000
AXNT20 KNHC 061711
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED MAY 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 7N7W 3N16W 2N25W CROSSING THE EQUATOR 
NEAR 32W AND CONTINUING S OF THE EQUATOR ALONG 1S37W INTO NE 
BRAZIL NEAR 1S47W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 
THE COAST OF SW AFRICA TO THE EQUATOR BETWEEN 2W-10W. SCATTERED 
MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED STRONG CONVECTION 
COVERS THE AREA FROM THE EQUATOR TO 9N BETWEEN 10W-20W. CLUSTERS 
OF SCATTERED MODERATE CONVECTION ARE ELSEWHERE FROM THE EQUATOR 
TO 4N BETWEEN 23W-40W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS RATHER TRANQUIL THIS AFTERNOON AS SE TO S 
SURFACE FLOW DOMINATES ACROSS THE ENTIRE REGION S OF A FRONTAL 
BOUNDARY LOCATED WELL NORTH OF THE GULF COAST ACROSS PORTIONS OF 
THE SE U.S. AND E TEXAS. AN UPPER LEVEL SHORTWAVE TROUGH MOVING 
OVER THE LOWER MISSISSIPPI VALLEY CONTINUES TO SUPPORT THE 
FRONTAL BOUNDARY WITH A PUSH OF MID/HIGH LEVEL CLOUDINESS 
STREAMING OVER THE FAR NW GULF WATERS OFF THE COAST OF LOUISIANA 
AND TEXAS. THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN WELL NORTH 
OF THE GULF COAST AS A SURFACE RIDGE ANCHORED IN THE W ATLC 
HOLDS IN PLACE ACROSS THE FLORIDA PENINSULA AND GULF WATERS 
THROUGH THE WEEKEND. LITTLE CHANGE IS EXPECTED IN THE OVERALL 
PATTERN DURING THE NEXT 24-48 HOURS WITH FAIR WEATHER CONDITIONS 
PREVAILING THROUGH EARLY SUNDAY.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE DOMINATES THE W CARIBBEAN ANCHORED 
OVER NICARAGUA WHICH IS ADVECTING TROPICAL MOISTURE INTO THE 
GULF OF HONDURAS AND W CARIBBEAN TO 76W. THIS MOISTURE IS 
RESULTING IN HIGH DEBRIS CLOUDS FROM 16N-20N BETWEEN 76W-87W 
INCLUDING JAMAICA. ALOFT ACROSS THE E CARIBBEAN...UPPER LEVEL 
TROUGH EXTENDS FROM THE W ATLC ACROSS HISPANIOLA TO NEAR 15N68W 
WITH A WEAK SURFACE TROUGH EXTENDING ACROSS HISPANIOLA NEAR 
20N71W TO 15N69W. THE EASTERLY TRADES ALONG WITH THE UPPER LEVEL 
TROUGHING IS GENERATING SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS N OF 15N E OF THE SURFACE TROUGH TO OVER THE 
LEEWARD/VIRGIN ISLANDS AND PUERTO RICO. ELSEWHERE...LIGHT TO 
MODERATE TRADE WINDS COVER THE CARIBBEAN PRIMARILY DUE TO A 
RELAXED PRESSURE GRADIENT LEAVING THE REMAINDER OF THE CARIBBEAN 
WITH POSSIBLE ISOLATED LOW LEVEL SHOWER ACTIVITY MOVING WESTWARD 
IN CONVERGENT SURFACE FLOW ACROSS THE BASIN. THIS FLOW IS ALSO 
BANKING LOW LEVEL CLOUDS WITH SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS INLAND AND WITHIN 90 NM ALONG THE COAST 
OF CENTRAL AMERICA S OF 13N W OF 81W.  

ATLANTIC OCEAN...
THE W ATLC CONTINUES TO BE DOMINATED BY A SURFACE HIGH PRESSURE 
RIDGE ANCHORED BY A 1033 MB HIGH LOCATED N OF THE DISCUSSION 
AREA NEAR 36N54W. A WEAKNESS IN THE SURFACE RIDGE...ANALYZED AS 
A SURFACE TROUGH EXTENDS FROM 27N72W OVER THE EASTERN MOST TURKS 
AND CAICOS INTO THE CARIBBEAN ACROSS HISPANIOLA NEAR 20N71W. 
THIS SURFACE FEATURE IS CONTINUING TO LOSE UPPER LEVEL SUPPORT 
FROM A BROAD UPPER TROUGH THAT EXTENDS THROUGH 32N74W S TO 
26N74W INTO THE NE CARIBBEAN ACROSS HISPANIOLA AND IS EMBEDDED 
WITHIN A SUBSIDENT DRY AIRMASS BUT IS GENERATING AN AREA OF 
UPPER LEVEL DIFFLUENCE FURTHER TO THE E WHICH IS PRODUCING 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 
150/200 NM OF A LINE FROM THE U.S. VIRGIN ISLANDS NNW TO 32N69W. 
SCATTERED SHOWERS ARE FARTHER TO THE SE ACROSS THE LESSER 
ANTILLES AND TROPICAL ATLC FROM 14N-20N BETWEEN 57W-68W. THE 
SECOND WEAKNESS IN THE ATLC SURFACE RIDGE EXTENDS OVER THE 
E/CENTRAL ATLC AS AN ELONGATED NE/SW UPPER LEVEL LOW CENTERED 
NEAR 29N35W PROVIDING SUPPORT FOR A SURFACE TROUGH THAT EXTENDS 
FROM 32N35W SW TO 26N42W GENERATING SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS FROM 28N-32N BETWEEN 32W AND THE 
SURFACE TROUGH. THE REMAINDER OF THE E AND CENTRAL ATLC IS UNDER 
FAIR WEATHER CONDITIONS. 

$$
WALLACE