000
AXNT20 KNHC 120521
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE MAY 12 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 5N8W 1N20W CROSSING THE EQUATOR 
NEAR 27W AND CONTINUES TO NE BRAZIL NEAR 3S40W. SCATTERED 
MODERATE CONVECTION IS FROM 1N-3N BETWEEN 31W-34W. WIDELY 
SCATTERED MODERATE CONVECTION IS FROM 1S-4S BETWEEN 20W-25W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A 1015 MB LOW IS CENTERED OVER N FLORIDA NEAR 
30N82W. A COLD FRONT EXTENDS W FROM THE LOW TO THE FLORIDA 
PANHANDLE TO 31N87W. SCATTERED MODERATE CONVECTION IS INLAND IN 
THE VICINITY OF PENSACOLA FLORIDA FROM 30N-31N BETWEEN 86W-87W.  
A 1019 MB HIGH IS OVER THE NE GULF OF MEXICO NEAR 28N87W. 
5-10 KT ANTICYCLONIC WINDS ARE NOTED AROUND THE HIGH. THE 
REMAINDER OF THE GULF CONTINUES TO HAVE 10-15 KT SE RETURN FLOW. 
FAIR TO PARTLY CLOUDY WEATHER DOMINATES THE ENTIRE GULF OF 
MEXICO. IN THE UPPER LEVELS...ZONAL FLOW IS OVER THE GULF OF 
MEXICO. CONSIDERABLE UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS 
ARE OVER THE SURROUNDING LAND MASSES FROM MEXICO TO LOUISIANA TO 
FLORIDA WHILE STRONG SUBSIDENCE REMAINS OVER THE GULF. 
EXPECT...THE SURFACE LOW AND COLD FRONT TO MOVE TO CENTRAL 
FLORIDA OVER THE NEXT 24 HOURS WITH CONVECTION. ALSO EXPECT 
CONTINUED SE SURFACE FLOW OVER THE GULF OF MEXICO. 

CARIBBEAN SEA...
FRESH TRADES CONTINUE OVER THE CARIBBEAN SEA WITH STRONGEST 
WINDS ALONG THE COAST OF N COLOMBIA. AN AREA OF SCATTERED 
MODERATE CONVECTION IS ALONG THE COASTS OF PANAMA AND COSTA RICA 
FROM 9N-11N BETWEEN 79W-84W. WIDELY SCATTERED MODERATE 
CONVECTION IS INLAND OVER EL SALVADOR...HONDURAS...AND GUATEMALA 
FROM 13N-16N BETWEEN 88W-90W. 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...A SURFACE TROUGH TO 
TRAVERSE THE LEEWARD ISLANDS OVER THE NEXT 24 HOURS WITH 
SHOWERS. 

ATLANTIC OCEAN...
PREFRONTAL ACTIVITY IS PRODUCING SCATTERED MODERATE CONVECTION 
ALONG THE COAST OF N FLORIDA FROM 28N-31N BETWEEN 80W-81W...AND 
FROM 30N-32N BETWEEN 75W-80W. A LARGE 1027 MB HIGH IS OVER THE 
CENTRAL ATLANTIC NEAR 31N40W PRODUCING MAINLY FAIR WEATHER. A 
SURFACE RIDGE EXTENDS W TO CENTRAL FLORIDA. A SURFACE TROUGH IS 
JUST E OF THE LEEWARD ISLANDS ALONG 61W FROM 15N-20N. SCATTERED 
SHOWERS ARE WITHIN 180 NM OF THE TROUGH AXIS. IN THE UPPER 
LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W ATLANTIC N OF 20N 
BETWEEN 55W-65W. AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL 
ATLANTIC NEAR 24N42W. IN THE TROPICS...A LARGE UPPER LEVEL HIGH 
IS CENTERED NEAR 4N35W WITH A RIDGE AXIS EXTENDING W TO 4N55W. 
EXPECT...THE COLD FRONT OVER N FLORIDA TO DRIFT SE OVER THE NEXT 
24 HOURS WITH CONVECTION. 

$$
FORMOSA