000 AGXX40 KNHC 180843 AAA MIMATS MARINE WEATHER DISCUSSION...UPDATED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 500 AM EDT SAT SEP 18 2010 UPDATED WARNINGS AND TC INFORMATION MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... TROPICAL DEPRESSION KARL WAS LOCATED WELL INLAND NEAR 18.5N 97.6W AT 0400 AM CDT. KARL IS DISSIPATING AND THE LAST NHC ADVISORY HAS BEEN ISSUED. RAINFALL AMOUNTS OF 1 TO 3 INCHES REMAINS POSSIBLE OVER THE MOUNTAINOUS TERRAIN OF MEXICO WHICH CAN PRODUCE FLASH FLOODING AND MUDSLIDES. A 0308 UTC ASCAT PASS INDICATED THAT WINDS HAVE NOW DIMINISHED TO 10-15 KT OVER THE BAY OF CAMPECHE AND FAR SW GULF OF MEXICO AND SEAS HAVE SUBSIDED TO 5 FT AT NDBC BUOY 42055. MEANWHILE A TIGHT PRES GRADIENT REMAINS OVER THE NW GULF AROUND A RIDGE IN PLACE ACROSS THE N GULF COAST STATES AND THE ASCAT PASS ALSO CAPTURED E-SE WINDS OF 15-20 KT ACROSS THE NW GULF ZONE. WEAK RIDGING WILL REMAIN OVER THE GULF COAST STATES DURING THE PERIOD WHILE WEAK TROUGHING WILL DEVELOP EACH DAY OVER THE FAR SW GULF ALONG THE MEXICAN COAST. SW N ATLC... HURRICANE IGOR WAS LOCATED NEAR 25.1N 62.8W AT 0500 AM AST WITH HURRICANE AND TROPICAL STORM FORCE WINDS ALREADY IMPACTING THE E PORTION OF THE FORECAST WATERS. WINDS AND SEAS WILL CONTINUE TO INCREASE AND BUILD SPREADING INTO THE W PORTION THIS WEEKEND WITH VERY LARGE SWELLS IMPACTING THE SE U.S. COAST AND THE BAHAMAS. CONDITIONS WILL CONTINUE TO DETERIORATE IN BERMUDA THIS WEEKEND WITH THE CIRCULATION CENTER EXPECTED TO PASS NEARLY DIRECTLY OVER BERMUDA SUN NIGHT. IGOR WILL MOVE N OF THE AREA LATE SUN NIGHT INTO MON ALTHOUGH LARGE SWELLS WILL LINGER ACROSS THE WATERS THROUGH MID WEEK. ATLC RIDGING WILL BUILD DOWN FROM THE S IN THE WAKE OF IGOR LATE TUE AND WED. TROPICAL N ATLC AND CARIBBEAN SEA... HURRICANE IGOR WAS LOCATED NEAR 25.1N 62.8W AT 0500 AM AST. TROPICAL STORM FORCE WINDS HAVE NOW SHIFTED TO ALONG AND N OF 22N AND THUS THE TROPICAL STORM WARNING WILL BE DISCONTINUED FOR THE TROPICAL N ATLC WATERS WITH THE MORNING ISSUANCE. WINDS WILL CONTINUE TO DIMINISH THIS WEEKEND AS ATLC RIDGING SHARPLY NOSES DOWN THROUGH THE TROPICAL N ATLC AND INTO THE E CARIBBEAN ALTHOUGH NORTHERLY SWELLS RELATED TO IGOR WILL ONLY SLOWLY SUBSIDE OVER THE NORTHERN PORTION. THE RIDGING WILL WEAKEN BY TUE WITH WINDS BECOMING EASTERLY ACROSS THE TROPICAL N ATLC. A NEW SET OF NW-N SWELL WILL PROPAGATE DOWN INTO THE WATERS ON WED AROUND THE BACK SIDE OF IGOR. IN THE CARIBBEAN SEA...A WEAK AND ILL-DEFINED PRESSURE PATTERN WILL REMAIN IN PLACE OVER THE MAJORITY OF THE CARIBBEAN SEA THROUGH THE FORECAST PERIOD WITH MAINLY LIGHT AND VARIABLE WINDS AND LOW SEAS. THE EXCEPTION WILL BE OVER THE E CARIBBEAN WHERE SWELLS UP TO 10 FT RELATED TO IGOR WILL CONTINUE TO SEEP THROUGH THE ATLC PASSAGES. THESE SWELLS WILL SUBSIDE MON AND TUE ALTHOUGH THE ABOVE MENTIONED NEW SET OF NORTHERLY SWELL WILL ARRIVE AND PROPAGATE DOWN THROUGH EXPOSED ATLC PASSES LATE TUE AND WED. WARNINGS... SW N ATLC... .HURRICANE WARNING N OF 22N E OF 70W. CARIBBEAN... .NONE. TROPICAL N ATLC... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER LEWITSKY