000
AXNT20 KNHC 312315
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN MAY 31 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...TROPICAL WAVES...
THE TROPICAL WAVE THAT WAS ALONG 29W IS NO LONGER DISCERNIBLE ON 
THE SURFACE OR IN THE UPPER LEVELS AND WAS DROPPED AT 31/1800 
UTC. 

A TROPICAL WAVE IS ALONG 59W/60W S OF 14N MOVING W NEAR 10 KT. 
WAVE IS FAIRLY WELL DEFINED IN THE LOW CLOUDS BUT THE SOUTH 
PORTION REMAINS OVER SOUTH AMERICA AND WILL CONTINUE TO BE 
HARDER TO DISTINGUISH OVER THE NEXT COUPLE OF DAYS. NO 
ASSOCIATED SHOWER ACTIVITY/CONVECTION. 

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 9N12W 3N22W 1N35W INTO NE BRAZIL 
NEAR 1N50W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE 
N OF 2N TO INLAND OVER SW AFRICA BETWEEN 7W-13W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 180 NM 
EITHER SIDE OF THE ENTIRE ITCZ. 

...DISCUSSION...

GULF OF MEXICO...
THE REMNANT FRONTAL BOUNDARY REMAINS ACROSS THE GULF FROM THE W 
ATLC OVER S FLORIDA JUST N OF THE FLORIDA KEYS ALONG 24N87W 
21N94W. THIS FRONT IS LOSING THE DEW POINT DIFFERENCE THAT HAS 
DEFINED IT AND IS BECOMING A SURFACE TROUGH. SE OF THE FRONT ARE 
SCATTERED SHOWERS/THUNDERSTORMS TO ACROSS W CUBA AND THROUGH THE 
FLORIDA STRAITS WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
WITHIN 60 NM N OF THE FRONT E OF 89W. SCATTERED SHOWERS WITH 
POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF THE 
REMAINDER OF THE FRONTAL BOUNDARY. A WEAK SURFACE HIGH REMAINS 
OVER THE NE GULF ANCHORED BY A 1017 MB HIGH JUST OFFSHORE OF THE 
SE LOUISIANA COAST. A SURFACE TROUGH EXTENDS FROM THE BAY OF 
CAMPECHE INTO THE E PACIFIC REGION OVER THE GULF OF TEHUANTEPEC 
AND IS MERGING WITH THE REMNANT FRONTAL BOUNDARY ABOVE. 
OTHERWISE THE REMAINDER OF THE GULF REMAINS TRANQUIL THIS 
EVENING. 
 
CARIBBEAN SEA...
THE FRONTAL BOUNDARY IN THE W ATLC AND GULF OF MEXICO CONTINUES 
TO BRING SCATTERED SHOWERS/THUNDERSTORMS SOUTHWARD ACROSS MOST 
OF CUBA AND INTO THE NW COASTAL WATERS N OF 21N W OF 79W 
INCLUDING THE YUCATAN CHANNEL. THE ITCZ REMAINS ACROSS PANAMA 
FROM COLOMBIA INTO THE E PACIFIC REGION GENERATING SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION INLAND OVER PANAMA/COSTA 
RICA AND OVER THE SW CARIBBEAN S OF 12N W OF 80W. OTHERWISE THE 
REMAINDER OF THE CARIBBEAN REMAINS TRANQUIL THIS EVENING 
ALTHOUGH MODERATE/STRONG EASTERLY TRADE WINDS REMAIN DUE TO THE 
SURFACE RIDGE ANCHORED OVER THE CENTRAL ATLC BASIN AND THE 
TYPICAL LOWER PRESSURE OVER SOUTH AMERICA. THESE TRADE WINDS 
COULD PRODUCE ISOLATED LOW LEVEL SHOWERS DURING THE NIGHT. THE 
TROPICAL WAVE JUST TO THE E OF THE LESSER ANTILLES WILL BE 
MOVING INTO THE CARIBBEAN LATER TONIGHT AND COULD POSSIBLE BEGIN 
TO GENERATE ISOLATED SHOWERS MAINLY FOR THE WINDWARD ISLANDS.   

ATLANTIC OCEAN...
THE REMNANT FRONTAL BOUNDARY WAS ANALYZED OVER THE W ATLC FROM 
27N77W ACROSS EXTREME S FLORIDA INTO THE GULF OF MEXICO. 
HOWEVER...IT APPEARS THAT IT ACTUALLY EXTENDS FURTHER E FROM A 
1012 MB LOW JUST NE OF BERMUDA ALONG 28N71W THEN INTO THE GULF 
OF MEXICO. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 150 NM OF 
LINE FROM 25N75W INTO THE FLORIDA STRAITS NEAR 24N80W WITH 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE 
FROM 25N75W TO 32N63W. OVER THE E ATLC...A SURFACE TROUGH 
EXTENDS FROM 32N24W ALONG 27N30W TO 28N38W AHEAD OF COLD FRONT 
JUST N OF THE REGION. HOWEVER...THIS SURFACE TROUGH IS EMBEDDED 
WITHIN DRY AIR BUT COULD BE PRODUCING ISOLATED SHOWERS WITHIN 75 
NM OF THE TROUGH AXIS. THE REMAINDER OF THE ATLC IS DOMINATED BY 
A SURFACE RIDGE THAT IS ANCHORED BY A 1024 MB HIGH NEAR 32N50W 
GIVING THE REMAINDER OF THE ATLC BASIN FAIR WEATHER THIS 
EVENING.  

$$
WALLACE