000 AGXX40 KNHC 140754 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 354 AM EDT WED SEP 14 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: 00Z GFS BLEND WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. A HIGH PRES RIDGE OVER THE SOUTHERN UNITED STATES IS MAINTAINING GENTLE TO MODERATE WINDS OVER THE GULF. WEAK SURFACE LOW PRES OF 1012 MB IS CENTERED UNDER AN UPPER-LEVEL TROUGH OVER THE CENTRAL GULF NEAR 25N90W. A TROUGH EXTENDS NW FROM THE LOW TO THE FLORIDA COAST NEAR 27N82W. CURRENT BUOY READINGS AND RECENT ALTIMETER DATA SHOW SEAS IN THE RANGE OF 1-3 FT...EXCEPT FOR AN AREA OF 3-4 FT SEAS N OF 26N BETWEEN 85W AND 97W. A NARROW UPPER LEVEL TROUGH STRETCHES FROM THE FLORIDA BIG BEND SW TO NEAR 25N86W AND SE TO THE NE YUCATAN PENINSULA. INSTABILITY ASSOCIATED WITH THIS TROUGH CONTINUES TO TRIGGER SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE ERN HALF OF THE GULF...AND OVER PORTIONS OF THE E CNTRL GULF. THIS ACTIVITY IS EXPECTED TO PERSIST THROUGH THU. THE WEAK CENTRAL GULF LOW IS FORECAST TO WEAKEN TO A TROUGH LATE TONIGHT...AND SLOWLY MOVE WESTWARD REACHING THE ERN PORTION OF THE WRN GULF BY THU NIGHT. THE 3-4 FT SEAS ARE FORECAST TO SUBSIDE TO 2-3 FT TONIGHT...OTHERWISE LITTLE CHANGE IS EXPECTED IN WINDS AND SEAS ACROSS THE BASIN THROUGH SUN NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLEND WITH PREVIOUS OFFICIAL. HIGH CONFIDENCE. A WEAK PRES PATTERN IS ALSO PRESENT ACROSS THE CARIBBEAN AND TRPCL N ATLC PER LATEST SURFACE ANALYSIS. THE WEAK PRES PATTERN IS MAINLY A RESULT OF TROPICAL STORM IAN WELL NE OF THE AREA. LATEST ASCAT DATA AND BUOY OBSERVATIONS INDICATE GENERALLY GENTLE TO MODERATE NE-E WINDS THROUGHOUT...EXCEPT FOR MAINLY MODERATE E-SE WINDS IN THE GULF OF HONDURAS AND ALONG THE COAST OF COLOMBIA. SEAS ARE IN THE RANGE OF 3-4 FT IN THE CARIBBEAN ...EXCEPT FOR LOWER SEAS OF 2-3 FT N OF 17N W OF 62W...AND ALSO S OF 11N W OF 75W. SEAS IN THE TRPCL N ATLC ARE IN THE 4-5 FT RANGE S OF 15N...AND 5-7 FT N OF 15N DUE TO A NE TO E SWELL. WAVE MODEL GUIDANCE SHOW SWELL ASSOCIATED WITH IAN THAT ARE PROPAGATING INTO THE THE NRN HALF OF THE TRPCL N ATLC GRADUALLY DIMINISHING THROUGH THIS EVENING AS IAN CONTINUES TO PULL NORTHWARD AWAY FROM THE TRPCL N ATLC. THE GUIDANCE IS SUGGESTING THAT COMBINED SEAS IN THE TRPCL N ATLC WILL LOWER TO 3-4 FT ON THU. WATER VAPOR IMAGERY INDICATES AMPLE DEEP LAYER MOISTURE PRESENT OVER THE MUCH OF THE NW AN N CENTRAL CARIBBEAN. SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED IN THOSE AREAS OF THE CARIBBEAN. A VERY ACTIVE ERN PACIFIC MONSOON TROUGH STRETCHES E ACROSS THE SW CARIBBEAN SEA. THE ASSOCIATED LOW-LEVEL CONVERGENCE IS HELPING TO AID IN THE DEVELOPMENT OF SCATTERED TSTM ACTIVITY TO THE S OF 13N AND W OF 78W. THIS ACTIVITY IS EXPECTED TO PERSIST THROUGH THE PERIOD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. HIGH CONFIDENCE. TROPICAL STORM JULIA FORMED AT 03Z LAST NIGHT...AND IS PRESENTLY INLAND FAR SE GEORGIA AS OF 09Z WITH MAXIMUM WINDS OF 35 KT GUSTS TO 45 KT. NUMEROUS SQUALLS AND TSTMS ARE OBSERVED ON SATELLITE IMAGERY AND NWS RADAR ANIMATION TO BE CONFINED OVER THE NW WATERS THIS MORNING. LATEST ASCAT DATA SHOWED SE-S TROPICAL STORM FORCE WINDS WITHIN ABOUT 60 NM OF THE NE FL COAST. AS JULIA MOVES FARTHER N TODAY...THESE WINDS WILL THEN BEGIN TO RELAX. SEAS OF 6-8 FT WITH THIS WINDS WILL THEN LOWER TO 4-7 FT TODAY. THE ASCAT PASS FROM 0158Z ALSO REVEALED SE-S WINDS OF 20-30 KT ELSEWHERE N OF 28N W OF 78W. THESE WINDS ARE EXPECTED TO DIMINISH TO 10-15 KT LATER THIS MORNING WITH SEAS OF 3-5 FT. OTHERWISE...THE FORECAST WILL HAVER VERY LITTLE IN THE WAY OF CHANGES. RELATIVELY WEAK HIGH PRES WILL CONTINUE TO CONTROL THE WIND FLOW THROUGHOUT THE BASIN DURING THE PERIOD WITH THE ASSOCIATED GRADIENT ALLOWING FOR GENTLE TO MODERATE E-SE WINDS...EXCEPT FOR THE WATERS BETWEEN THE SE BAHAMAS AND HISPANIOLA WHERE FRESH NE-E WINDS ARE EXPECTED. .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 AGUIRRE. NATIONAL HURRICANE CENTER.