBBEAN. EXPECT...LITTLE CHANGE OVER THE NEXT 24 HOURS.   

ATLANTIC OCEAN...
A LARGE 1025 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 32N45W. A 
SURFACE RIDGE EXTENDS W TO N FLORIDA. SCATTERED SHOWERS ARE N OF 
PUERTO RICO AND THE LEEWARD ISLANDS FROM 19N-22N BETWEEN 
57W-70W. A COLD FRONT IS OVER THE E ATLANTIC N OF THE CANARY 
ISLANDS ALONG 32N14W 29N20W 29N25W. SCATTERED SHOWERS ARE WITHIN 
120 NM S OF THE FRONT. IN THE TROPICS...A SURFACE TROUGH IS E OF 
THE LESSER ANTILLES ALONG 19N54W 13N54W MOVING W. SCATTERED 
SHOWERS ARE WITHIN 90 NM OF THE TROUGH. A CONSIDERABLE AMOUNT OF 
SAHARAN DUST HAS ALSO SPREAD FROM EQ-20N E OF 40W. IN THE UPPER 
LEVELS...AN UPPER LEVEL HIGH IS OVER THE W ATLANTIC NEAR 27N64W. 
A BROAD UPPER LEVEL TROUGH IS FURTHER E BETWEEN 20W-55W. IN THE 
TROPICS...A LARGE UPPER LEVEL HIGH IS CENTERED NEAR 6N36W WITH A 
RIDGE AXIS EXTENDING W TO 8N60W. EXPECT...THE COLD FRONT OVER 
THE E ATLANTIC TO DRIFT E OVER THE NEXT 24 HOURS WITH SHOWERS. 

$$
FORMOSA