000
AXNT20 KNHC 211137
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 AM EDT SAT MAY 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...TROPICAL WAVES...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 68W/69W TO THE SOUTH
OF 13N. STRONG RAINSHOWERS AND THUNDERSTORMS ARE IN VENEZUELA
FROM 5N TO 10N BETWEEN 65W AND 68W.

...THE ITCZ...

FROM SIERRA LEONE NEAR 8N13W TO 6N20W 2N30W...CROSSING THE 
EQUATOR ALONG 34W...INTO NORTHEASTERN BRAZIL NEAR 4S44W. 
NUMEROUS STRONG RAINSHOWERS AND THUNDERSTORMS ARE FROM 2N
TO THE AFRICA COAST BETWEEN 2E AND 8W...AND FROM 2N TO 7N
BETWEEN 18W AND 22W. SCATTERED MODERATE RAINSHOWERS TO
ISOLATED STRONG THUNDERSTORMS ARE FROM THE EQUATOR TO 9N
BETWEEN 37W AND 60W...AND FROM 2N TO 6S BETWEEN 30W AND 50W.

...DISCUSSION...

THE GULF OF MEXICO...

BROAD UPPER LEVEL CYCLONIC FLOW COVERS THE EXTREME EASTERN GULF 
OF MEXICO TO THE EAST OF 84W. THIS CYCLONIC FLOW IS RELATED TO 
THE LARGER-SCALE CYCLONIC FLOW THAT COVERS THE U.S.A. TO THE 
EAST OF 80W. A SEPARATE UPPER LEVEL CYCLONIC PATTERN IS TO THE 
NORTH OF 31N/32N BETWEEN 95W AND 112W IN THE U.S.A. BROAD 
SURFACE LOW PRESSURE SPANS INTERIOR MEXICO. A NORTHWEST-TO- 
SOUTHEAST ORIENTED SURFACE TROUGH EXTENDS FROM THE TEXAS BIG 
BEND TO CENTRAL MEXICO AND THE ISTHMUS OF TEHUANTEPEC TO 
HONDURAS.

THE CARIBBEAN SEA...

UPPER LEVEL CYCLONIC FLOW WITH A TROUGH COVERS THE WESTERN 
TWO-THIRDS OF THE AREA. RAINSHOWERS AND POSSIBLE THUNDERSTORMS 
ARE ON THE EASTERN SIDE OF THE CYCLONIC FLOW OF THE UPPER LEVEL 
TROUGH...WITHIN 60 TO 120 NM ON EITHER SIDE OF 19N63W 16N66W 
10N74W IN NORTHERN COLOMBIA. THE PRECIPITATION IS ABLE 
TO GROW IN THE ENVIRONMENT OF THE UPPER LEVEL DIFFLUENT FLOW.
A SURFACE TROUGH EXTENDS FROM THE SOUTHWESTERN CORNER OF THE 
DOMINICAN REPUBLIC TO 14N74W TO 11N75W ALONG THE COAST OF 
COLOMBIA. RAINSHOWERS AND THUNDERSTORMS COVER THE AREA FROM 
GUATEMALA INTO HONDURAS...IN BROAD SURFACE LOW PRESSURE.

THE ATLANTIC OCEAN...

BROAD UPPER LEVEL CYCLONIC FLOW COVERS THE AREA TO THE NORTH
OF 30N TO THE WEST OF 65W...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 68W AND 84W...AND 
COVERING ABOUT THE WESTERN TWO-THIRDS OF THE CARIBBEAN SEA.
A COLD FRONT PASSES THROUGH 32N69W TO 29N72W. RAINSHOWERS AND 
THUNDERSTORMS ARE TO THE NORTH OF 30N BETWEEN 60W AND 80W. BROAD 
UPPER LEVEL CYCLONIC FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH 
OF 15N BETWEEN 20W AND 60W. ONE SURFACE TROUGH IS ALONG 29N62W
24N66W 20N68W. A SECOND SURFACE TROUGH CURVES FROM 35N44W TO 
33N47W TO 31N49W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND 
POSSIBLE RAINSHOWERS ARE WITHIN 240 NM ON EITHER SIDE OF 30N57W
22N62W 19N64W. THE PRECIPITATION IS ABLE TO GROW IN THE 
ENVIRONMENT OF THE UPPER LEVEL DIFFLUENT FLOW THAT IS TO THE 
EAST OF THE UPPER LEVEL TROUGH. SURFACE-TO-LOW LEVEL CYCLONIC 
FLOW IN CURRENT VISIBLE SATELLITE IMAGERY COVERS THE AREA FROM 
24N TO 30N BETWEEN 39W AND 44W. BROAD SURFACE ANTICYCLONIC FLOW 
COVERS THE ATLANTIC OCEAN TO THE NORTH OF 15N BETWEEN AFRICA AND 
40W.

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

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MT