000 AGXX40 KNHC 200932 AAA MIMATS MARINE WEATHER DISCUSSION...UPDATED NWS NATIONAL HURRICANE CENTER MIAMI FL 530 AM EDT THU OCT 20 2011 UPDATED WARNINGS MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE COLD FRONT OF THE PAST FEW DAYS CLEARED THE GULF YESTERDAY EVENING...AND CURRENTLY EXTENDS FROM WESTERN CUBA SW TO BELIZE AND GUATEMALA. CONTINENTAL HIGH PRES IS BUILDING IN ACROSS THE GULF IN THE WAKE OF THE FRONT...AND IS USHERING IN A VERY DRY AND COLD AIR MASS ACROSS THE AREA. THE STRONG NW WINDS LEFT BEHIND THE FRONT ARE GRADUALLY DIMINISHING AS THE HIGH CONTINUES TO SETTLE IN ACROSS THE AREA FROM NW TO SE. CURRENT AND LATEST BUOY OBSERVATIONS ARE SHOWING NW WINDS OF 20-25 KT IN THE MIDDLE AND EASTERN ZONE WITH SEAS OF 8 TO 12 FT IN A NW SWELL. NW WINDS OF 15-20 KT ARE NOTED IN THE SW ZONE E OF 95W...AND IN THE NE PART OF THE NW ZONE. BUOY REPORTS THERE ARE SHOWING SEAS OF 8-13 FT IN A N SWELL IN THE SW ZONE TO THE E OF 95W...AND 6-8 FT IN THE NE PART OF THE NW ZONE. ELSEWHERE OVER THE WESTERN GULF...WINDS HAVE DIMINISHED TO NW-N 10-15 KT WITH SEAS 5-8 FT W OF 95W IN THE SW ZONE...AND DOWN TO 2-4 FT OVER THE FAR NW GULF. MODELS SUGGEST THAT THE HIGH WILL BECOME ORIENTED NE TO SW OVER THE WESTERN PORTION THROUGH SUN...THEN BECOME WEAKENING HIGH CENTER LATE SUN INTO MON. WINDS AND SEAS WILL BE ON THE RATHER LOW SIDE THROUGH MON...WITH THE EXCEPTION OF THE SE WATERS. A TIGHTER PRES GRADIENT THERE BETWEEN THE RIDGE AND THE OLD FRONTAL BOUNDARY OVER THE WESTERN CARIBBEAN RETREATING BACK TO THE W WILL ALLOW FOR N WINDS OF 15-20 KT SUN AND MON WITH SEAS OF ABOUT 3-6 FT THERE AND IN THE SOUTHERN PORTION OF THE MIDDLE GULF. THE REMAINDER OF THE GULF SHOULD SEE SEAS SUBSIDING TO 2-4 FT FROM LATE FRI THROUGH MON. CARIBBEAN SEA AND TROPICAL N ATLC... THE COLD FRONT THAT SWEPT THROUGH THE GULF OF MEXICO YESTERDAY ENTERED THE NW CARIBBEAN LAST NIGHT. THE PRELIMINARY 0600 UTC SURFACE ANALYSIS HAS THE FRONT EXTENDING FROM WESTERN CUBA SW TO INLAND BELIZE AND GUATEMALA. THE PRE-FRONTAL TROUGH EXTENDS FROM CENTRAL CUBA S TO NEAR 14N82W. BUOY 42056 AT 19.8N85W IS NOW REPORTING NW WINDS OF 20-25 KT WITH A COMBINED SEA STATE OF 7 FT. SHIP WITH CALLER ID "H3VR" IN THE GULF OF HONDURAS IS REPORTING A W WIND OF 20 KT WITH SEAS OF 5 FT. ANOTHER SHIP JUST NE OF BELIZE IS REPORTING NE WINDS OF 25 KT WITH SEAS TO 10 FT IN A NE SWELL. BUOY 42057 AT 17N81.6W IS REPORTING A N WIND OF 15-20 KT AS THE TROUGH PASSES OVER IT. SEAS ARE SLOWLY SUBSIDING BEHIND THE FRONT. THE REMAINDER OF THE AREA REMAINS UNDER A RATHER WEAK PRES PATTERN ALLOWING FOR MAINLY E WINDS OF 10-15 KT WITH SEAS OF 2-4 FT. THE TROPICAL N ATLC IS UNDER NE-E WINDS OF 10-15 KT...EXCEPT WITH A SWATH OF 15-20 KT WINDS SEEN FROM 12N-15N E OF 57W. SEAS IN THAT ZONE ARE 3-5 FT...EXCEPT 5-7 FT WITHIN THE SWATH OF 15-20 KT. THE COLD FRONT WILL MERGE WITH THE TROUGH THIS AFTERNOON...AND REACH FROM CENTRAL CUBA TO NE HONDURAS TONIGHT...FROM NEAR EASTERN CUBA TO SE NICARAGUA BY FRI..AND STALL ALONG THAT PSN. THE NW 20-25 KT WINDS BEHIND THE FRONT WILL ONLY DIMINISH SLIGHTLY THROUGH MON AS THE PRES GRADIENT BEHIND THE FRONT MAY BE SUSTAINED IF LOW PRES TO ITS S MATERIALIZES. MODELS SUGGEST THAT BY LATE FRI THE FRONTAL REMNANTS WILL BEGIN TO DRIFT W ACROSS THE NW CARIBBEAN SEA INTO MON AS CENTRAL ATLC HIGH PRES BUILDS SWD...AND LOW PRES BEGINS TO TAKE FORM OVER THE SW CARIBBEAN AS GLOBAL MODELS SUGGEST. THERE ARE SOME INDICATIONS THIS MAY ALREADY BE OCCURRING. PRESENTLY...SATELLITE IMAGERY DEPICTS A LARGE AREA OF NUMEROUS TSTMS COVERING THE SECTION OF THE CARIBBEAN FROM 14N TO 19N AND W OF 80W PART OF A BROAD AREA OF LOW PRES. IR ENHANCED NIGHT TIME SATELLITE IMAGERY SHOWS WHAT APPEARS TO BE A CYCLONIC CIRCULATION ALREADY IN PLACE ON THE TAIL END OF THE TROUGH NEAR 14N82W. THIS MAY ACTUALLY BE THE FIRST SIGNS OF LOW PRES FORMING IN THE SW CARIBBEAN SEA AS VORTICITY IN PLACE INDUCED BY THE NLY FLOW W OF THE FRONT OPPOSING WLY FLOW S OF 14N PROVIDES THE NECESSARY CYCLONIC SPIN NECESSARY FOR ORGANIZATION OF THESE CLOUDS AND TSTMS . THIS ACTIVITY IS ALSO UNDER THE SW PERIPHERY OF AND UPPER LEVEL ANTICYCLONE PROVIDING VENTILATION ALOFT TO PROLONG TSTM ACTIVITY...PERHAPS INTO A MORE ORGANIZED SYSTEM IN THE NEAR FUTURE. IN ADDITION TO MONITORING UPDATED SATELLITE IMAGERY...WILL ALSO SEE WHAT THE NEXT MODEL RUNS REVEAL WITH RESPECT TO EXACT TIMING OF GENESIS OF THE LOW AND ITS ASSOCIATED PRES AND WIND FIELD. AS ANY ORGANIZATION WITH THE BROAD AREA OF CLOUDS AND TSTMS COULD HAVE SIGNIFICANT IMPACTS OVER PORTIONS OF THE WESTERN CARIBBEAN WITH RESPECT TO WINDS AND SEAS. OTHERWISE...A TROPICAL WAVE IS JUST ALONG 55W S OF 14N ENTERING THE EASTERN TROPICAL N ATLC MOVING W AT 10-15 KT. THE WAVE WILL REACH NEAR 60W/61W TONIGHT...THEN MOVE INTO THE FAR SE CARIBBEAN SEA FRI AND SAT...AND OVER THE REST OF THE EASTERN CARIBBEAN SUN AND MON. SW N ATLC S OF 31N W OF 55W... THE 0600 UTC PRELIMINARY SURFACE ANALYSIS SHOWS A COLD FRONT EXTENDING FROM 31N75W TO CENTRAL CUBA AS A HIGH PRES RIDGE EXTENDS FROM 29N65W TO THE SE BAHAMAS. SCATTERED TSTMS ARE WITHIN 90-120 NM SE OF THE FRONT N OF 25N...AND WITHIN 60 NM SE OF THE FRONT S OF 25N. W-NW WINDS OF 20-30 KT ARE BEHIND THE FRONT N OF 27N...AND NW-N 20 KT WINDS ARE S OF 27N. SLY GALE FORCE WINDS ARE E OF THE FRONT N OF 30N TO 73W. ELSEWHERE BUOY REPORTS ALONG WITH A FEW SHIP OBSERVATIONS AND PARTIAL ASCAT DATA SHOW LIGHTER E-SE WINDS OF GENERALLY 10-15 KT E OF 70W. SEAS ARE IN THE RANGE OF 3-5 FT...EXCEPT OVER THE WESTERN PORTION W OF 75W WHERE SEAS HAVE RAPIDLY BUILD TO 8 FT...AND TO 8-11 FT W OF THE FRONT. THE RIDGE WILL RETREAT NE THROUGH FRI NIGHT AS THE FRONT REACHES A PSN FROM NEAR 31N72W TO CENTRAL CUBA TODAY...THEN SLOWS DOWN AND BECOMES STATIONARY FROM FROM NEAR 31N70W TO CENTRAL CUBA TONIGHT INTO FRI. THE FRONT OR TROUGH WILL BEGIN TO DRIFT W ON SUN AS CENTRAL ATLC HIGH PRES BUILDS S. WINDS BEHIND THE FRONT DIMINISH TO 15-20 KT TODAY...TO 10-15 KT TONIGHT ...THEN BEGIN TO SHIFT TO THE N-NE FRI NIGHT AND SAT AS HIGH PRES BUILDS IN FROM THE NW BEHIND THE WEAKENING FRONT. A TIGHTER PRES GRADIENT IN THE SW PORTION SHOULD ALLOW FOR HIGHER N-NE 20 KT WINDS TO EXIST S OF 26N THU THROUGH SAT...THEN DECREASE TO 10-15 KT SUN AND MON. ELSEWHERE E OF THE FRONT LITTLE CHANGE IS EXPECTED WITH THE WINDS TODAY AND TONIGHT ...THEN BECOME NE-E FRI THROUGH MON EXCEPT IN THE FAR E PORTION WHERE WINDS WILL VEER TO THE SE-S AND DIMINISH TO 5-10 KT WITH SEAS THERE 4-6 FT IN A NE SWELL. SEAS ELSEWHERE E OF THE FRONT WILL BE IN THE RANGE OF 3-5 FT...EXCEPT SUBSIDING TO 2-3 FT IN THE NW PORTION AND W OF THE NW BAHAMAS SAT AND SUN...THEN BUILD TO 3-5 FT IN AN E SWELL MON. WARNINGS...UPDATED GULF OF MEXICO... .NONE. .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE