000
AXNT20 KNHC 081038
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 AM EDT SUN MAY 08 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.

...ITCZ...

ITCZ AXIS IS ANALYZED FROM 6N9W 5N18W 3N24W S OF THE EQUATOR 
NEAR 29W CONTINUING SOUTH OF THE EQUATOR TO INLAND OVER SOUTH 
AMERICA. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 180 NM N 
OF THE ITCZ BETWEEN 14W-26W...WITHIN 180 NM S OF THE ITCZ 
BETWEEN 17W-21W...AND WITHIN 90 NM ALONG THE COAST OF LIBERIA 
AND THE IVORY COAST S OF 7N W OF 5W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF A LINE FROM 1N30W TO 2N37W. 
CLUSTERS OF SIMILAR CONVECTION ARE FROM 2N TO THE COAST OF SW 
AFRICA E OF 4W ACROSS THE PRIME MERIDIAN AND WITHIN 200 NM S OF 
THE ITCZ BETWEEN 11W-17W. 

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE EXTENDING FROM THE W CARIBBEAN IS GIVING THE 
GULF OF MEXICO NEAR WESTERLY ZONAL FLOW ALOFT. AN UPPER TROUGH 
IN THE W ATLC HAS BEEN TRAILING A QUASI-STATIONARY FRONTAL 
BOUNDARY ACROSS S FLORIDA AT 08/0900 UTC DISSIPATES JUST E OF 
THE BAHAMA ISLANDS. POSSIBLE ISOLATED SHOWERS REMAIN OVER FAR SE 
FLORIDA S OF FORT LAUDERDALE. WATER VAPOR IMAGERY INDICATES SOME 
DRY STABLE AIR ALOFT GIVING MOST OF THE GULF CLEAR SKIES THIS 
MORNING WITH SOME LINGERING LOW LEVEL MOISTURE REMAINING OVER 
THE N/CENTRAL GULF WITH POSSIBLE ISOLATED SHOWERS WITHIN 60 NM 
OF LINE FROM 25N86W TO 29N89W. A WEAK SURFACE RIDGE IS REMAINS 
OVER THE NE GULF WITH A 1016 MB HIGH OFF TAMPA FLORIDA NEAR 
28N84W AT 08/0900 UTC. SE TO S RETURN FLOW AROUND THE SURFACE 
RIDGE REMAINS OVER ALL BUT THE FAR S GULF. THE SURFACE RIDGE 
WILL OVER THE NE GULF AND WILL MEANDER THERE THROUGH THU. FRESH 
S RETURN FLOW WILL LIE OVER THE W GULF TODAY THROUGH TUE AND 
OCCASIONALLY BECOME STRONG IN THE SW GULF WED AND THU.

CARIBBEAN SEA...
BROAD UPPER RIDGE EXTENDS FROM THE TROPICAL ATLC ACROSS THE 
CARIBBEAN BASIN ACROSS NE VENEZUELA AND THE ABC ISLANDS TO THE 
GULF OF HONDURAS. WATER VAPOR IMAGERY SHOWS DRY STABLE AIR OVER 
THE N CARIBBEAN N OF 15N. A BAND OF LINGERING LOW LEVEL MOISTURE 
REMAINS E TO W ACROSS THE CARIBBEAN GENERATING PATCHES OF 
SCATTERED SHOWERS LEAVING THE SE AND NW CARIBBEAN UNDER MOSTLY 
CLEAR SKIES THIS MORNING. FRESH NE TO E TRADE WINDS WILL 
CONTINUE OVER THE CENTRAL AND SW CARIBBEAN AND ARE EXPECTED TO 
DIMINISH TUE. LIGHT TO MODERATE E TRADE WINDS PREVAILING 
ELSEWHERE THROUGH THU EXCEPT BECOMING FRESH IN THE GULF OF 
HONDURAS BEGINNING LATE TUE AND THE SE CARIBBEAN LATE THU.

ATLANTIC OCEAN...
AN UPPER TROUGH IS OVER THE W ATLC N OF 26N W OF 60W TO JUST E 
OF THE FLORIDA PENINSULA SUPPORTING A COLD FRONT THAT AT 08/0900 
UTC ENTERS THE DISCUSSION AREA NEAR BERMUDA ALONG 29N67W TO 
27N74W WHERE IT BECOMES STATIONARY TO JUST E OF GREAT ABACO 
ISLAND OF THE BAHAMAS. SCATTERED SHOWERS/THUNDERSTORMS ARE 
WITHIN 75 NM E OF THE FRONT N OF 28N WITH SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 30 NM E OF THE REMAINDER 
OF THE FRONT. A 1017 MB HIGH IS S OF THE FRONT NEAR ANDROS 
ISLAND OF THE BAHAMAS. NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES 
THE REMAINDER OF THE ATLC BETWEEN 20N-30N. A WEAKENING 1016 MB 
HIGH IS LOCATED NEAR 25N62W. AN UPPER LOW IS N OF 30N NEAR 
34N42W SUPPORTING A COMPLEX SERIES OF SURFACE LOWS/TROUGHS. A 
1007 MB LOW IS IN THE DISCUSSION AREA NEAR 30N43W WITH A SURFACE 
TROUGH EXTENDING SW TO 27N47W...A 1005 MB LOW IS N OF THE AREA 
NEAR 34N42W WITH A SURFACE TROUGH EXTENDING S ALONG 30N41W TO 
25N47W AND A DOMINATE SURFACE TROUGH EXTENDING THROUGH 32N36W 
ALONG 25N35W TO 18N43W. SCATTERED SHOWERS ARE WITHIN 120/150 NM 
E OF THE DOMINATE SURFACE TROUGH. A SURFACE RIDGE DOMINATES THE 
REMAINDER OF THE E ATLC ANCHORED BY A 1020 MB HIGH NEAR 32N23W. 
THE W ATLC FRONT WILL REACH ABOUT 250 NM E OF THE BERMUDA TO 
ALONG 27N BY TONIGHT THEN DISSIPATE. A SECOND COLD FRONT WILL 
SWEEP SE ACROSS THE AREA MON AND TUE. LOW PRESSURE WILL APPROACH 
BERMUDA FROM THE N WED AND THU INCREASING THE PRESSURE GRADIENT 
AND WINDS BETWEEN IT AND SURFACE RIDGE OVER THE NE GULF OF 
MEXICO.

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

$$
PAW