000 AGXX40 KNHC 190727 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 230 AM EDT WED OCT 19 2011 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 PRELIMINMARY 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 PENSACOLD SW TO JUST S OF VERACRUZE 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 O 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 AS THE RESIDUAL NW SWELL SUBSIDES. 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 WINDS UNDER A RATHER WEAK PRES PATTERN. THE TROPICAL N ATLC IS UNDER NE-E WINDS OF 10-15 KT. THE VERY FAST MOVING STRONG GULF OF MEXICO COLD FRONT WILL SWEEP INTO THE NW CARIBBEAN THIS AFTERNOON OVERTAKING 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. THE FRONT WILL THEN STALL THERE THROUGH SAT AND WEAKEN. 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 A 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 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 SURFACE ANALYSIS SHOWS A HIGH PRES RIDGE ALONG 31N. TO THE S OF THE RIDGE LATEST SATELLITE IMAGERY AND NWS DOPPLER RADAR DISPLAYS SHOW ABUNDANT DEEP LAYER MOISTURE COVERING JUST ABOUT THE AREA RESULTING IN WIDESPREAD AREAS OF RAIN WITH EMBEDDED SHOWERS AND SCATTERED TSTMS. E-SE WINDS OF 15-20 KT ARE EVIDENT S OF 28N W OF 76W. ELSEWHERE BUOY REPORTS ALONG WITH A FEW SHIP OBSERVATIONS AND PARTIAL ASCAT DATA SHOW LIGHTER E WINDS OF GENERALLY 10-15 KT. SEAS ARE IN THE RANGE OF 3-5 FT...EXCEPT LOWER SEAS OF 2-3 FT IN THE VICINITY OF THE BAHAMAS AS WELL AS N OF 28N W OF 70W. THE RIDGE WILL WEAKEN AND RETREAT NE THROUGH TUE NIGHT IN RESPONSE TO THE GULF OF MEXICO LOW PRES SYSTEM ACCELERATING NORTHEASTWARD AND THE APPROACHING COLD FRONT. A STRONG PRES GRADIENT FORMS OVER THE NW WATERS E OF THE FRONT TODAY KICKING OFF SLY WINDS 20-30 KT...TO HIGHER RANGES IN THE GALE FORCE RANGE OF 30-40 KT BY TONIGHT WITH SEAS IN THE 8-14 FT RANGE. 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 EXTEND FROM NEAR 31N78W TO S FLORIDA BY WED AFTERNOON. LATEST ENSEMBLE 34 KT WIND PROBABILITIES SHOW 20-40 PERCENT FOR GALE PROBABILITIES FOR TONIGHT INTO WED MORNING E OF THE FRONT TO 74W AND N OF 28N. BY WED AFTERNOON THE SLY GALE WINDS ARE FORECAST TO DIMINISH TO 25-30 KT. THE FRONT WILL THEN REACH FROM 31N74W TO CENTRAL CUBA BY EARLY THU AS IT BEGINS TO WEAKEN AND SLOW DOWN. BY FRI IT SHOULD TRANSITION TO A STATIONARY FRONT FROM NEAR 31N7OW TO CENTRAL CUBA...AND REMAIN ALONG THAT POSITION THROUGH SAT. W-NW 20-25 KT WINDS ARE EXPECTED BEHIND THE FRONT WED...EXCEPT TO THE N OF 27N CLOSER TO THE COAST WINDS COULD REACH UP TO 30 KT WITH SOME GUSTS TO NEAR GALE FORCE. WINDS THEN QUICKLY DIMINISH TO 10-15 KT THU AND FRI...AND SHIFT TO THE N-NE OVER THE SW PORTION AS HIGH PRES BUILDS IN FROM THE WNW 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. ELSEWHERE WINDS WILL BE GENERALLY E 10-15 KT THU THROUGH SAT WITH SEAS IN THE RANGE OF 3-5 FT...EXCEPT 2-3 FT IN THE NW PORTION. WARNINGS... GULF OF MEXICO... .GMZ084 AND GMZ086...GALE WARNING FROM 22N TO 28N BETWEEN 83W AND 85W... .GMZ082...GALE CONDITIONS EXPECTED S OF 21N W OF 95W EARLY WED... .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .AMZ080...GALE WARNING N OF 28N BETWEEN 74W AND COLD FRONT... FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE