000 AXNT20 KNHC 101754 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EDT THU NOV 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL STORM SEAN IS CENTERED NEAR 30.5N 70.0W AT 10/1800 UTC OR ABOUT 290 NM W-SW OF BERMUDA MOVING NE AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 983 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. SMALL UPPER RIDGE ASSOCIATED WITH SEAN IS WITHIN 120/150 NM OF 30N70W. SCATTERED MODERATE CONVECTION IS FROM 29N-31N BETWEEN 69W-72W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 12N16W TO 9N19W. THE ITCZ AXIS EXTENDS FROM 9N19W ALONG 6N32W TO 7N43W. A SURFACE TROUGH EXTENDS FROM 11N43W TO 4N45W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-10N BETWEEN 15W-34W...FROM 4N-12N BETWEEN 34W-47W AND FROM 9N-13N BETWEEN 48W-54W. ...DISCUSSION... GULF OF MEXICO... A RE-ENFORCING UPPER TROUGH IS PUSHING ACROSS THE MISSISSIPPI VALLEY AND IS ABSORBING THE SHORTWAVE UPPER TROUGH MOVING ACROSS THE GREAT LAKES REGION THAT IS SUPPORTING A COLD FRONT THAT ENTERS THE GULF AT 10/1500 UTC ACROSS E GEORGIA AND FLORIDA NEAR 30N83W EXTENDING ALONG 25N87W TO 20N93W THEN S TO OVER S MEXICO NEAR 18N93W. THE REMNANTS OF A STATIONARY BOUNDARY REMAIN OVER MEXICO W OF THE ISTHMUS OF TEHUANTEPEC. MOST OF THE ENERGY ASSOCIATED WITH THE UPPER TROUGH IS LOCATED WELL N OF THE GULF CONSEQUENTLY THE FRONT LACKS ANY SIGNIFICANT DEEP CONVECTION. HOWEVER...SCATTERED SHOWERS ARE W OF THE FRONT AND E OF A LINE FROM NEAR LAKE CHARLES LOUISIANA TO JUST N OF BROWNSVILLE TEXAS. SKIES ARE CLEARING W OF THAT LINE. A SURFACE RIDGE IS BUILDING W OF THE FRONT ANCHORED BY A 1035 MB HIGH OVER W TEXAS. THIS IS LEAVING THE SE GULF UNDER MOSTLY CLEAR SKIES FOR THE MOMENT. CONDITIONS WILL BE CHANGING LATER THIS AFTERNOON INTO THE EVENING AS THE FRONT APPROACHES. THE COLD FRONT WILL REACH FROM SW FLORIDA TO THE NE YUCATAN PENINSULA TONIGHT MOVING INTO THE CARIBBEAN AND W ATLC BY FRI MORNING. SURFACE RIDGE WILL CONTINUE TO BUILD BEHIND THE FRONT WITH WINDS AND SEAS CONTINUING TO DIMINISH AND SUBSIDE THROUGH MON. CARIBBEAN SEA... AN UPPER RIDGE COVERS THE CARIBBEAN W OF 75W ANCHORED OVER NICARAGUA COAST NEAR 13N84W WITH WATER VAPOR IMAGERY INDICATING DRY STABLE AIR AND STRONG SUBSIDENCE OVER THE BASIN N OF 13N W OF 70W. A BROAD UPPER TROUGH OVER THE W ATLC EXTENDS S OVER THE REMAINDER OF THE CARIBBEAN E OF 75W WITH A SURFACE TROUGH EXTENDING FROM THE E TIP OF THE DOMINICAN REPUBLIC ALONG 16N70W TO 13N71W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM E OF THE TROUGH N OF 16N INCLUDING PUERTO RICO AND FROM 12N-17N BETWEEN 61W-65W INCLUDING THE LESSER ANTILLES. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 10N74W ALONG 11N77W INTO THE E PACIFIC REGION ACROSS PANAMA/COSTA RICA NEAR 9N83W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N BETWEEN 75W-82W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH FAIR CONDITIONS THIS AFTERNOON. THE COLD FRONT WILL MOVE INTO THE NW CARIBBEAN FRI MORNING STALLING AND WEAKENING FROM E CUBA TO THE GULF OF HONDURAS SAT MORNING. ATLANTIC OCEAN... THE PRIMARY CONCERN FOR BERMUDA IS TROPICAL STORM SEAN THAT IS FORECASTED TO MOVE N OF THE AREA THIS EVENING WHILE STRENGTHENING THEN PASSING NW OF THE ISLANDS BY FRI MORNING. AN UPPER RIDGE AXIS EXTENDS FROM THE CARIBBEAN ACROSS CUBA NEAR 22N79W TO BEYOND 32N76W WITH DRY STABLE AIR WITHIN 200 NM EITHER SIDE OF THE RIDGE AXIS. THIS DRY AIR IS BEGINNING TO BE DRAWN INTO TROPICAL STORM SEAN. A BROAD UPPER TROUGH COVERS MOST OF THE W ATLC INTO THE CENTRAL ATLC BETWEEN 58W-73W AND S TO OVER THE E CARIBBEAN. TROPICAL STORM SEAN IS EMBEDDED WITHIN THIS BROAD FEATURE. CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ARE BEING DRAWN E OF SEAN FROM 18N-31N BETWEEN 55W-68W WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS FROM 18N-20N BETWEEN 64W-67W INCLUDING THE PUERTO RICO...THE VIRGIN ISLANDS...AND THE MONA PASSAGE. A VERY BROAD UPPER TROUGH COVERS THE E ATLC INTO THE CENTRAL ATLC N OF 32N BUT IS EXTENDING A REMNANT COLD FRONT FROM A WEAK 1016 MB LOW OVER MOROCCO NEAR 31N8W TO THE CANARY ISLANDS NEAR 28N13W WHERE IT CONTINUES AS A STATIONARY FRONT ALONG 27N27W 26N40W TO 28N53W WITH SCATTERED SHOWERS POSSIBLE WITHIN 120 NM EITHER SIDE OF THE FRONT. AN UPPER LOW IS IN THE TROPICS NEAR 17N38W WHICH IS AMPLIFYING THE UPPER RIDGE TO THE E DRAWING TROPICAL MOISTURE N FROM THE ITCZ WITH SCATTERED SHOWERS FROM 12N-20N BETWEEN 31W-37W. THE GULF OF MEXICO COLD FRONT WILL MOVE INTO THE NW PORTION TONIGHT QUICKLY REACHING FROM 31N72W TO THE STRAITS OF FLORIDA FRI MORNING THEN INTO THE CENTRAL ATLC SAT WHERE IT WILL DISSIPATE. SURFACE RIDGE WILL BUILD BEHIND THE FRONT THIS WEEKEND INTO EARLY NEXT WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW