000 AGXX40 KNHC 011830 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT SAT SEP 01 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... 1022 MB HIGH PRES LOCATED OVER CENTRAL GEORGIA EXTENDS A RIDGE SW ACROSS THE GULF WATERS. PRES GRADIENT BETWEEN THE RIDGE AND A TROUGH EXTENDING ACROSS TEXAS IS SUPPORTING FRESH SE TO S FLOW OVER THE WESTERN GULF...AS REGISTERED BY BUOY OBSERVATIONS AND MOST RECENT SCATTEROMETER PASSES. THE HIGH PRES IS FORECAST TO BUILD ACROSS THE GULF WITH A WEAK CELL DEVELOPING OVER THE NE PORTION OF THE AREA. UNDER THE INFLUENCE OF THIS SYSTEM... EXPECT GENERALLY LIGHT E TO SE FLOW S OF THE RIDGE AXIS...AND LIGHT SW WINDS N OF THE AXIS. SEAS WILL CONTINUE TO SUBSIDE WITH 2-3 FT OR LESS PREVAILING MON INTO WED. EXPECT ALSO FRESH WINDS NEAR THE COAST OF YUCATAN AT NIGHT DUE TO LOCAL EFFECTS. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... TROPICAL STORM LESLIE...CENTERED NEAR 18.3N 55.7W AT 1500 UTC IS EXPECTED TO CONTINUE TO TRACK WNW ACROSS THE FAR NE PORTION OF ZONE AMZ127...ATLANTIC FROM 19N TO 22N BETWEEN 55W AND 65W... THROUGH THIS EVENING. IT SEEMS LIKE THE WINDOW FOR LESLIE TO BECOME A HURRICANE IS CLOSING AS NORTHWESTERLY SHEAR HAS INCREASED. NOW...THE OFFICIAL INTENSITY FORECAST CALLS FOR LESLIE TO BECOME A MINIMAL HURRICANE IN ABOUT 72 HOURS OR BY TUE. IT WILL MOVE TO THE NE OF THE LEEWARD ISLANDS AND ABOUT 250 NM TO THE NORTHEAST OF ST MARTEEN BY SUN MORNING...AND IS FORECAST TO RECURVE N ALONG 62N/63N THROUGH WED. FOR ZONE AMZ127...TROPICAL STORM FORCE WINDS ARE FORECAST STARTING LATE THIS AFTERNOON AND TONIGHT E OF 60W...WITH SEAS BUILDING AS HIGH AS 22 FT. OTHERWISE THE MAIN ISSUE WILL BE EASTERLY SWELL GENERATED FROM LESLIE. WHILE THE TROPICAL STORM OR HIGHER WINDS FROM LESLIE ARE NOT EXPECTED TO BE WEST OF 65W...SE SWELLS GENERATED FROM LESLIE WILL RAISE SEAS 8 TO 16 FT RANGE E OF 70W BY MON MORNING...AND 8 TO 14 FT RANGE E OF 75W BY TUE MORNING. ELSEWHERE WEAK HIGH PRES WILL REMAIN CENTERED BETWEEN THE GEORGIA COAST AND BERMUDA THROUGH TUE...MAINTAINING LIGHT TO MODERATE EASTERN FLOW THROUGHOUT THE PERIOD. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... SURFACE RIDGING N OF THE AREA WILL MAINTAIN FRESH TO STRONG ELY WINDS ACROSS THE S CENTRAL CARIBBEAN THE REST OF TODAY AND TONIGHT THEN WILL DIMINISH TO 15 TO 20 KT AS THE HIGH PRES WEAKENS. SCATTEROMETER DATA ALONG WITH A PAIR OF SHIP OBSERVATIONS SHOWED WINDS OF 20-25 KT NEAR THE COAST OF COLOMBIA RAISING SEAS TO 8 FT. TRADES ACROSS THE REMAINDER OF THE CARIBBEAN DIMINISH FURTHER THROUGH EARLY NEXT WEEK AS THE HIGH PRES N OF THE AREA WEAKENS AHEAD OF AN APPROACHING TROPICAL CYCLONE. THE MAIN ISSUE WILL BE THE DEVELOPMENT AND TRACK OF TROPICAL STORM LESLIE...CENTERED NEAR 18.3N 55.7W AT 1500 UTC. LESLIE WILL MOVE TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 16 KT. A TURN TOWARD THE NORTHWEST WITH A DECREASE IN FORWARD SPEED IS EXPECTED TONIGHT AND SHOULD CONTINUE THROUGH SUNDAY. ON THE FORECAST TRACK...THE CENTER OF LESLIE IS EXPECTED TO PASS WELL TO THE NORTHEAST OF THE LEEWARD ISLANDS. CURRENTLY...THE MAIN IMPACT ON THOSE ISLANDS WILL BE THE SWELLS GENERATING BY LESLIE...EXPECTED LATE TODAY WITH SEAS REACHING IN EXCESS OF 10 FT AND PERIODS OF NEAR 15 SECONDS. A TROPICAL STORM WARNING IS IN EFFECT FOR ZONE AMZ027...TROPICAL N ATLANTIC FROM 15N TO 19N BETWEEN 55W AND 60W. OF NOTE...EIGHT TROPICAL STORMS FORMED IN THE ATLANTIC BASIN DURING THE MONTH OF AUGUST. THIS TIES THE ALL-TIME RECORD FOR THE NUMBER OF NAMED STORMS FORMING IN THE MONTH OF AUGUST... WHICH WAS SET IN 2004. FOUR OF THE TROPICAL STORMS BECAME HURRICANES DURING THE MONTH. THEY WERE ERNESTO... GORDON...ISAAC AND KIRK. THESE TOTALS WERE WELL ABOVE THE LONG-TERM AVERAGE (1981 TO 2010) OF THREE NAMED STORMS... WITH ONE OR TWO HURRICANES. NO MAJOR HURRICANES OCCURRED THIS AUGUST...WHILE A MAJOR HURRICANE TYPICALLY OCCURS IN AUGUST ABOUT ONCE EVERY TWO YEARS. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N... .AMZ027...TROPICAL STORM WARNING THROUGH TONIGHT. SW N ATLANTIC... .AMZ127...TROPICAL STORM WARNING. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER GR