000 AGXX40 KNHC 170750 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 250 AM EST TUE FEB 17 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: 00Z GFS USED TO ADJUST WINDS. 00Z NWPS USED TO ADJUST WAVES. MEDIUM CONFIDENCE. INITIALLY...THE 00Z ECMWF AND GFS HAVE COME INTO REASONABLE AGREEMENT WITH THE FRONT CURRENTLY OVER THE NW GULF. THE HIGHER RESOLUTION GFS DID A BETTER JOB DEPICTING THE WINDS BEHIND THE FRONT MON EVENING...WITH THE 00Z GFS AGREEING WITH THE 30 KT OBSERVATIONS...BUT NEITHER MODEL IS STRONG ENOUGH WITH THE SW FLOW AHEAD OF THE FRONT COMPARED TO ASCAT. THE MWW3...NWPS...AND EC WAVE GUIDANCE ARE ALL 1-3 FT TOO LOW WITH SEAS BEHIND THE FRONT COMPARED TO A RECENT ALTIMETER PASS THAT SHOWED AN AREA OF 8-10 FT SEAS ON THE BOUNDARY OF THE COASTAL WATERS AND THE NW GULF OFFSHORE ZONE S OF 27.5N. SEAS WERE BUMPED UP IN THE AREA OF HIGHEST WINDS ACCORDINGLY. BOTH MODELS PLACE THE FRONT FROM NEAR SARASOTA BAY TO THE SW GULF BY THIS EVENING AND SEND THE FRONT SE OF THE AREA WED MORNING WHEN A REINFORCING SURGE OF COLD NORTHERLY FLOW INCREASES WINDS BEHIND THE FRONT. THE PROBLEM OF THE DAY IS WHETHER TO KEEP THE GALE WARNING NEAR THE COAST IN THE SW GULF ZONE (GMZ023) FOR WED. THE 00Z GFS AND ECMWF CAP WINDS AT 30 KT HERE AFTER THE FRONTAL PASSAGE THIS EVENING AND AFTER THE REINFORCING SURE OF COLD AIR MOVES IN WED. THE 20 KM NAM...WHICH HAD SHOWN A GALE THIS TIME YESTERDAY...HAS ALSO BACKED OFF TO 30 KT. HOWEVER...THE 21Z SREF CONTINUES TO SHOW UP TO A 30 PERCENT CHANCE OF GALES BETWEEN 12Z AND 21Z WED. IT WILL LIKELY BE A MARGINAL EVENT OVER A SMALL AREA...BUT IT SEEMS PRUDENT TO ERR ON THE SIDE OF CAUTION AND KEEP THE GALE WARNING UP GIVEN THE SREF SUPPORT AND THE CURRENT STRENGTH OF THE FRONT. OTHERWISE...THE GFS LOOKS REASONABLE ACROSS THE GULF AND SUGGESTS LITTLE CHANGE TO THE PREVIOUS FORECAST...ALLOWING THE NWPS TO BE A GOOD CHOICE FOR ADJUSTING THE WAVES. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS USED TO ADJUST WINDS. 00Z NWPS USED TO ADJUST WAVES. HIGH CONFIDENCE. THE TIGHT PRESSURE GRADIENT BETWEEN A RIDGE EXTENDING THROUGH THE STRAITS OF FLORIDA LOW PRES OVER COLOMBIA HAS BROUGHT GALE WINDS TO THE COAST OF COLOMBIA THIS MORNING ACCORDING TO THE 0246 UTC ASCAT-B PASS. GALE CONDITIONS ARE EXPECTED TO CONTINUE OFF THE COAST OF COLOMBIA UNTIL JUST AFTER SUNRISE. THE RECENT SCATTEROMETER PASSES ALSO SHOW FRESH TO STRONG NE WINDS IN THE WINDWARD PASSAGE AND S OF HISPANIOLA. THE QUARTER DEGREE 00Z GFS IS DOING A GOOD JOB DEPICTING THE CONDITIONS OFF COLOMBIA AND HISPANIOLA...BUT DOES NOT SHOW 25 KT WINDS IN THE WINDWARD PASSAGE. WINDS WILL BE BUMPED UP FOR THE MORNING HOURS TODAY...BUT THE WIND DIRECTION SHOULD SHIFT...DIMINISHING THE FUNNELING THROUGH THE PASSAGE LATER TODAY. THE FORECAST CALLS FOR THE RIDGE TO THE N TO BE FORCED EASTWARD TODAY AND TONIGHT...LESSENING THE PRESSURE GRADIENT ACROSS THE CENTRAL CARIBBEAN AND DIMINISHING WINDS. AN EARLIER ALTIMETER PASS FROM THE SW DOMINICAN REPUBLIC TO THE N CENTRAL COLOMBIAN COAST SHOWED SEAS TO 11 FT AROUND 15N-16N. THE MWW3 WAS A FOOT OR TWO TOO LOW HERE. THE NWPS WAS SLIGHTLY BETTER INITIALLY AND SEEMS REASONABLE FOR ADJUSTING THE FORECAST EARLY IN THE PERIOD. A NEW FRONT WILL MOVE INTO THE NW CARIBBEAN WED MORNING. BY THU MORNING...BOTH THE GFS AND ECMWF EXTEND THE FRONT FROM EASTERN CUBA TO EASTERN HONDURAS. BY THU EVENING...THE FRONT SHOULD MOVE THROUGH THE WINDWARD PASSAGE. A GALE MAY BE POSSIBLE IN THE WINDWARD PASSAGE THU EVENING BEHIND THE FRONT AFTER IT IS INVIGORATED BY A SURGE OF COLDER AIR. THE QUARTER DEGREE GFS SHOWS 30 KT WINDS HERE AT THAT TIME. WILL HOLD OFF ON A GALE HERE FOR NOW. GIVEN THE STRENGTH OF THE ARCTIC AIRMASS EXPECTED TO DRIVE THE FRONT...WILL GIVE THE EDGE TO THE GFS WHICH HAS A SLIGHTLY STRONGER FORECAST. THE 00Z GFS WILL BE USED TO ADJUST THE PREVIOUS FORECAST HERE THROUGH SAT NIGHT. THE NWPS SEEMS REASONABLE TONIGHT THROUGH FRI NIGHT. GALE CONDITIONS ARE EXPECTED TO RETURN TO THE COAST OF COLOMBIA EARLY SAT MORNING AS HIGH PRES MOVES IN BEHIND THE COLD FRONT...WITH WINDS TO 40 KT POSSIBLE BY LATE SAT NIGHT. THE NWPS BECOMES FASTER TO SUBSIDE THE SEAS IN THE CENTRAL CARIBBEAN THAN THE MWW3. WITH THE STRONG HIGH PRESSURE AND STRONG WINDS PREFERRED...WILL BUMP SEAS UP CLOSER TO THE MWW3 ON SAT AND SAT NIGHT. THIS ALLOWS FOR A SIZABLE AREA OF 12 FT SEAS BY SAT NIGHT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS USED TO ADJUST WINDS. 00Z EC WAVE USED TO ADJUST WAVES. MEDIUM CONFIDENCE. THE ASCAT-B PASS FROM JUST BEFORE 03Z AND RECENT BUOY DATA SHOW S-SW WINDS ARE STRONGER OFF THE N FLORIDA COAST THAN THE GFS AND ECMWF ARE ADVERTISING. SHIP DPLE NEAR 31N79.5W AT 06Z REPORTED GALE FORCE WINDS. THE 00Z GEFS SHOWS A CHANCE OF GALE HOVERING JUST N OF THE AREA FROM 06Z THROUGH 18Z BEFORE FALLING OFF THE EVENING BEFORE THE AFOREMENTIONED SURGE OF ARCTIC AIR INVIGORATES THE FRONT WED MORNING. GALE CONDITIONS SHOULD THEN RETURN AHEAD OF THE FRONT DURING THE DAY WED...AS THE GEFS ENSEMBLES AND QUARTER DEGREE 00Z GFS SUGGEST. WINDS AND SEAS WERE ADJUSTED UP OVER THE FIRST FEW PERIODS TO MATCH THE OBSERVATIONS. THE GFS WAS USED TO ADJUST THE FORECAST THEREAFTER. IT IS IN REASONABLE AGREEMENT ON THE TIMING OF THE FRONT WITH THE ECMWF...WITH BOTH MODELS CARRYING IT FROM NEAR BERMUDA TO EASTERN CUBA THU MORNING...BUT ITS HIGHER RESOLUTION OUTPUT IS PREFERRED FOR THE AREAS OF STRONGER WINDS. THE MWW3 CONTINUES TO BE 3-6 FT TOO SMALL WITH THE LARGE NW SWELLS OVER THE ATLC WATERS. SINCE THE NWPS BOUNDARY CONDITIONS COME FROM THE MWW3...IT IS ALSO TOO LOW WITH THE SWELL. IN ADDITION...THE ECMWF IS CLOSER TO THE MODEL CONSENSUS IN THE EXTENDED RANGE WITH THE WEATHER PATTERN IN THE N ATLC. DESPITE A STRONGER LOW PRES SYSTEM IN THE GFS PROVIDING SWELL TO OUR AREA...IT CONTINUES TO BE LOWER THAN THE EC WAVE WITH SEAS. THE EC WAVE WAS USED TO ADJUST THE WAVES. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... GALE WARNING WED. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING EARLY TODAY INTO TODAY. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... GALE WARNING TODAY. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... GALE WARNING TODAY. GALE WARNING WED. .AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W... GALE WARNING WED. $$ *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.