TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST MON NOV 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2335 UTC.

...SPECIAL FEATURE...
TROPICAL STORM SEAN IS CENTERED NEAR 27.8N 69.8W...OR ABOUT 430 
MI...695 KM SW OF BERMUDA. THE ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 999 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 45 KTS 
WITH GUSTS TO 55 KTS. SEAN IS CURRENTLY STATIONARY. FOR MORE 
INFORMATION SEE THE FORECAST/ADVISORY UNDER THE AWIPS/WMO 
HEADERS MIATCMAT4/WTNT24 KNHC...AND THE PUBLIC ADVISORY LISTED 
UNDER THE AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC. SEAN IS 
DOMINATING THE WRN ATLC PRODUCING A LARGE CYCLONIC WIND FIELD. 
SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE FROM 25N-32N 
BETWEEN 65W-73W.

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

THE MONSOON TROUGH REMAINS INLAND ACROSS WEST AFRICA. THE ITCZ 
EXTENDS ALONG 8N20W 7N30W 5N40W TO 7N52W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS WITHIN 140 NM ON EITHER SIDE OF 
THE AXIS. 

...DISCUSSION...

THE GULF OF MEXICO...
A PRE-FRONTAL BOUNDARY IS ENTERING THE NW GULF WATERS...OFF THE 
COAST OF TEXAS. DOPPLER RADAR IMAGERY INDICATES THE LINE 
COMPOSED OF MODERATE TO HEAVY SHOWERS ALONG GALVESTON BAY TO 
NEAR 26N95W. THE SEVERE WEATHER IS FOCUSED INLAND ACROSS ERN 
TEXAS. THE COLD FRONT BEHIND THE PRE FRONTAL CONVECTION IS STILL 
MOVING ACROSS ESE TEXAS. THIS FRONT IS EXPECTED TO ENTER THE NW 
GULF TONIGHT ALONG WITH GUSTY NORTHERLY WINDS UP TO 20 KT BEHIND 
IT. OTHERWISE...MOSTLY FAIR WEATHER WITH A FEW ISOLATED WEAK 
SHOWERS IS CURRENTLY OBSERVED ACROSS THE AREA. SSE SURFACE FLOW 
10-20 KT IF OBSERVED IN THE WRN GULF W OF 90W. THIS FLOW WILL 
CONTINUE TO INCREASE IN RESPONSE OF THE COMING FRONT.

THE CARIBBEAN SEA...
DRY AIR ALOFT AND STRONG SUBSIDENCE COVERS A GREAT PART OF THE 
CARIBBEAN SEA THIS EVENING...SUPPRESSING DEEP CONVECTION ACROSS 
MOST OF THE BASIN. AT LOWER LEVELS TPW PRODUCT DISPLAYS MODERATE 
TO HIGH MOISTURE VALUES PRESENT OVER THE SW...CENTRAL...AND ERN 
BASIN. CONSEQUENTLY...LAST VISIBLE PICTURES OF THE DAY REVEALED 
SCATTERED WEAK SHOWERS OVER THE NW AND CENTRAL BASINS. A SMALL 
CLUSTER OF SHOWERS ARE OVER THE ERN BASIN...IN THE VICINITY OF A 
SURFACE TROUGH ANALYZED FROM 17N63W TO 12N65W. THIS TROUGH IS 
EXPECTED TO CONTINUE TO SLOWLY MOVE WESTWARD WITH INCREASING 
CONVECTION OVER THE NEXT 24 HOURS. SCATTERED SHOWERS AND 
THUNDERSTORMS ARE ALSO IN THE SW CARIBBEAN S OF 12N W OF 73W... 
ASSOCIATED TO THE MONSOON TROUGH EXTENDING ACROSS COSTA RICA TO 
NRN COLOMBIA. SHORT RANGE MODEL DATA SUGGEST THIS AREA OF 
CONVECTION WILL LINGER OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
TROPICAL STORM SEAN CONTINUES TO IMPACT THE WRN ATLC WITH 
SCATTERED STRONG CONVECTION AROUND THE CENTER AND A GUSTY 
CYCLONIC WIND FIELD W OF 62W. FOR MORE INFORMATION SEE SPECIAL 
FEATURE ABOVE. WATER VAPOR IMAGERY SHOWS BROAD CYCLONIC FLOW 
ALOFT SURROUNDING T.S. SEAN...GENERATING SEVERAL SHORTWAVES 
SUPPORTING A SURFACE TROUGH EXTENDING FROM N OF PUERTO RICO NEAR 
19N66W TO 24N63W. MOST OF THE CONVECTION ASSOCIATED TO THIS 
SYSTEM IS WELL TO THE EAST WITH SCATTERED SHOWERS/THUNDERSTORMS 
N OF 18N BETWEEN 53W-63W. AN UPPER LEVEL TROUGH IS IN THE ENE 
ATLC IS SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA 
NEAR 32N20W TO 27N30W BECOMING STATIONARY FROM THIS POINT ALONG 
25N40W 27N50W TO 30N55W. SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE FRONTAL 
SYSTEM.