000 AGXX40 KNHC 121834 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 234 PM EDT MON SEP 12 2016 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: 12Z GFS BLEND WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. WEAK CYCLONIC FLOW PERSISTS ACROSS MUCH OF THE GULF BASIN THIS AFTERNOON FOCUSED AROUND A 1013 MB LOW CENTERED NEAR 25N87W AND A SURFACE TROUGH ANALYZED N OF THE LOW FROM 27N86W TO THE FLORIDA BIG BEND REGION NEAR 30N83W. THIS AREA OF TROUGHING IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH OVER THE CENTRAL GULF WITH AXIS EXTENDING OVER THE LOWER MISSISSIPPI RIVER VALLEY ALONG 88W TO A BASE OVER THE SW GULF NEAR 21N93W. MOST ONGOING CONVECTION IS OCCURRING FROM 22N-29N BETWEEN 83W-88W. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF NW FLOW ALOFT WITH WATER VAPOR IMAGERY INDICATING DRYING OCCURRING OVER THE NW GULF. SKIES CONTINUE TO BE MOSTLY CLEAR UNDER FAIR CONDITIONS. WITH GENTLE TO MODERATE CYCLONIC WINDS OCCURRING ACROSS THE BASIN...SEAS REMAIN WITHIN THE 2-4 FT RANGE. AS THE SURFACE TROUGHING DRIFTS W-NW AND WEAKENS THROUGH WED...GENTLE TO MODERATE E-SE WINDS ARE EXPECTED THROUGH FRI NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12Z GFS BLEND WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. WATER VAPOR IMAGERY SHOWS NORTHERLY UPPER LEVEL FLOW W OF 75W ON THE WESTERN PERIPHERY OF AN UPPER LEVEL LOW CENTERED NEAR 16N74W. THE REMAINDER OF THE CARIBBEAN AND TROPICAL N ATLC IS UNDER THE INFLUENCE OF S-SW FLOW ALOFT BETWEEN THE AFOREMENTIONED LOW AND A CENTRAL ATLC UPPER LEVEL RIDGE ANCHORED IN THE VICINITY OF TROPICAL STORM IAN NEAR 23N44W. THE UPPER LEVEL RIDGE AXIS EXTENDS SW TO OVER TRINIDAD AND TOBAGO AND NE VENEZUELA. LATEST SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE WESTERN CARIBBEAN IN ASSOCIATION WITH A TROPICAL WAVE ALONG 87W THAT IS EXPECTED TO MOVE INLAND ACROSS THE YUCATAN PENINSULA AND GUATEMALA BY TONIGHT. TO THE SE OF THE TROPICAL WAVE...NUMEROUS SHOWERS AND STRONG TSTMS ARE OCCURRING ACROSS THE SW CARIBBEAN GENERALLY S OF 13N FOCUSED ALONG THE MONSOON TROUGH AXIS EXTENDING FROM CENTRAL NICARAGUA TO NW COLOMBIA. WHILE FAIRLY TRANQUIL CONDITIONS ARE NOTED ACROSS THE CARIBBEAN WITH TRADES GENERALLY RANGING GENTLE TO MODERATE...SEAS REMAIN IN THE RANGE OF 3-5 FT. BY LATER IN THE PERIOD...THU AND FRI...WINDS IN THE SOUTH-CENTRAL CARIBBEAN WILL INCREASE SLIGHTLY INTO OCCASIONAL FRESH LEVELS WITH SEAS BUILDING INTO A RANGE OF 4-6 FT BEYOND THU GENERALLY S OF 15N BETWEEN 70W-78W. NWPS MODEL GUIDANCE DEPICTS THAT NE SWELL WILL CONTINUE TO PROPAGATE INTO THE FAR NE AND ERN PORTIONS OF THE TRPCL N ATLC WITH COMBINED SEA HEIGHTS IN THE RANGE OF 6-9 FT THROUGH TUE AS TROPICAL STORM IAN MOVES N AND THEN NE OF THE FORECAST WATERS. SEAS OUTSIDE THE FAR NE ZONES AREAS ARE EXPECTED TO BE IN THE RANGE OF 4-6 FT DURING THE PERIOD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. HIGH CONFIDENCE. TROPICAL STORM IAN IS EXPECTED TO REMAIN IN THE VICINITY OF 50W- 55W AS IT MOVES N-NW...THEN N-NE DURING THE NEXT COUPLE OF DAYS. MAIN IMPACT FOR THE OFFSHORE WATERS WILL BE SWELL GENERATED BY IAN THAT IS EXPECTED TO REACH 65W BY TUE AND SPREAD TO 75W BY THU. OTHERWISE...A SURFACE TROUGH IS ANALYZED ACROSS THE BAHAMAS AND ADJACENT COASTAL WATERS FROM 22N77W TO 29N75W WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING GENERALLY W OF 74W. LATEST ASCAT PASS INDICATED MODERATE E-SE WINDS ON THE SOUTHERN PERIPHERY OF A SURFACE RIDGE ANCHORED TO THE NORTH BY A 1021 MB HIGH CENTERED NEAR 33N73W. THE TROUGHING IS FORECAST TO DRIFT W-NW DURING THE NEXT 24-36 HOURS AND MOVE ACROSS THE FLORIDA PENINSULA TUE AND TUE NIGHT. SEAS REMAIN IN THE 4-6 FT RANGE W OF THE TROUGH AXIS OUTSIDE OF THE BAHAMAS AND THIS AREA WILL TRANSLATE W-NW NORTH OF THE BAHAMAS AND OFFSHORE OF THE NORTHERN FLORIDA PENINSULA BY TONIGHT INTO EARLY TUE. .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS II COLLABORATION CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER HUFFMAN. NATIONAL HURRICANE CENTER.