000
AXNT20 KNHC 071037
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU MAY 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 5N8W 1N20W CROSSING THE EQUATOR NEAR 22W 
AND CONTINUING S OF THE EQUATOR ALONG 2S28W AND INTO NE BRAZIL 
NEAR 3S40W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE 
EQUATOR TO 6N BETWEEN THE PRIME MERIDIAN TO 12W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS UNDER 10-20 KT E TO SE SURFACE FLOW AS A 
SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE FAR W ATLC 
ACROSS THE FLORIDA PENINSULA AND INTO THE GULF. ALOFT IN THE 
MIDDLE TO UPPER LEVELS...A DRY AND SUBSIDENT NORTHWEST FLOW IS 
EVIDENT ON WATER VAPOR IMAGERY WITH WEAK TROUGHING OBSERVED 
ACROSS THE NE GULF AND NRN FLORIDA. A TROUGH CONTINUES TO MOVE 
ACROSS THE ERN CONUS AND TRACK NEWD KEEPING ANY FRONTAL 
BOUNDARIES WELL NORTH OF THE GULF WATERS. ONLY MIDDLE TO HIGH 
LEVEL CLOUDINESS IS NOTED ON SATELLITE IMAGERY N OF 24N E OF 
86W...INCLUDING THE FLORIDA PENINSULA. LOOKING AHEAD...LITTLE 
CHANGE IS EXPECTED IN THE OVERALL PATTERN DURING THE NEXT 24-48 
HOURS WITH FAIR WEATHER CONDITIONS PREVAILING THROUGH SUNDAY.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM COLOMBIA NW ACROSS 
CENTRAL AMERICA AND IS PROVIDING THE WRN CARIBBEAN WITH MAINLY 
WLY ZONAL FLOW AND A DRY SUBSIDENT ATMOSPHERE IN THE MIDDLE AND 
UPPER LEVELS. ACROSS THE ERN CARIBBEAN...A MIDDLE TO UPPER LEVEL 
TROUGH RESIDES E OF 70W WITH ABUNDANT MOISTURE NOTED ON WATER 
VAPOR IMAGERY. THIS MOISTURE IS BEING LIFTED IN A LARGE 
DIFFLUENT ZONE E OF THE TROUGH AXIS AND SUPPORTS A SURFACE 
TROUGH THAT EXTENDS FROM THE N/CENTRAL CARIBBEAN NEAR 16N73W NWD 
ACROSS THE SE BAHAMAS INTO THE W ATLC. SCATTERED SHOWERS 
CONTINUE N OF 14N AND E OF THE SURFACE TROUGH. THIS AREA OF 
PRECIPITATION ACROSS THE NE CARIBBEAN IS FORECAST TO PERSIST 
THROUGH THE WEEKEND UNTIL THE MIDDLE TO UPPER LEVEL TROUGH 
SHIFTS EWD INTO THE CENTRAL ATLC BY LATE SUNDAY. ELSEWHERE... 
MODERATE TO FRESH TRADE WINDS COVER THE CARIBBEAN WITH POSSIBLE 
ISOLATED LOW LEVEL SHOWER ACTIVITY MOVING WESTWARD IN CONVERGENT 
SURFACE FLOW ACROSS THE BASIN.

ATLANTIC OCEAN...
THE W ATLC CONTINUES TO BE DOMINATED BY A SURFACE HIGH PRESSURE 
RIDGE ANCHORED BY A 1031 MB HIGH LOCATED N OF THE DISCUSSION 
AREA NEAR 35N53W. A WEAKNESS IN THE SURFACE RIDGE...ANALYZED AS 
A SURFACE TROUGH EXTENDS FROM 17N73W IN THE N/CENTRAL CARIBBEAN 
SEA ACROSS THE SE BAHAMAS TO 25N73W. THIS ALONG WITH AN UPPER 
LEVEL TROUGH WITH AXIS ALONG 70W IS GENERATING AN AREA OF UPPER 
LEVEL DIFFLUENCE TO THE E OF THE SURFACE TROUGH PRODUCING 
SCATTERED SHOWERS EXTENDING WITHIN 150 NM OF A LINE FROM THE 
MONA PASSAGE N-NW TO 28N74W. SCATTERED SHOWERS ARE FARTHER TO 
THE SE ACROSS THE NE CARIBBEAN SEA...THE LESSER ANTILLES AND 
TROPICAL ATLC FROM 14N-20N BETWEEN 58W-70W. THE REMAINDER OF THE 
CENTRAL AND ERN ATLC IS UNDER THE INFLUENCE OF THE SURFACE RIDGE 
WITH 15 TO 20 KT NE TO ELY TRADES.

$$
HUFFMAN