000
AXNT20 KNHC 201705
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT WED APR 20 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION
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 1715 UTC. 

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W EQ22W 1S30W EQ40W 1N50W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 6N-7S 
BETWEEN 15W-24W. ISOLATED MODERATE CONVECTION IS ALONG THE COAST 
OF BRAZIL FROM 2N-2S BETWEEN 42W-50W. 

...DISCUSSION...

THE GULF OF MEXICO...
10-25 KT SE RETURN FLOW DOMINATES FLORIDA AND THE GULF OF MEXICO 
WITH STRONGEST WINDS OVER THE EASTERN BAY OF CAMPECHE...AND OVER 
THE STRAITS OF FLORIDA. FAIR WEATHER IS NOTED OVER THE ENTIRE 
GULF. IN THE UPPER LEVELS...ZONAL FLOW PREVAILS. AN AREA OF 
UPPER LEVEL MOISTURE AND SCATTERED HIGH CLOUD ARE OVER THE 
FLORIDA PANHANDLE. STRONG SUBSIDENCE IS OVER THE REMAINDER OF 
GULF. EXPECT...SOME AIR MASS SHOWERS AND THUNDERSTORMS OVER S 
MEXICO AND THE BAY OF CAMPECHE S OF 20N...IN THE AFTERNOON AND 
EVENING HOURS. OTHERWISE EXPECT LITTLE CHANGE OVER THE NEXT 24 
HOURS.  

THE CARIBBEAN SEA...
10-20 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH HIGHEST 
WINDS ALONG THE COAST OF N COLOMBIA...THE GULF OF HONDURAS... 
AND THE WINDWARD PASSAGE. SCATTERED SHOWERS ARE OVER COSTA 
RICA...PANAMA...N COLOMBIA...AND VENEZUELA S OF 12N BETWEEN 
65W-84W. SIMILAR SHOWERS ARE OVER THE EASTERN CARIBBEAN E OF 
63W. MOSTLY FAIR WEATHER IS OVER THE REMAINDER OF THE CARIBBEAN. 
IN THE UPPER LEVELS...ZONAL FLOW DOMINATES THE AREA. UPPER LEVEL 
MOISTURE IS OVER S AMERICA... AND THE S CARIBBEAN S OF 10N. 
STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE SEA. EXPECT MORE 
SHOWERS OVER THE SE CARIBBEAN S OF 13N OVER THE NEXT 24 HOURS.   

THE ATLANTIC OCEAN...
SURFACE RIDGING AND FAIR WEATHER DOMINATES THE W ATLANTIC W OF 
70W. A SURFACE TROUGH IS FURTHER E FROM 27N60W TO 19N60W. AN 
EMBEDDED 1012 MB LOW IS ON THE TROUGH AXIS AT 23N60W. ISOLATED 
MODERATE CONVECTION IS N OF THE LOW CENTER FROM 23N-25N BETWEEN 
58W-64W. A TIGHT SURFACE PRESSURE GRADIENT N OF THE LOW IS 
PRODUCING GALE FORCE WINDS WITHIN 300 NM OF THE N QUADRANT. 
ELSEWHERE...A 1030 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC 
NEAR 37N41W. THE TAIL END OF A COLD FRONT IS OVER THE CANARY 
ISLANDS FROM 32N11W TO 29N15W. SCATTERED SHOWERS ARE WITHIN 30 
NM OF THE FRONT. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS 
OVER THE W ATLANTIC NEAR 28N70W SUPPORTING THE E ATLANTIC 
SURFACE SYSTEM. A 90 KT SUBTROPICAL JETSTREAM EXTENDS FROM OVER 
CENTRAL CUBA AT 22N80W TO 23N55W PRODUCING A LOT OF WESTERLY 
VERTICAL WINDSHEAR OVER THE SURFACE LOW. EXPECT OVER THE NEXT 24 
HOURS FOR...THE SURFACE LOW TO MOVE NW TO 24N63W WITH CONTINUED 
CONVECTION AND GALE FORCE WINDS N OF THE CENTER. 

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

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FORMOSA