000 AGXX40 KNHC 301733 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 133 PM EDT FRI OCT 30 2015 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. 12Z MODEL UPDATE... THE BIGGEST CHANGES LIE IN THE GULF OF MEXICO. A RECENT WINDSAT PASS SHOWS 30 KT RETURN FLOW IS ALREADY IN PLACE IN THE NW GULF OF MEXICO...ABOUT 6 HOURS AHEAD OF THE PREVIOUS FORECAST. ADJUSTMENTS WERE MADE ACCORDINGLY. THE 12Z GFS HAS BACKED OFF ON GALE FORCE WINDS THIS EVENING IN THE NW GULF. THIS IS IS LINE WITH THE PREVIOUS THINKING AND THE MODEL CONSENSUS. THE GFS HAS TRENDED SLIGHTLY SLOWER WITH THE COLD FRONT AND IS NOW SIMILAR WITH THE TIMING OF THE COLD FRONT PASSING E THROUGH THE CENTRAL GULF COAST TO THE 00Z ECMWF. FARTHER S...THE 12Z GFS CONTINUES TO CAP WINDS AT 30 KT IN THE SW GULF OF MEXICO...WITH THE HIGHEST WINDS SEEN 18Z SUN WHEN THE 00Z ECMWF SHOWS GALE FORCE WINDS. THE 15Z SREFS ONLY SHOW A 5-10 PERCENT CHANCE OF GALES AT THAT TIME. THE SREFS SHOW THE GREATEST CHANCE OF GALES OCCURRING AROUND 00Z MON. CONFIDENCE REMAINS LOW IN THE GALE WARNING. THE TIMING WAS NOT CHANGED BASED ON THIS NEW GUIDANCE. --------------------------------------------------------------- 06Z MODEL DISCUSSION... ...GULF OF MEXICO... MODEL PREFERENCE: LATEST GFS USED TO ADJUST THE PREVIOUS/OFFICIAL FORECAST. LATEST TAFB-NWPS FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE GFS CONTINUES TO BE ON THE FASTER/WEAKER END OF THE GLOBAL GUIDANCE WITH THE WEAKENING UPPER LOW PULLING E-NE OUT OF THE SOUTHERN PLAINS THIS WEEKEND. HOWEVER...THE GLOBAL MODELS ARE NOW IN BETTER AGREEMENT ON THE TIMING AND THE GEFS MEAN IS WEIGHTED TOWARD A FASTER SOLUTION THAN THE OPERATIONAL RUN. AT THE SURFACE...BOTH THE GFS AND ECMWF HAVE TRENDED STRONGER WITH THE RETURN FLOW IN THE NW GULF TONIGHT. THE GFS AND ECMWF CARRY 30 KT S-SE WINDS THIS EVENING THROUGH EARLY TOMORROW...WITH THE GFS SHOWING GALE CONDITIONS BRIEFLY THIS EVENING. THE GFS IS THE ONLY MODEL TO SHOW GALE HERE...SO HEDGE STRONGER BY FORECASTING 30 KT...BUT DID NOT BITE ON THE GALE. THE MODELS HAVE TRENDED STRONGER WITH THE WINDS BEHIND THE FRONT OVER THE SW GULF COMPARED TO RUNS FROM YESTERDAY. THE ECMWF AND CMC SHOW GALE FORCE WINDS HERE AT 18Z SUN...BUT THE GFS DOES NOT. CONFIDENCE IS LOW THAT WINDS WILL GET TO GALE FORCE AS THE MODELS AGREE ON THE POSITIVELY TILTED MID- TO UPPER-LEVEL RIDGE STAYING ENTRENCHED OVER THE SW GULF...LIMITING THE SURGE OF COOLER NORTHERLY FLOW TO THE LOWEST LEVELS. THE SREFS SHOW SOME SUPPORT FOR THE GALE. FOR NOW...DO NOT WANT TO STRAY FROM CONTINUITY. GALE CONDITIONS ARE FORECAST S OF 20N W OF 95W AT 18Z SUN AND 00Z MON BEFORE QUICKLY DIMINISHING. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS USED TO ADJUST THE PREVIOUS/OFFICIAL FORECAST. LATEST TAFB-NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. BUILDING HIGH PRES OVER THE CENTRAL ATLC ALLOWED TRADES TO BUILD TO A FRESH TO STRONG BREEZE THIS MORNING WITH THE ASSISTANCE OF NOCTURNAL DRAINAGE FLOW ALONG THE COAST OF COLOMBIA. THIS WAS SEEN BY THE 1152 UTC RAPIDSCAT PASS. THE SAME PATTERN SHOULD BE IN PLACE TONIGHT. THE HIGH WILL QUICKLY SHIFT E UNDER THE INFLUENCE OF A PROGRESSIVE NORTHERN STREAM. WINDS WILL GRADUALLY DIMINISH TO A GENTLE TO MODERATE BREEZE THROUGH THE WEEKEND AS A RESULT. THE MODELS ARE IN REASONABLE AGREEMENT ON THIS SCENARIO...SO THE GFS WAS USED TO ADJUST THE PREVIOUS FORECAST. A NEW BATCH OF LONG PERIOD NE SWELL HAS REACHED THE TROPICAL N ATLANTIC WATERS WITH SEAS TO AROUND 6-8 FT EXPECTED TO LINGER THROUGH THE WEEKEND BEFORE SUBSIDING. THE NWPS WAS USED TO ADJUST THE SEAS HERE. ..SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS USED TO ADJUST THE PREVIOUS/OFFICIAL FORECAST. LATEST TAFB-NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. A WEAK COLD FRONT WAS ANALYZED FROM 31N70W THROUGH THE NW BAHAMAS AND INTO THE FLORIDA KEYS. A SECOND COLD FRONT WAS ANALYZED ACROSS THE FAR NW WATERS. BOTH OF THESE FRONTS ARE WEAK AND OF LITTLE CONSEQUENCE TO THE SENSIBLE WEATHER AND SEAS ASIDE FROM SOME SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS PRIMARILY OVER AND E OF ABACO. WIND AND SEAS WILL REMAIN WELL BELOW THE ADVISORY CRITERIA OF 20-25 KT AND 8 FT...RESPECTIVELY...OVER THE AREA N OF 22N. BY SUN...HIGH PRES BUILDING FROM THE N WILL BRING AN INCREASE OF THE TRADE WINDS. A FRESH TO STRONG BREEZE WILL BE POSSIBLE ALONG THE N COAST OF HISPANIOLA AS A RESULT. THE MODELS DIFFER WITH THE TIMING OF A COLD FRONT EXPECTED TO MOVE INTO NW WATERS MON NIGHT OR TUE. THE GFS IS FASTER THAN THE ECMWF. THE GFS CARRIES THE FRONT INTO NW WATERS MON EVENING WITH 15 KT WINDS BEHIND IT. THE ECMWF CARRIES A SLIGHTLY WEAKER FRONT INTO THE AREA TUE MORNING. THE GFS CONTINUES TO BE ON THE FAST END OF THE GUIDANCE WITH THIS SYSTEM AS IT MOVES FROM THE SOUTHERN PLAINS E-NE THROUGH THE MID-ATLANTIC. A COMPROMISE SOLUTION IS PROBABLY BEST FOR NOW THIS FAR IN THE FORECAST PERIOD. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... GALE CONDITIONS POSSIBLE LATE SUN AND SUN EVENING S OF 20N W OF 95W. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 SCHAUER. NATIONAL HURRICANE CENTER.