000
AXNT20 KNHC 181653
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT SAT JUN 18 2011

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...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS OFF THE COAST OF WEST AFRICA FROM 15N22W TO 
10N25W TO 4N26W MOVING W AT 15-20 KT. THIS WAVE HAS A SURGE OF 
MOISTURE FROM 3N-18N...TOGETHER WITH AN INVERTED-V LOW CLOUD 
SIGNATURE. WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE 
ITCZ FROM 4N-8N BETWEEN 23W-32W. SCATTERED SHOWERS ARE WITHIN 
300 NM E OF THE WAVE AXIS.    

TROPICAL WAVE IS E OF THE WINDWARD ISLANDS FROM 17N52W TO 12N55W 
TO 7N57W MOVING W AT 20 KT. THIS WAVE IS WELL DEFINED IN THE 
UPPER LEVEL SATELLITE WINDS...AND HAS A DISTINCT MOISTURE FIELD. 
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE 
FROM 10N-14N BETWEEN 50W-63W. 

TROPICAL WAVE IS OVER THE NW CARIBBEAN AND CENTRAL AMERICA FROM 
23N85W TO 18N86W TO 13N87W MOVING NW AT 15-20 KT. THIS IS A WELL 
DEFINED WAVE WITH A LARGE ASSOCIATED MOISTURE FIELD. CLUSTERS OF 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 
11N-21N BETWEEN 80W-88W.  

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM INLAND AFRICA AT 22N00W TO 
17N4W TO THE COAST AT 16N17W. THE ITCZ IS W OF THE TROPICAL WAVE 
FROM 7N27W TO 5N43W TO SOUTH AMERICA AT 3N51W. CLUSTERS OF 
NUMEROUS STRONG CONVECTION ARE INLAND OVER WEST AFRICA FROM 
10N-14N BETWEEN 4W-13W. ISOLATED MODERATE CONVECTION IF OFF THE 
COAST OF WEST AFRICA FROM 8N-10N BETWEEN 15W-18W. WIDELY 
SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF SOUTH 
AMERICA FROM 1N-4N BETWEEN 47W-53W. 

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE RIDGE AXIS IS OVER THE GULF OF MEXICO ALONG 29N. 5-10 
KT SOUTHERLY WINDS ARE OVER THE E GULF WHILE 10-15 KT SOUTHERLY 
FLOW IS OVER THE W GULF DUE TO A SLIGHTLY TIGHTER SURFACE 
GRADIENT. FAIR WEATHER IS OVER THE GULF EXCEPT OVER THE SE GULF. 
A TROPICAL WAVE IS NOW IN THE YUCATAN CHANNEL PRODUCING 
SCATTERED SHOWERS S OF 24N E OF 87W. IN THE UPPER LEVELS AN 
UPPER LEVEL HIGH IS CENTERED OVER N MEXICO NEAR 25N100W. STRONG 
SUBSIDENCE COVERS THE GULF EXCEPT OVER FLORIDA...CUBA...AND THE 
YUCATAN PENINSULA. EXPECT...MORE THUNDERSTORMS OVER THE STRAITS 
OF FLORIDA...CUBA...THE YUCATAN CHANNEL...AND THE YUCATAN 
PENINSULA OVER THE NEXT 24 HOURS.  

THE CARIBBEAN SEA...
A TROPICAL WAVE IS E OF THE WINDWARD ISLANDS PRODUCING 
CONVECTION. ANOTHER TROPICAL WAVE IS OVER THE NW CARIBBEAN SEA 
AND CENTRAL AMERICA. CONSIDERABLE THUNDERSTORM ACTIVITY IS OVER 
THE W CARIBBEAN W OF 80W. 10-25 KT TRADEWINDS ARE OVER THE 
CARIBBEAN WITH STRONGEST WINDS ALONG THE COAST OF N COLOMBIA. IN 
THE UPPER LEVELS AN UPPER LEVEL HIGH IS CENTERED S OF JAMAICA 
NEAR 15N79W. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER MOST OF 
THE CARIBBEAN AND CENTRAL AMERICA EXCEPT THE LEEWARD ISLANDS. 
EXPECT MORE CONVECTION OVER THE CARIBBEAN AND CENTRAL AMERICA AS 
THE TROPICAL WAVES MOVES W. 

THE ATLANTIC OCEAN...
A 1024 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR 36N59W. A 
COLD FRONT IS ALSO OVER THE W ATLANTIC ALONG 32N49W 28N60W 
27N64W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE FRONT. A 1026 
MB HIGH IS OVER THE E ATLANTIC NEAR 35N26W. A SURFACE RIDGE AXIS 
EXTENDS SW TO 28N49W. EXPECT THE COLD FRONT TO MOVE SLOWLY E 
DURING THE NEXT 24 HOURS WITH SHOWERS.  

F0R ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
FORMOSA