000
AXNT20 KNHC 200611
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 AM EDT FRI MAY 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0545 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 63W/64W TO THE SOUTH OF 
13N. STRONG RAINSHOWERS AND THUNDERSTORMS ARE IN VENEZUELA FROM 
5N TO 9N BETWEEN 64W AND 69W. RAINSHOWERS ARE POSSIBLE TO THE 
SOUTH OF 12N BETWEEN 62W AND 68W.

...THE ITCZ...

FROM SIERRA LEONE NEAR 8N13W TO 3N28W 3N37W...PASSING THROUGH
THE EQUATOR ALONG 50W...AND INTO NORTHEASTERN BRAZIL NEAR 1S52W.
STRONG RAINSHOWERS AND THUNDERSTORMS ARE FROM 4N TO 7N BETWEEN 
9W AND 13W IN THE WATERS OFF THE COAST FROM LIBERIA TO SIERRA 
LEONE. STRONG RAINSHOWERS AND THUNDERSTORMS ALSO ARE FROM 1N TO 
4N BETWEEN 22W AND 28W. ISOLATED MODERATE RAINSHOWERS TO LOCALLY 
STRONG THUNDERSTORMS ARE ELSEWHERE TO THE SOUTH OF 8N BETWEEN
AFRICA AND SOUTH AMERICA.

...DISCUSSION...

THE GULF OF MEXICO...

BROAD UPPER LEVEL CYCLONIC FLOW COVERS THE EXTREME EASTERN GULF 
OF MEXICO TO THE EAST OF 83W. THIS CYCLONIC FLOW IS RELATED TO 
THE LARGER-SCALE CYCLONIC FLOW THAT COVERS THE U.S.A. TO THE 
EAST OF 90W. A SEPARATE UPPER LEVEL CYCLONIC PATTERN IS 
ORGANIZING ITSELF IN THE CENTRAL U.S.A. BROAD SURFACE LOW 
PRESSURE SPANS INTERIOR MEXICO. A NORTHWEST-TO-SOUTHEAST 
ORIENTED TROUGH EXTENDS FROM THE TEXAS BIG BEND TO CENTRAL 
MEXICO AND THE ISTHMUS OF TEHUANTEPEC.

THE CARIBBEAN SEA...

UPPER LEVEL CYCLONIC FLOW WITH A DEEP LAYER TROUGH COVERS THE 
WESTERN TWO-THIRDS OF THE AREA. ONE SURFACE TROUGH IS IN THE 
EAST CENTRAL CARIBBEAN SEA...ALONG 70W PASSING ON TOP OF 
HISPANIOLA...AND FROM 10N TO 20N BETWEEN 56W AND 70W. A SECOND 
SURFACE TROUGH IS BETWEEN HAITI AND JAMAICA. BROKEN MULTILAYERED 
CLOUDS AND POSSIBLE PRECIPITATION ARE FROM 13N TO 20N BETWEEN 
70W AND 77W.

THE ATLANTIC OCEAN...

BROAD UPPER LEVEL CYCLONIC FLOW COVERS THE AREA TO THE NORTH OF 
30N...AND FROM THE AREA OF THE EXTREME EASTERN GULF OF MEXICO 
ACROSS FLORIDA INTO THE ATLANTIC OCEAN FROM CUBA TO THE BAHAMAS 
AND 30N BETWEEN 70W AND 83W...AND COVERING ABOUT THE WESTERN 
TWO-THIRDS OF THE CARIBBEAN SEA. BROAD UPPER LEVEL CYCLONIC FLOW 
COVERS THE ATLANTIC OCEAN TO THE NORTH OF 16N BETWEEN 26W AND 
50W. A SECOND SURFACE TROUGH IS ALONG 60W/61W FROM 26N TO 32N.  
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND RAINSHOWERS AND 
POSSIBLE THUNDERSTORMS ARE WITHIN 360 NM ON EITHER SIDE OF 
31N54W 19N65W. A SURFACE TROUGH PASSES THROUGH 35N48W TO
A 1021 MB LOW PRESSURE CENTER THAT IS NEAR 33N47W. THE TROUGH 
CONTINUES TO 30N47W AND 27N51W. RAINSHOWERS ARE POSSIBLE WITHIN 
60 NM ON EITHER SIDE OF THE TROUGH. A SURFACE RIDGE EXTENDS FROM 
A 1030 MB HIGH PRESSURE CENTER THAT IS NEAR 38N30W TO 14N37W.

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

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