000 AGXX40 KNHC 061847 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT THU SEP 06 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 MAIN FEATURE OVER THE AREA IS A WEAK LOW PRES SYSTEM THAT DROPPED S FROM THE SE U.S. INTO THE NORTHERN GULF ON WED...AND IS NOW ANALYZED NEAR 28N88W WITH A PRES OF 1012 MB AS A WEAK RIDGE PROTRUDES SW FROM THE ATLC ACROSS CENTRAL FL. LATEST SATELLITE IMAGERY SHOWS SCATTERED TSTMS WITHIN 120 NM OF THE LOW IN THE S SEMICIRCLE. WIND OBSERVATIONS NEAR THE LOW ARE REVEALING A SMALL POCKET OF S-SW WINDS OF 20-25 KT WITHIN ABOUT 90 NM OF THE LOW IN THE E SEMICIRCLE...HOWEVER SEAS ARE LOW IN THE 3-5 FT RANGE. SEAS MAY BE BRIEFLY HIGHER IN THE CONVECTION. THE LOW IS NOT PRESENTLY SHOWING SIGNS OF ORGANIZATION AS ITS CLOUD PATTERN STRUCTURE IS RATHER DISORGANIZED...HOWEVER IT STILL HAS SOME POTENTIAL FOR SOME TROPICAL CYCLONE DEVELOPMENT OVER THE NEXT COUPLE OF DAYS BEFORE ENVIRONMENTAL CONDITIONS BECOME UNFAVORABLE. GLOBAL MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE INITIAL POSITION OF THE LOW WITH BOTH THE GFS AND ECMWF BEING VERY CLOSE...AND ALSO WITH ITS FORECAST POSITIONS THROUGH NEXT 48 HRS. SO WILL WILL LEAN HEAVILY WITH GFS/ECMWF GUIDANCE FOR FORECAST OF THE LOW THROUGH SAT. WINDS MAY BRIEFLY INCREASE TO 20-25 KT OVER THE E SEMICIRCLE OF THE LOW THROUGH THE NEXT 24 TO 48 HRS AS IT NEAR 28N90W EARLY FRI...AND TO NEAR 28N88W BY EARLY SAT. BY THIS TIME...THE FIRST COLD FRONT ENTRY INTO THE GULF IS EXPECTED IN THE FAR WESTERN PORTION. MODELS AGREE THAT THIS FRONT WILL QUICKLY RACE EASTWARD TO A POSITION FROM NE FLORIDA SW TO 26N90W TO INLAND FAR SOUTHERN TEXAS OR FAR NE TEXAS BY EARLY SUN. AROUND THIS TIME THE FRONT IS EXPECTED TO ABSORB THE LOW AS STRONG HIGH PRES BUILDS EASTWARD OVER THE CENTRAL U.S. THE PRES GRADIENT BEHIND THE FRONT SHOULD BE TIGHT ENOUGH TO ALLOW FOR A BRIEF EPISODE OF N-NE 15-20 KT WINDS OVER THE WESTERN AND N CENTRAL PORTIONS OF THE GULF SUN BEFORE DIMINISHING TO 10-15 KT LATER IN THE DAY SUN WHILE VEERING TO THE NE EARLY ON MON AND TO THE E DURING MON AFTERNOON AND INTO TUE. SEAS BEHIND THE FRONT SHOULD BUILD TO NO HIGHER THAN 5-6 FT SUN BEFORE SUBSIDING TO 2-3 FT MON AND TUE. THE RIDGE TO THE N WILL CONTINUE TO SLIDE EASTWARD MON AND TUE. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... HURRICANE LESLIE E OF OF THE ZONES WAS NEAR 26.4N 62.4W AT 15 UTC DRIFTING NORTHWARD IN A WEAK STEERING ENVIRONMENT WITH MAXIMUM WINDS OF 65 KT WITH GUSTS TO 80 KT AND A MINIMAL CENTRAL PRES OF 985 MB AS OF 15 UTC. THE 15 UTC NHC ADVISORY FORECASTS LESLIE TO GRADUALLY INTENSIFY OVER THE NEXT FEW DAYS AS IT TRACKS IN A GENERAL N TO NW DIRECTION...ROUGHLY BETWEEN 62W-63W AS STEERED BY THE MECHANISMS OF THE REDEVELOPMENT OF THE SUBTROPICAL RIDGE TO ITS E AND A LARGE MID-LATITUDE TROUGH AND ASSOCIATED COLD FRONT THAT MOVES OFF THE EASTERN UNITED STATES COAST. PLEASE REFER TO NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC. THE RADIUS OF TROPICAL STORM FORCE WINDS WILL EXTEND INTO THE NE PORTION OF THE AMZ121 ZONE THROUGH FRI NIGHT AND THE EASTERN PORTION OF THE AMZ115 OFFSHORE ZONE THROUGH SUN AFTERNOON. A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE FAR EXTREME EASTERN PORTIONS OF THESE ZONES. LARGE LONG PERIOD SWELLS GENERATED BY LESLIE WILL AFFECT A LARGE SWATH OF THE FORECAST AREA INCLUDING BERMUDA AND THE U.S. EAST COAST FROM CENTRAL FLORIDA NORTHWARD INTO EARLY NEXT WEEK. THESE SWELLS WILL CARRY WITH THEM THE POTENTIAL FOR LIFE-THREATENING SURF CONDITIONS AND RIP CURRENTS. LATEST BUOY OBSERVATIONS FROM BUOY 41049 AT 27.5N 63W HAS COMBINED SEAS OF 30 FT. BUOY 41049 AT 32N69W W OF BERMUDA HAS COMBINED SEAS OF 9 FT IN A SE SWELL. BUOYS 41043 AT 21N65W AND BUOY 410497 AT 28N72W BOTH HAVE COMBINED SEAS OF 7 FT WITH THE SE SWELL COMPONENT N OF 26N...AND THE N SWELL COMPONENT S OF 26N. LIGHT WINDS WILL BE FOUND OVER THE WESTERN PART OF THE AREA THROUGH TUE WHERE A WEAK 1016 MB HIGH IS CENTERED NEAR 28N74W WITH A RIDGE SW ACROSS S CENTRAL FLORIDA. THE HIGH WILL SHIFT SLIGHTLY SW THROUGH THE NEXT 48 HRS BEFORE DISSIPATING. SEAS ARE 2-3 FT SW OF THE BAHAMAS AND SEAS IN THE RANGE OF 5-8 FT IN A NE SWELL TO THE NE OF THE BAHAMAS OUTSIDE THE 12 FT AND GREATER SEA HEIGHTS ASSOCIATED WITH LESLIE CONFINED TO THE NE AND E PORTIONS OF THE BASIN. THESE SEAS WILL LAST INTO EARLY SUN BEFORE THEY BEGIN TO SUBSIDE THROUGH TUE. A BROAD UPPER LEVEL LOW NE OF THE BAHAMAS NEAR 28N76W IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS...ALTHOUGH PRESENTLY WEAKER THAN EARLIER IN THE DAY...OVER THE NW BAHAMAS AND WATERS BETWEEN THE NW BAHAMAS AND 31N BETWEEN 77W AND 79W. THE LOW IS FORECAST TO SHEAR OUT TO THE NE THROUGH SAT NIGHT IN ADVANCE TO THE EAST COAST MID-LATITUDE TROUGH AND COLD FRONT. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... RESIDUAL LONG PERIOD MAINLY N SWELLS FROM LESLIE AFFECTING THE ATLC EXPOSURES OF THE NE CARIBBEAN AND WATERS NEAR HISPANIOLA ARE FORECAST TO LAST INTO EARLY SUN WHILE SLOWLY SUBSIDING. THESE SWELLS WILL RESULT IN SEAS OF AROUND 6-8 FT...THEN SUBSIDING TO 5-7 FT SUN AND 3-5 FT MON AND TUE. LIGHT TO MODERATE E WINDS WILL PERSIST ELSEWHERE OVER MOST OF THE REGION...EXCEPT UP TO 20 KT IN THE S CENTRAL CARIBBEAN...AND OCCASIONALLY 15-20 KT IN THE GULF OF HONDURAS MAINLY AT NIGHT. WAVE HEIGHTS WILL REMAIN 6 FT OR LESS. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .TROPICAL STORM WARNING N OF 26N E OF 66W...AMZ115 AND AMZ121. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE