000
AXNT20 KNHC 070544
TWDAT 

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

...THE ITCZ...

THE ITCZ AXIS IS ALONG 4N7W 2N20W CROSSING THE EQUATOR NEAR 29W 
AND CONTINUING S OF THE EQUATOR ALONG 1S33W AND INTO NE BRAZIL 
NEAR 1S46W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE 
EQUATOR TO 7N BETWEEN THE PRIME MERIDIAN TO 12W. WIDELY 
SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM THE EQUATOR TO 
7N BETWEEN 12W-23W.

...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 W ATLC ACROSS 
THE FLORIDA PENINSULA INTO THE GULF. ALOFT IN THE MIDDLE TO 
UPPER LEVELS...NW FLOW IS OBSERVED WITH WEAK TROUGHING ACROSS 
THE NE GULF AND NRN FLORIDA. A WEAK SHORTWAVE TROUGH CONTINUES 
TO MOVE ACROSS THE SE CONUS AND TRACK NEWD KEEPING ANY FRONTAL 
BOUNDARIES WELL NORTH OF THE GULF WATERS. THIS EVENING ONLY 
MIDDLE TO HIGH LEVEL CLOUDINESS IS NOTED ON SATELLITE IMAGERY N 
OF 24N E OF 90W...INCLUDING MUCH OF THE STATE OF FLORIDA. 
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...
A BROAD 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...AN UPPER LEVEL TROUGH 
RESIDES E OF 70W WITH ABUNDANT MOISTURE NOTED ON WATER VAPOR 
IMAGERY THAT IS BEING LIFTED IN A LARGE DIFFLUENT ZONE E OF THE 
TROUGH AXIS. THIS ZONE ALONG WITH A SURFACE TROUGH THAT EXTENDS 
ACROSS THE CENTRAL CARIBBEAN FROM 13N71W TO 19N72W IS GENERATING 
SCATTERED SHOWERS 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 1032 MB HIGH LOCATED N OF THE DISCUSSION 
AREA NEAR 35N54W. A WEAKNESS IN THE SURFACE RIDGE...ANALYZED AS 
A SURFACE TROUGH EXTENDS FROM 28N74W TO 23N72W. THIS ALONG WITH 
A BROAD 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 AND POSSIBLE ISOLATED TSTMS 
EXTENDING WITHIN 150 NM OF A LINE FROM THE U.S. VIRGIN ISLANDS 
N-NW TO 27N73W. SCATTERED SHOWERS ARE FARTHER TO THE SE ACROSS 
THE LESSER ANTILLES AND TROPICAL ATLC FROM 15N-22N BETWEEN 
57W-65W. THE SECOND WEAKNESS IN THE ATLC SURFACE RIDGE EXTENDS 
OVER THE E/CENTRAL ATLC AS AN UPPER LEVEL TROUGH WITH AXIS ALONG 
32N29W 22N40W IS PROVIDING SUPPORT FOR A SURFACE TROUGH THAT 
EXTENDS FROM 32N34W TO 26N35W. THIS FEATURE CONTINUES TO 
GRADUALLY WEAKEN AS THE UPPER TROUGH MOVES NEWD. 

$$
HUFFMAN