000 AXNT20 KNHC 102342 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURES... TROPICAL STORM SEAN IS CENTERED NEAR 31.0N 69.0W AT 11/0000 UTC OR ABOUT 230 NM WSW OF BERMUDA MOVING ENE AT 11 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. SEAN LIES TO THE E OF AN AREA OF STRONG DRY AIR ALOFT WHICH IS INHIBITING ANY DEEP CONVECTION ON THE W SIDE OF THE SYSTEM. SCATTERED MODERATE CONVECTION IS TO THE E OF THE CENTER FROM 28N-32N BETWEEN 65W-69W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF GUINEA-BISSAU NEAR 12N16W CONTINUING SW TO 8N18W. THE ITCZ CONTINUES FROM 8N18W ALONG 6N30W 7N40W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ REGION FROM 10N45W 4N46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 4N-8N BETWEEN 19W-27W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 4N-11N BETWEEN 29W-44W. SIMILAR ACTIVITY IS W OF THE SURFACE TROUGH FROM 9N-12N BETWEEN 48W-55W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT CONTINUES TO PUSH THROUGH THE GULF OF MEXICO THIS EVENING EXTENDING FROM NE FLORIDA NEAR 31N81W CONTINUING SW TO THE YUCATAN PENINSULA AND BAY OF CAMPECHE ALONG 23N87W 18N93W. OVERCAST SKIES WITH ISOLATED SHOWERS EXTEND 400 NM BEHIND THE FRONT ALONG WITH STRONG NLY WINDS. GALE FORCE WINDS ARE NOTED IN THE SW GULF S OF 23N W OF 94W. THESE GALE FORCE WINDS ARE EXPECTED TO LAST THROUGH TOMORROW AFTERNOON. ALOFT...A LONGWAVE UPPER TROUGH EXTENDS FROM THE GREAT LAKES REGION TO NRN MEXICO SUPPORTING THE COLD FRONT. STRONG DRY AIR AND SUBSIDENCE ARE AROUND THE BASE AND WRN SIDE OF THE UPPER TROUGH LEAVING THE FAR NW CORNER OF THE GULF UNDER CLEAR SKIES. AS THE FRONT CONTINUES TO PUSH SE THIS DRY AIR WILL EXTEND FARTHER ACROSS THE BASIN AS A SURFACE RIDGE BUILDS OVER THE NRN GULF. CARIBBEAN SEA... A STRONG UPPER RIDGE COVERS THE WRN CARIBBEAN CENTERED E OF NICARAGUA NEAR 13N83W. DRY AIR ALOFT ACCOMPANIES THE UPPER RIDGE WHICH IS MAINTAINING FAIR SURFACE CONDITIONS BESIDES A FEW ISOLATED SHOWERS E OF THE YUCATAN PENINSULA AND ACROSS HONDURAS. CLUSTERS OF SHOWERS/THUNDERSTORMS ARE IN THE FAR SW CARIBBEAN S OF 13N W INCLUDING PORTIONS OF COSTA RICA AND PANAMA. THIS ACTIVITY IS INFLUENCE BY THE MONSOON TROUGH THAT EXTENDS ACROSS COSTA RICA TO NRN COLOMBIA. THE ERN HALF OF THE BASIN IS COVERED BY A BROAD UPPER TROUGH WITH AXIS ALONG 67W. A SURFACE TROUGH LIES UNDERNEATH ALONG 18N69W TO 13N72W. SCATTERED SHOWERS/THUNDERSTORMS ARE E OF THE SURFACE TROUGH FROM 14N-20N BETWEEN 65W-69W ACROSS PORTIONS OF PUERTO RICO AND HISPANIOLA. EXPECT THE COLD FRONT IN THE GULF OF MEXICO TO REACH THE NW CARIBBEAN WITHIN THE NEXT 12-18 HOURS BRINGING SHOWERS AND STRONG WINDS BEHIND IT. ATLANTIC OCEAN... TROPICAL STORM SEAN DOMINATES THE WRN ATLC. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A COLD FRONT CURRENTLY ACROSS THE GULF OF MEXICO WILL ENTER THE ATLC BASIN OVER THE NEXT COUPLE OF HOURS AND WILL EVENTUALLY ABSORB T.S. SEAN OVER THE NEXT DAY OR SO. ALOFT...AN UPPER LEVEL RIDGE EXTENDS TO THE W OF SEAN ALONG WITH DRY AIR. A SHORTWAVE UPPER TROUGH IS THE E EXTENDING FROM 36N72W TO 20N61W WHICH IS SUPPORTING A CLUSTER OF SHOWERS/THUNDERSTORMS FROM 24N-27N BETWEEN 60W-63W. THIS UPPER TROUGH IS ALSO SUPPORTING SCATTERED SHOWERS N OF 28N BETWEEN 52W-59W. FARTHER E...AN UPPER LEVEL RIDGE IS ALONG 52W SUPPORTING A SURFACE RIDGE TO THE N ANCHORED BY A 1028 MB HIGH NEAR 42N51W. A STATIONARY FRONT BISECTS THE SURFACE RIDGE EXTENDING FROM A WEAK 1014 MB LOW OVER NW AFRICA NEAR 32N8N WITH FRONT EXTENDING WWD ALONG 27N20W 27N36W 28N52W. SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT. A SMALL AREA OF HIGHER PRESSURE REMAINS S OF THE FRONT NEAR A 1018 MB HIGH AT 23N43W. THE STATIONARY BOUNDARY IS SUPPORTED BY A BROAD UPPER TROUGH COVERING THE ERN ATLC N OF 25N. A CUT-OFF UPPER LOW IS TO THE S NEAR 18N38W SUPPORTING AN AREA OF CLOUDINESS AND POSSIBLE SHOWERS FROM 13N-20N. EXPECT THE STATIONARY BOUNDARY TO BEGIN TO WEAKEN OVER THE NEXT 24-48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON