Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 051705
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAY 05 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 7N8W 4N12W 2N19W CROSSING THE EQUATOR 
NEAR 30W AND CONTINUING JUST S OF THE EQUATOR TO 1S50W. 
SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING W FROM THE FAR W 
COAST OF AFRICA ACROSS THE PRIME MERIDIAN TO 3W ENCOMPASSING THE 
SW COAST OF AFRICA TO JUST S OF THE EQUATOR. A SMALLER AREA OF 
SIMILAR CONVECTION IS N OF THE ITCZ WITHIN 75 NM OF LINE FROM 
7N14W TO 4N21W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION ARE FROM 4N TO S OF THE EQUATOR BETWEEN 6W-24W AND S 
OF 2N TO INLAND OVER SOUTH AMERICA BETWEEN 41W-49W. 

...DISCUSSION...

GULF OF MEXICO...
BROAD DEEP LAYERED TROUGH REMAINS OVER THE E U.S. DIPPING S OVER 
THE FLORIDA PENINSULA WITH THE ASSOCIATED FRONTAL BOUNDARY 
INLAND ACROSS THE GULF COAST STATES INTO TEXAS. VERY LITTLE IN 
THE WAY OF PRECIPITATION IS FOUND S OF THE FRONT AS LIGHT SE 
SURFACE FLOW IS EVIDENT FROM SHIP AND BUOY OBSERVATIONS ACROSS 
THE GULF. THESE WINDS ARE LOCATED ON THE W PERIPHERY OF A 
SURFACE RIDGE THAT EXTENDS FROM THE W ATLC ACROSS THE FLORIDA 
PENINSULA TO OVER THE E GULF. OTHERWISE...FAIR WEATHER 
CONDITIONS CONTINUE ACROSS THE GULF TODAY WITH ONLY DEBRIS 
MOISTURE IN THE FORM OF HIGH CLOUDS STREAMING ACROSS THE CENTRAL 
GULF.

CARIBBEAN SEA...
A BROAD UPPER RIDGE DOMINATES THE W CARIBBEAN ANCHORED OVER 
COSTA RICA WHICH IS ADVECTING TROPICAL MOISTURE OVER THE YUCATAN 
AND INTO THE GULF OF HONDURAS TO 75W. THIS MOISTURE IS RESULTANT 
DEBRIS CLOUDINESS FROM SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS OVER CENTRAL AMERICA. A SURFACE TROUGH EXTENDS 
OVER THE E CARIBBEAN FROM 20N66W ACROSS PUERTO RICO TO NEAR 
13N65W. THIS SURFACE TROUGH CONTINUES TO PRODUCE SCATTERED 
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE FAR E 
CARIBBEAN AND LESSER ANTILLES E OF THE AXIS. LIGHT TO MODERATE 
TRADE WINDS COVER THE CARIBBEAN PRIMARILY DUE TO A RELAXED 
PRESSURE GRADIENT LEAVING THE REMAINDER OF THE CARIBBEAN WITH 
SOME ISOLATED LOW LEVEL SHOWERS MOVING WESTWARD IN CONVERGENT 
SURFACE FLOW ACROSS THE BASIN S OF 16N. 

ATLANTIC OCEAN...
THE ATLANTIC BASIN IS DOMINATED BY SURFACE HIGH PRESSURE RIDGE 
ANCHORED NORTH OF THE DISCUSSION AREA. ONE WEAKNESS IN THIS 
SURFACE RIDGE IS LOCATED ACROSS THE W ATLC AS AN UPPER LEVEL LOW 
CENTERED NEAR 25N69W IS PROVIDING SUPPORT FOR A SURFACE TROUGH 
THAT EXTENDS TO JUST N OF THE TURKS AND CAICOS NEAR 23N72W. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OBSERVED E OF THE 
SURFACE TROUGH WITHIN 90 NM OF A LINE FROM 23N66W TO 28N69W. 
THIS ACTIVITY IS LOCATED UNDER A LARGE MID/UPPER LEVEL DIFFLUENT 
ZONE ACROSS THE W ATLC DRAWING TROPICAL MOISTURE FROM THE 
CARIBBEAN N INTO THE UPPER LOW. SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS EXTEND FARTHER TO THE SE ACROSS THE 
LESSER ANTILLES AND TROPICAL ATLC FROM 13N-21N BETWEEN 53W-66W. 
THE SECOND WEAKNESS IN THE ATLC SURFACE RIDGE EXTENDS OVER THE 
E/CENTRAL ATLC AS A SECOND LARGER UPPER LEVEL LOW SPINS NEAR 
29N42W PROVIDING SUPPORT FOR A SURFACE TROUGH THAT EXTENDS 
THROUGH 32N36W ALONG 28N40W TO 23N43W GENERATING SCATTERED 
SHOWERS AND ISOLATED THUNDERSTORMS FROM 28N TO BEYOND 32N 
BETWEEN 33W-43W.

$$
WALLACE