000 AGXX40 KNHC 270758 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 355 AM EDT MON AUG 27 2012 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 06 UTC SURFACE ANALYSIS HAS A RIDGE EXTENDING FROM THE SE U.S. SW TO THE SW GULF OF MEXICO...WHILE TROPICAL STORM ISAAC IS NOW ENTERED THE FAR SE GULF NEAR 24.8N 83.5W AS OF 2 AM EDT THIS MORNING. OUTSIDE THE VICINITY OF ISAAC ...BUOYS AND OIL RIG PLATFORMS ARE REPORTING NE-E WINDS OF 10-15 KT N OF 24N W OF 91W...WITH SEAS OF 2-4 FT AND 3-5 FT S OF 24N. E OF 91W WINDS ARE RAPIDLY INCREASING DUE TO THE TIGHT PRES ASSOCIATED WITH ISAAC. BUOY 42003 AT 26N86W IS REPORTING NE 25 KT WINDS WITH COMBINED SEAS OF 13 FT AS OF 0615 UTC...AND BUOY 42036 AT 28N84W HAS NE 30 KT WINDS WITH COMBINED SEAS OF 10 FT. THESE VALUES ARE PRETTY REASONABLE COMPARED TO THE NOAA WAVEWATCH III GUIDANCE VALUES. WILL RELY ON GUIDANCE FOR FORECAST UP TO 36 HRS...THEN MAY NEED TO ADJUST VALUES UPWARDS SOME AS ISAAC APPROACHES THE FAR N CENTRAL GULF WATERS BEYOND THAT TIME FRAME. ISAAC PRESENTLY TRACKING WNW IS FORECAST TO TURN NW LATER TODAY AS IT CONTINUES TO STRENGTHEN. THE 0300 UTC NHC ADVISORY FROM LAST NIGHT HAS ISAAC FORECAST TO STRENGTHEN TO 60 KT GUSTS TO 75 KT NEAR 25.2N 84.8W THIS MORNING...AND INTO A MINIMAL HURRICANE NEAR 26.5N 86.7W EARLY TONIGHT...TO NEAR 27.9N 88.3W WITH 80 KT GUSTS TO 100 KT TUE MORNING...TO NEAR 28.9N 89.3W WITH 85 KT GUSTS TO 105 KT BY EARLY TUE EVENING...AND INLAND NEAR 30.6N 90.3W BY EARLY WED EVENING. ISAAC WILL HAVE A SIGNIFICANT IMPACT ON WINDS AND SEAS OVER MUCH OF THE ERN AND MIDDLE GULF WATERS THROUGH THE FORECAST PERIOD. ASSOCIATED SEAS WILL VARY GREATLY IN ITS PERIPHERY AS WELL WITH SWELLS OF ABOUT THE 6-9 FT RANGE RADIATING OUTWARD INTO MOST OF THE MIDDLE PORTION OF THE GULF. SEAS SHOULD SUBSIDE TO 8 FT OVER THE N CENTRAL GULF THU NIGHT AND FRI...AND REMAIN IN THE RANGE OF 3-5 FT ELSEWHERE EXCEPT LOWER IN THE RANGE OF 2-3 FT IN THE FAR SE AND SW ZONES. SOUTHWEST NORTH ATLC S OF 31N W OF 65W... THE PRELIMINARY 06 UTC SURFACE ANALYSIS HAS A RIDGE EXTENDING SW OVER THE ERN PORTION OF THE NW WATERS. THE LARGE CIRCULATION ASSOCIATED WITH ISAAC IS RESULTING IN SE-S WINDS OF 20-30 KT S OF 27N W OF 78W...AND E-SE WINDS OF 20-25 KT S OF 29N BETWEEN 73W AND 78W. THE 0158 UTC ASCAT PASS NICELY CAPTURED THESE WINDS. BUOYS ARE REPORTING SEAS IN THE RANGE OF 8-11 FT IN FAR WRN PORTION S OF 27N. WINDS ARE E-SE 10-15 KT ELSEWHERE WITH SEAS OF 3-5 FT. THE STRONG WINDS AND HIGH SEAS JUST DESCRIBED OVER MOST OF THE WRN SECTION OF THE FORECAST ZONES WILL GRADUALLY SUBSIDE INTO TUE MORNING. THE RIDGE OVER THE ERN PORTION OF THE AREA WILL REALIGNED ITSELF ALONG 28N TUE THROUGH WED...THEN SHIFT SLIGHTLY S WED NIGHT THROUGH FRI IN RESPONSE TO A WEAK COLD FRONT THAT BRUSHES ACROSS THE FAR NRN WATERS. BOTH GFS AND ECMWF BOUNDARY LAYER WIND GUIDANCE SUGGEST THAT FRONT MAY BE PRECEDED BY SW 15 KT WINDS. WAVEWATCH GUIDANCE INDICATES THAT SEAS SHOULD BE 4-6 FT AHEAD OF THE FRONT. THE RIDGE WILL BECOME THE DOMINATE WEATHER FEATURE FOR THIS FORECAST PERIOD...AND MAINTAIN LIGHT E-SE WINDS THROUGHOUT WITH THE EXCEPTIONS OF WINDS BECOMING N-NE 10 KT BEHIND THE FRONT AND E WINDS OF 15 KT S OF 25N E OF THE BAHAMAS. SEAS ELSEWHERE SHOULD BE IN THE 3-5 FT RANGE...LOWERING TO 2-3 FT IN NW PORTION WED NIGHT THROUGH FRI. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... NOW THAT TROPICAL STORM ISAAC HAS PULLED FURTHER AWAY FROM THE THE NW CARIBBEAN SEA...CONDITIONS THERE ARE SUBSIDING ALTHOUGH THAT PART OF THE CARIBBEAN IS STILL UNDER THE INFLUENCE OF THE BROAD CYCLONIC CIRCULATION ASSOCIATED WITH ISAAC. BUOY 42056 AT 20N85W HAS NW WINDS OF 10 KT WITH SEAS OF 3-4 FT IN A N SWELL. HOWEVER SHIP "HPYE" IN THE YUCATAN CHANNEL IS REPORTING SEAS OF 7 FT IN A N SWELL. THE 0158 ASCAT PASS DID NOTED A SWATH OF SE 20-25 KT WINDS COVERING MOST OF THE CENTRAL CARIBBEAN SEA N OF 13N BETWEEN 72W AND 78W. BUOY 42058 AT 15N75W IS CURRENTLY REPORTING E WINDS OF 20 KT WITH SEAS OF 6-7 FT. WINDS BECOME SE 15-20 KT IN THE NW PORTION OF THE CARIBBEAN BEGINNING LATE TONIGHT AND CONTINUE INTO THU BEFORE DIMINISHING TO 10-15 KT DURING THU AND INTO FRI. SEAS THERE WILL BE IN THE 3-5 FT RANGE...HOWEVER HIGHER SEAS OF 5-7 FT IN A N SWELL OVER THE WATERS NEAR THE YUCATAN CHANNEL AND THROUGH THE YUCATAN CHANNEL WILL LAST UNTIL ABOUT EARLY WED. BOTH THE GFS AND ECMWF BOUNDARY LAYER WIND FIELDS INDICATE THAT THE TIGHT PRES GRADIENT BRINGING THE SE 20-25 WINDS ACROSS THE CENTRAL CARIBBEAN WILL CONTINUE INTO THROUGH FRI...BUT DECREASE SOME IN AREAL COVERAGE ON FRI AS CENTRAL ATLC HIGH PRES SHIFTS EASTWARD. SEAS IN THAT PART OF THE CARIBBEAN WILL BUILD TO 8-10 FT DURING THIS PERIOD. NE-E WINDS OF 10 KT WILL CONTINUE ACROSS THE TROPICAL N ATLC ZONES N OF ABOUT 12N AND ELSEWHERE ACROSS THE CARIBBEAN...WHILE E-SE WINDS OF 10 KT WILL REMAIN S OF 12N. SEAS OF 3-5 FT IN A NE TO E SWELL LAST THROUGH TUE NIGHT BEFORE BECOMING MORE LIKE 2-4 FT BY WED. GLOBAL MODELS SUGGEST THAT THE NEXT CAPE VERDE LOW PRES SYSTEM MAY APPROACH THE FAR ERN TROPICAL ATLC ZONES FRI. THERE ARE TIMING DIFFERENCES WITH RESPECT TO THIS FEATURE AS IT MOVES W ACROSS THE TROPICAL ATLC. WILL HAVE TO WAIT FOR FUTURE MODELS TO SEE HOW THEY RESOLVE THIS MATTER BEFORE BE MORE DEFINITIVE ON A FORECAST FOR THIS FEATURE. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .HURRICANE WARNING...GMZ013 AND GMZ015. .TROPICAL STORM WARNING...GMZ021 CARIBBEAN SEA... .NONE.. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE