000 AGXX40 KNHC 190859 AAA MIMATS MARINE WEATHER DISCUSSION...UPDATED NWS NATIONAL HURRICANE CENTER MIAMI FL 500 AM EDT WED OCT 19 2011 UPDATED WARNINGS SECTION 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... ...RAPID CHANGES TO CONDITIONS ARE UNDER WAY... THE 0600 UTC PRELIMINARY ANALYSIS SHOWS A 999 MB LOW OVER THE FAR NE GULF AT 29N84W WITH A FRONTAL TROUGH SSW TO THE YUCATAN CHANNEL. A RATHER STRONG COLD FRONT HAS PUSHED INTO THE GULF ...AND EXTENDS FROM NEAR PENSACOLA SW TO JUST S OF VERACRUZ MEXICO RACING NEAR 30 KT AS CONTINENTAL HIGH PRES BUILDS IN BEHIND IT USHERING IN THE FIRST COLD AIR MASS OF THE FALL SEASON. STRONG NW FLOW BEHIND THE FRONT HAS LEAD TO NW GALE FORCE WINDS OF 30-35 KT IN THE MIDDLE GULF ZONE N OF 26N PER PLATFORM AND BUOY OBSERVATIONS. SEAS IN THAT PART OF THE GULF HAVE BUILD INTO THE RANGE OF 8-12 FT. IN THE FAR NE PART OF THE NW GULF SOME GUSTS TO GALE FORCE ARE ALSO BEING NOTED BY OIL RIG PLATFORM THERE WITH SEAS UP TO 9 FT. WINDS ELSEWHERE ARE NW-N 20-30 KT ...EXCEPT NW 20 KT BETWEEN THE FRONTAL TROUGH AND THE FRONT AND S-SW 20-25 KT SE OF THE TROUGH AS SEEN IN BUOY REPORTS AND IN RECENT ASCAT PASSES. NW-N WINDS OF 25-30 KT IN THE FAR SW GULF MAY POSSIBLY REACH MINIMAL GALE FORCE FOR A SHORT DURATION THIS MORNING BEFORE DIMINISHING TO BACK 20-30 KT IN THE AFTERNOON. SEAS ARE IN THE RANGE OF 8-11 FT ELSEWHERE W OF FRONT TO LINE 30N92W TO VERACRUZ...AND 5-8 FT W OF THE SAME LINE. THE LOW WILL LIFT NE ACROSS THE FLORIDA BIG AREA AND N FLORIDA LATER THIS MORNING PUSHING THE FRONTAL TROUGH FURTHER INTO THE NW CARIBBEAN AS THE STRONG COLD FRONT QUICKLY ADVANCES TO THE EASTERN GULF...AND THEN TO E OF THE AREA EARLY THIS EVENING. THE HIGH BEHIND THE FRONT WILL CONTINUE TO BUILD ACROSS THE GULF THROUGH THU...THEN ALIGN ITSELF NE TO SW FROM SE LOUISIANA TO THE SW GULF FRI AND SAT. IN RESPONSE TO THIS ON FRI AND SAT...WINDS BECOME GENERALLY N-NE 15 KT E OF 91W WITH SPEEDS OF 15-20 KT S OF ABOUT 25N AND NE-E 10-15 KT W OF 91W EXCEPT W OF 93W WHERE THEY VEER TO MORE OF AN E-SE DIRECTION. SEAS SUBSIDE THROUGHOUT DURING DAYS 4 AND 5 IN RESPONSE TO DECAYING NW SWELL. CARIBBEAN SEA AND TROPICAL N ATLC... AS THE GULF OF MEXICO LIFTS NE DURING THE MORNING ITS ASSOCIATED FRONTAL TROUGH CURRENTLY EXTENDING S INTO THE YUCATAN CHANNEL WILL FURTHER SE INTO THE NW CARIBBEAN TODAY. AN ASCAT PASS FROM 0312 UTC LAST NIGHT SHOWED S-SW WINDS OF 20 KT N OF 17N W OF JAMAICA WITH COMBINED SEAS OF 7 FT. BUOY 42056 AT 19.8N85W IS REPORTING SW WINDS OF 15-20 KT. THE REMAINDER OF THE CARIBBEAN SEA IS UNDER MAINLY E WINDS OF 10-15 KT UNDER A RATHER WEAK PRES PATTERN WITH SEAS OF 2-4 FT. THE TROPICAL N ATLC IS UNDER NE-E WINDS OF 10-15 KT WITH SEAS OF 3-5 FT...EXCEPT 5-8 FT IN A NE SWELL FROM 12N-15N. THE VERY FAST MOVING STRONG GULF OF MEXICO COLD FRONT WILL SWEEP INTO THE NW CARIBBEAN THIS AFTERNOON AND OVERTAKE THE FRONTAL TROUGH. NW-N WINDS OF 20-25 KT WILL FOLLOW IN BEHIND THE FRONT WITH SEAS BUILDING TO 9 FT TODAY AND TONIGHT. THE FRONT WILL THEN REACH FROM CENTRAL CUBA TO NE HONDURAS TONIGHT...THEN FROM NEAR EASTERN CUBA TO SE NICARAGUA BY THU AFTERNOON...AND STALL THERE THROUGH SAT WHILE WEAKENING. MODELS SUGGEST THAT BY SUN THE FRONT BEGINS TO DRIFT WNW AS CENTRAL ATLC HIGH PRES BUILDS SWD. THE SURGE OF NW-N 20-25 KT WINDS WILL CONTINUE BEHIND THE FRONT WITH POSSIBLE GUSTS TO 30 KT. SEAS BUILD UP TO 9 FT BEHIND THE FRONT...EXCEPT HIGHER SEAS OF 8-10 FT IN NW SWELLS WILL MOVE INTO THE YUCATAN CHANNEL THROUGH THU AFTERNOON...AND SUBSIDE TO 5 FT FRI THROUGH SUN. OTHERWISE...A WEAKENING TROPICAL WAVE IS OVER THE CARIBBEAN ALONG 71W/72W S OF 17N MOVING W AT 10-15 KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED E OF THE WAVE AIS. THE WAVE WILL GRADUALLY DISSIPATE THROUGH THE NEXT 24-36 HRS. NE-E 15-20 KT WINDS AND SEAS TO 8 FT SHOULD CONTINUE THROUGH EARLY THU ACROSS THE MIDDLE TROPICAL N ATLC IN THE WAKE OF THE WAVE. ANOTHER TROPICAL WAVE WITH A LOWER AMPLITUDE WILL APPROACH THE TROPICAL N ATLC THU...AND THE LESSER ANTILLES EARLY FRI...AND INTO THE EASTERN CARIBBEAN SAT AND SUN. SW N ATLC S OF 31N W OF 55W... THE 0600 UTC PRELIMINARY SURFACE ANALYSIS SHOWS A NE-SW HIGH PRES RIDGE ACROSS THE FAR SE PORTION. TO THE W OF THE RIDGE... BROAD LOW PRES PREVAILS. LATEST SATELLITE IMAGERY AND NWS DOPPLER RADAR DISPLAYS SHOW NUMEROUS STRONG CONVECTION RAPIDLY INCREASING AHEAD OF THE GULF OF MEXICO LOW AND TROUGH. VERY STRONG SLY FLOW OF 20-30 KT COVERS THE WESTERN WATERS WITH GALE FORCE WINDS OF 30-40 KT N OF ABOUT 27N W OF 74W. AS A RESULT A GALE WARNING IS CURRENTLY IN EFFECT FOR MUCH OF THOSE WATERS. ELSEWHERE BUOY REPORTS ALONG WITH A FEW SHIP OBSERVATIONS AND PARTIAL ASCAT DATA SHOW LIGHTER E-SE WINDS OF GENERALLY 10-15 KT. 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 8-10 FT N OF 28N. THE RIDGE WILL RETREAT NE THROUGH FRI IN RESPONSE TO THE GULF OF MEXICO LOW PRES SYSTEM ACCELERATING NORTHEASTWARD...AND AS THE STRONG GULF OF MEXICO COLD FRONT MERGES WITH THE EASTERN GULF FRONTAL TROUGH...AND MOVES INTO THE NW WATERS LATER THIS MORNING. SEAS WILL BUILD TO 9-15 FT IN THE SLY GALE WIND FLOW TODAY IN ADVANCE OF THE FRONT. WINDS W OF THE FRONT WILL BECOME WNW 20-25 KT WITH SEAS OF 8-10 FT N OF 27N...AND NW-N 20 KT S OF 27N WITH SEAS UP 6 FT. THE COLD FRONT IS FORECAST TO REACH A PSN FROM NEAR 31N78W TO S FLORIDA THIS AFTERNOON...AND FROM 31N74W TO CENTRAL CUBA BY LATE TONIGHT AS IT STARTS TO SLOW DOWN. THE SLY GALE WINDS WILL DIMINISH TO 25-30 KT TONIGHT... BUT SEAS UP TO 13 FT WILL BE EVIDENT WITHIN 180 NM E OF THE FRONT N OF 29N. BY FRI IT SHOULD TRANSITION TO A STATIONARY FRONT FROM NEAR 31N7OW TO EASTERN CUBA...AND REMAIN ALONG THAT POSITION THROUGH SAT. THE FRONT OR TROUGH WILL BEGIN TO DRIFT W ON SUN AS CENTRAL ATLC HIGH PRES BUILDS S. W-NW 20-25 KT WINDS BEHIND THE FRONT QUICKLY DIMINISH TO 10-15 KT THU AND FRI...AND BEGIN TO SHIFT TO THE N-NE SAT AND SUN 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. ELSEWHERE E OF THE FRONT LITTLE CHANGE IS EXPECTED WITH THE WINDS THROUGH THU...THEN BECOME NE-E FRI THROUGH SUN 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. WARNINGS...UPDATED GULF OF MEXICO... .GMZ084...GALE WARNING N OF 26N... .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .AMZ080...GALE WARNING FROM 27N TO 29N W OF 74W AND N OF 27N BETWEEN 73W COLD FRONT... FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE