000 AGXX40 KNHC 190743 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 243 AM EST THU FEB 19 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: A BLEND OF THE 00Z GFS AND ECMWF USED TO ADJUST THE WINDS. 00Z NWPS USED TO ADJUST WAVES. MEDIUM CONFIDENCE. SCATTEROMETER PASSES SINCE 02Z SHOW THE WINDS IN THE 00Z GFS AND ECMWF ARE REASONABLY WELL INITIALIZED...WITH A STRONG N-NW BREEZE OVER THE EASTERN GULF AND WEAK WINDS AROUND HIGH PRES FOUND OVER THE NW GULF. A RECENT ALTIMETER PASS SHOWS 8-9 FT SEAS IN THE NE GULF. THE HIGHER SEAS IN THE NWPS...AND EC WAVE...ARE BETTER INITIALIZED HERE THAN THE MWW3. HOWEVER...NONE OF THE GUIDANCE CAPTURES THE 11-13 FT SEAS SEEN JUST N OF THE YUCATAN CHANNEL WHERE THE WIND IS COUNTER TO THE CURRENT. SEAS WILL BE BEEFED UP HERE TODAY WHILE THE WINDS ARE A FRESH TO STRONG N-NE BREEZE. THE 00Z GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT. THEY AGREE ON CARRYING THE STRONGEST RETURN FLOW OVER THE N GULF SAT MORNING AND THEN DIMINISH THE RETURN FLOW THROUGH SAT NIGHT. HOWEVER...THE GFS IS FASTER TO CARRY THE FRONT TO THE COAST. THE GFS HAS THE FRONT REACHING THE CENTRAL TEXAS BY 18Z SUN WHILE THE ECMWF WAITS UNTIL 06Z MON. THE UKMET IS IN BETTER AGREEMENT WITH THE SLOWER ECMWF WHILE THE GEFS AND EC ENS MEAN APPEAR TO SPLIT THE DIFFERENCE. BY MON NIGHT...THE GFS BECOMES 6 HOURS FASTER ALLOWING A SURGE OF NORTHERLY FLOW TO ACCELERATE THE FRONT COMPARED TO THE ECMWF. NEITHER MODEL ALLOWS WINDS TO REACH 30 KT BEHIND THE FRONT. CONFIDENCE IS LOWER IN THE FINE DETAILS...SO A BLEND OF THE GFS AND ECMWF SEEMS PRUDENT TO ADJUST THE WINDS. THIS IS NOT TOO FAR OFF THE PREVIOUS FORECAST...SO THE NWPS WILL BE USED TO ADJUST THE SEAS. ...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 CONSENSUS OF SHIP AND BUOY REPORTS AT 06Z SHOW N WINDS AT A STRONG BREEZE TO NEAR GALE OFF THE YUCATAN PENINSULA IN THE NW CARIBBEAN. BUOY 42056 REPORTED 10 FT SEAS. THE MWW3 WAS 2 FT TOO LOW HERE...WITH THE NWPS AND EC WAVE CLOSER TO THE OBSERVATION. THE 00Z GFS...00Z ECMWF...AND 20 KT 00Z NAM DO NOT CARRY 30 KT WINDS IN THE NW CARIBBEAN. AS HAS BEEN THE CASE WITH THIS ARCTIC AIR MASS...WINDS HAD TO BE ADJUSTED UP SLIGHTLY TO MATCH THE OBSERVATIONS. 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 AGAIN INVIGORATED BY A SURGE OF COLDER AIR. THE QUARTER DEGREE GFS SHOWS 30 KT WINDS HERE AT THAT TIME. IT IS POSSIBLE THAT WINDS WILL BRIEFLY REACH GALE FORCE BEHIND THE FRONT. HOWEVER...THE 20 KM NAM DOES NOT ALLOW WINDS TO REACH 30 KT. GIVEN THE WIND DIRECTION AND STRENGTH OF THE COLD AIR MASS...THE FUNNELING HERE BETWEEN HIGH TERRAIN SHOULD BE ENOUGH TO SUPPORT THE HIGHER END OF THE GUIDANCE SEEN IN THE GFS. WINDS WILL CONTINUE TO BE FORECAST TO REMAIN SHORT OF A GALE. THE NWPS SEEMS REASONABLE TONIGHT THROUGH MON NIGHT. GALE CONDITIONS ARE EXPECTED ALONG THE COAST OF COLOMBIA EARLY SAT MORNING AS HIGH PRES MOVES IN BEHIND THE COLD FRONT...WITH WINDS TO 40 KT POSSIBLE BY LATE SUN NIGHT AND GALE CONDITIONS EXPECTED TO PERSIST THROUGH MON NIGHT. WITH THE ECMWF AND GFS IN BETTER AGREEMENT WITH THE PROGRESSION OF THE DRIVING HIGH PRESSURE N OF THE AREA...THE HIGHER RESOLUTION GFS SHOULD BE A REASONABLE FOR ADJUSTING THE FORECAST. AS EXPLAINED BELOW...THE MWW3 HAS BEEN TOO LOW WITH LONG PERIOD SWELL IN THE ATLC. THE NWPS WAS USED TO ADJUST SEAS HERE. THE EC WAVE WAS BETTER INITIALIZED COMPARED TO ALTIMETER DATA THAT SHOWED 10-12 FT SEAS IN THE ATLC WATERS ADJACENT TO THE NE CARIBBEAN WHILE THE MWW3 WAS APPROXIMATELY 2 FT TOO LOW AND THE NWPS WAS CLOSER TO THE EC WAVE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: A BLEND OF THE 00Z GFS AND ECMWF USED TO ADJUST THE WINDS. 00Z NWPS USED TO ADJUST WAVES. MEDIUM CONFIDENCE. THE ASCAT-B PASS FROM AROUND 0210Z SHOWED W WINDS JUST BELOW GALE FORCE AHEAD OF THE REINFORCING COLD FRONT ABOUT TO MOVE OFF THE N FLORIDA COAST. THE 00Z GEFS KEEPS ANY CHANCE OF GALES JUST N OF THE AREA AT 06Z...BUT SHIPS CLOSEST TO THE AREA OF SUSPECTED STRONGEST WINDS S OF 31N ARE REPORTING 30 KT AND 32 KT. THE QUARTER DEGREE GFS WAS 5-10 KT TOO LOW WITH WINDS OBSERVED BY THE ASCAT PASS JUST N OF THE AREA. CONFIDENCE IS HIGH THAT A GALE WARNING IS WARRANTED HERE UNTIL 12Z WHEN THE PROBABILITIES IN THE 00Z GEFS DROP OFF PRECIPITOUSLY N OF THE AREA. THE REINFORCING COLD FRONT SHOULD MEET THE MAIN COLD FRONT LATER TODAY...INCREASING THE WINDS AHEAD OF IT TO GALE FORCE. A GALE WARNING IS IN EFFECT FROM 12Z TODAY TO 00Z FRI. THIS IS IN LINE WITH A SLIGHTLY BEEFED UP VERSION OF THE 00Z GFS...AND IS CONSISTENT WITH THE THINKING THAT THE MODELS HAVE NOT BEEN STRONG ENOUGH WITH THE WINDS ASSOCIATED WITH THESE ARCTIC SURGES. AS EXPLAINED IN THE GULF OF MEXICO SECTION...A BLEND OF THE GFS AND ECMWF SEEMS PRUDENT WITH THE NEXT COLD FRONT. BOTH THE GFS AND ECMWF AGREE ON THE FRONT REACHING NW WATERS MON NIGHT. BOTH MODELS AGREE ON SHIFTING THE WINDS MORE TO THE SE OVER THE NW PORTION BY SAT AFTERNOON...BUT THE ECMWF CARRIES SLIGHTLY WEAKER RETURN FLOW AHEAD OF THE FRONT THAN THE GFS. WITH CONFIDENCE LOWER IN THE FINE DETAILS...A BLEND SEEMS PRUDENT. THE NWPS APPEARS TO BE DOING A BETTER JOB WITH THE SEAS OVER SW N ATLC WATERS NOW THAT WIND IS THE PRIMARY DRIVER AS OPPOSED TO LONG PERIOD SWELL. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE CONDITIONS POSSIBLE FRI NIGHT. GALE CONDITIONS POSSIBLE SAT NIGHT. GALE CONDITIONS POSSIBLE SUN NIGHT. GALE CONDITIONS POSSIBLE MON NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... GALE WARNING EARLY TODAY. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... GALE WARNING EARLY TODAY. $$ *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.