000 AGXX40 KNHC 072001 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT MON NOV 07 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... THE PRELIMINARY 18 UTC SURFACE ANALYSIS SHOWS A HIGH PRES RIDGE EXTENDING FROM THE NE GULF SW TO THE FAR SW BAY OF CAMPECHE TO BE THE MAIN FEATURE. IN THE UPPER LEVELS...BROAD SCALE RIDGING COVERS THE ENTIRE GULF AND SE U.S. BUOYS OBSERVATIONS THROUGHOUT SHOW GENERALLY E-SE WINDS OF 15-20 KT THROUGHOUT...EXCEPT ON THE E SIDE SIDE OF THE RIDGE E OF ABOUT 87W WHERE WINDS ARE NE-E 15-20 KT. THE BUOYS ALSO REVEAL THAT SEAS ARE 3-5 FT ACROSS THE GULF...EXCEPT S OF 25N E OF 90W WHERE SEAS ARE AT TIMES UP TO 8 FT UNDER A STEADY NE 20 KT WIND. THE FORECAST WILL HAVE THE BROAD SCALE UPPER RIDGE BEGINNING TO SLIDE EASTWARD TONIGHT...AND THROUGH WED NIGHT FORCING THE SURFACE RIDGE TO DUE TO THE SAME. THIS WILL BE IN RESPONSE TO A DEEP LAYER TROUGH OVER THE SW U.S. PRESSING EASTWARD. THIS TROUGH WILL PUSH THE ASSOCIATED SURFACE COLD FRONT OFF THE TEXAS COAST TUE NIGHT. THE LATEST MODEL RUNS ARE IN VERY GOOD AGREEMENT WITH TIMING OF THE FRONT MOVING OFF THE COAST AT THAT TIME. MUCH LIKE RECENT COLD FRONTAL EPISODES...THE FRONT WILL RAPIDLY MOVE E TO ALONG A PSN FROM SE LOUISIANA TO WESTERN BAY OF CAMPECHE WED...AND FROM NE FLORIDA TO FAR EASTERN BAY OF CAMPECHE BY LATE THU. THE FRONT WILL THEN MOVE TO JUST SE OF THE GULF EARLY FRI. STRONG OFFSHORE FLOW BEHIND THE FRONT WILL LEAD TO GALE FORCE WINDS (30-40 KT) AND BUILDING SEAS OF ABOUT 12-15 FT OVER THE FAR SW GULF ON THU BEFORE DIMINISHING ON FRI AS HIGH PRES THAT BUILDS IN BEHIND THE FRONT WEAKENS AND SHIFTS EASTWARD THROUGH SAT. SW N ATLC S OF 31N W OF 55W... SATELLITE IMAGERY ALONG WITH BUOY OBSERVATIONS FROM EARLY THIS AFTERNOON SHOW THE 1005 MB GALE CENTER NEAR 28N69W WITH ITS DECAYING FRONTAL STRUCTURE NE TO 30N65W AND SW TO NEAR PUERTO RICO. WATER VAPOR IMAGERY REVEALS THAT THE UPPER LEVEL LOW IS RIGHT OVER THE GALE CENTER LOW. AN ASCAT PASS FROM NEAR 1406 UTC THIS MORNING VIVIDLY REVEALED A LARGE SWATH OF N-NE GALE WINDS OF 30-40 KT TO THE N OF 27N AND E OF 73W. BUOY OBSERVATIONS AND THE SAME ASCAT PASS SHOW N-NE WINDS OF 20-30 KT ELSEWHERE N OF 24N AND BETWEEN 71W AND 75W. LIGHTER WINDS FROM NE AT 20 KT ARE W OF 75W. SEAS RANGE FROM 14-17 FT N OF 25N E OF 73W...TO 8-12 FT ELSEWHERE EXCEPT S OF 23N E OF THE DISSIPATING FRONT WHERE SEAS ARE 6-9 FT IN A N SWELL. AS FOR MODEL INTERPRETATIONS...THE LATEST RUNS ARE IN RATHER GOOD AGREEMENT THAT THE LOW WILL WILL MOVE SLOWLY WNW THROUGH ABOUT WED AFTERNOON AT PSN OF NEAR 28N71W...BEFORE TURNING MORE TO THE NW AND N LATER ON WED. THE LOW WILL HAVE HAS A HIGH CHANCE OF INTENSIFYING INTO A SUBTROPICAL CYCLONE. HOWEVER...THE ISSUE WITH THIS FEATURE WILL BE THE STRONG PRES GRADIENT BETWEEN THE LOW AND STRONG HIGH PRES N OF THE AREA. THIS GRADIENT WILL CONTINUE TO RESULT IN GALE CONDITIONS OVER MUCH OF THE NORTHERN WATERS THROUGH AT LEAST WED...BUT MAY BE EXTENDED BASED ON ANY FUTURE STRENGTHENING THE LOW UNDERTAKES. ANOTHER MAIN ISSUE AFFECTING JUST ABOUT THE ENTIRE ZONE WILL BE VERY LARGE LARGE SEAS IN THE LONG PERIOD N-NE SWELLS. THESE SWELLS WILL BE VERY SLOW IN SUBSIDING...SO SEAS WILL STAY HIGH OVER MUCH OF THE ZONE THROUGH AT LEAST THU AFTERNOON. IN ADDITION...NW-N SWELLS WILL CONTINUE TO BRING SEAS OF UP TO 8 FT THROUGH EXPOSED ATLC PASSAGES IN THE NE CARIBBEAN TILL ABOUT EARLY WED. BY EARLY ON THU THE LOW SHOULD BE NEAR 29N71W. ALL MODELS DO AGREE THAT THE LOW WILL BE PULLED NORTHWARD OF THE SW N ATLC ON THU AHEAD OF AN APPROACHING COLD FRONT. THE LOW WILL TRAIL A TROUGH FROM 31N70W TO WINDWARD PASSAGE...AND FROM 31N67W TO NEAR HAITI BY LATE FRI AFTERNOON. THE COLD FRONT WILL REACH FROM NEAR 31N70W SW TO CENTRAL CUBA BY LATE FRI...AND WEAKEN FROM NEAR 26N65W SW TO HISPANIOLA BY LATE SAT. NW-NE WINDS OF 20-25 KT WILL BE USHERED IN BEHIND THE FRONT IN THE FAR NW PORTION LATE THU INTO FRI...THEN VEER TO N-NE AND DECREASE TO 15-20 KT THROUGHOUT THE AREA BEHIND THE FRONT INTO SAT AS IT WEAKENS. SEAS WILL BUILD UP TO 10 FT BEHIND THE FRONT MAINLY OVER THE N CENTRAL WATERS. CARIBBEAN SEA AND TROPICAL N ATLC... SATELLITE IMAGERY REVEALS THE ATLC WEAKENING COLD FRONT EXTENDING SW FROM THE MONA PASSAGE TO NEAR 18N68W WILL CONTINUE TO WEAKEN INTO A TROUGH THROUGH TUE. A PARTIAL ASCAT PASS FROM NEAR 1410 SHOWED LIGHT NE WINDS OF 10 KT BETWEEN 70W-75W. AN INVERTED SURFACE TROUGH EXTENDS FROM 18N68W SW TO NW COLOMBIA. NE-E WINDS OF 15 KT ARE S OF 14N BETWEEN 73W-75W. E-SE WINDS 0F 10-15 KT ARE TO THE E OF THE TROUGH. CURRENT AND LATEST BUOY OBSERVATIONS SHOW SEAS IN THE GENERAL RANGE OF 2-3 FT OVER MOST OF THE ZONES...EXCEPT S OF 16N BETWEEN 75W AND 77W WHERE SEAS ARE SLIGHTER HIGHER (3-5 FT). HIGH PRES FROM THE EASTERN U.S. EXTENDING S INTO THE NW CARIBBEAN WILL BEGIN TO WEAKEN TONIGHT THROUGH THU AS LOW PRES DRIFTS W OVER THE WESTERN ATLC. THE INVERTED TROUGH WILL REMAIN STATIONARY THROUGH TONIGHT THEN WEAKEN TUE THROUGH WED. LARGE LONG PERIOD NW AND N SWELLS WILL CONTINUE TO PROPAGATE THROUGH NE ATLC PASSAGES INTO EARLY WED WITH UP TO 7 OR 8 FT. WARNINGS... GULF OF MEXICO... .GMZ082...GALE CONDITIONS EXPECTED THU S OF 21N W OF 94W... .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. .SW N ATLC... .AMZ080...GALE WARNING N OF 27N BETWEEN 67W AND 73W... FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE