000 AGXX40 KNHC 291707 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 107 PM EDT THU OCT 29 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. ...GULF OF MEXICO... MODEL PREFERENCE: GLOBAL MODEL BLEND USED TO ADJUST THE PREVIOUS/OFFICIAL FORECAST. LATEST NWPS FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. GREATEST UNCERTAINTY CONTINUES TO LIE WITH THE FORECAST FOR THE DEEP-LAYERED TROUGH EXPECTED TO MOVE THROUGH THE SOUTHERN PLAINS OVER THE WEEKEND. THE GFS HAS BEEN ON THE FASTER/WEAKER END OF THE GLOBAL GUIDANCE. THE GEFS AND ECMWF ENSEMBLES HINT AT A SLOWER SOLUTION...SO ADJUSTMENTS WERE MADE TOWARD THE SLOWER CONSENSUS. THE BIGGEST CHANGE TO THE FORECAST CALLED FOR THE 20-25 KT RETURN FLOW IN THE NW GULF AHEAD OF THE SLOWER COLD FRONT TO EXTEND SLIGHTLY LATER INTO SAT. IN THE SW GULF...THE ECMWF WAS WEAKER THAN THE GFS WITH THE N-NW WINDS BEHIND THE FRONT NEAR THE COAST SUN. THE GFS HAS WINDS TO NEAR GALE FORCE. THE NAVGEM AND UKMET AGREE WITH THE WEAKER ECMWF. THERE IS GENERAL AGREEMENT IN THE MODELS TO HOLD THE POSITIVELY TILTED RIDGE AXIS FROM THE SW GULF THROUGH CENTRAL FLORIDA IN PLACE...PREVENTING DEEP-LAYERED TROUGHING FROM SWINGING THROUGH THIS REGION. ADJUSTMENTS WERE MADE HERE TOWARD THESE WEAKER SOLUTIONS. ...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 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. THE SAME PATTERN SHOULD BE IN PLACE TONIGHT. THE HIGH WILL QUICKLY SHIFT E UNDER THE INFLUENCE OF A PROGRESSIVE NORTHERN STREAM. WINDS WILL GENERALLY DIMINISH TO A GENTLE TO MODERATE BREEZE FRI 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 SHOULD REACH THE TROPICAL N ATLANTIC WATERS TONIGHT INTO FRI...BUILDING SEAS TO AROUND 6-8 FT FRI THROUGH THE WEEKEND BEFORE SUBSIDING. THE NWPS WAS USED TO ADJUST THE SEAS HERE. ..SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL BLEND USED TO ADJUST THE PREVIOUS/OFFICIAL FORECAST. LATEST NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. A WEAK COLD FRONT WAS ANALYZED FROM 31N77W TO HOBE SOUND FLORIDA. A FRESH SOUTHERLY BREEZE PERSISTS AHEAD OF THE FRONT N OF 27N...BUT THESE WINDS SHOULD SHIFT N OF THE AREA OVERNIGHT. THIS FRONT WILL REACH FROM 31N70W TO THE FLORIDA KEYS FRI MORNING BEFORE BEING OVERTAKEN BY A SECOND COLD FRONT. THE SECOND COLD FRONT WILL MOVE INTO NW WATERS FRI MORNING...WEAKEN AS IT MOVES THROUGH BERMUDA AND NORTHERN BAHAMAS BY SAT MORNING AND DISSIPATE LATE SAT. THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THIS PROGRESSIVE SCENARIO...BUT SINCE THE GFS WAS CONSIDERED TOO PROGRESSIVE UPSTREAM IN THE GULF OF MEXICO...HESITATE TO USE ONLY ITS SOLUTION TO ADJUST THE FORECAST. WINDS WEAKEN AND SEAS SUBSIDE FROM THU THROUGH SAT AS THE FRONT WEAKENS AND EVENTUALLY DISSIPATES. BY SUN...HIGH PRES BUILDING FROM THE N WILL BRING AN INCREASE OF THE TRADE WINDS S OF 23N. THE GFS SHOWS A NEW COLD FRONT MOVING INTO FAR NW WATERS MON...BUT THE OTHER MODELS AND ENSEMBLES ARE SLOWER. LATEST GRIDS SLOW DOWN THE TIMING OF THIS FRONT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 SCHAUER. NATIONAL HURRICANE CENTER.