000 AGXX40 KNHC 290733 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 233 AM EST TUE DEC 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: BLEND OF GFS/NWPS WITH PREVIOUS FORECAST. MEDIUM CONFIDENCE. THE 0318Z AND 0412Z ASCAT PASSES SHOWED WINDS HAVE DIMINISHED BELOW A FRESH TO STRONG BREEZE IN THE SW GULF OF MEXICO. THE GLOBAL MODELS ALL SHOW WINDS BELOW ADVISORY CRITERIA BY 06Z. AN 06Z OBSERVATION AT BUOY 42055 SHOWED SEAS STILL AT 9 FT. THE MWW3 WAS 2 FT LOWER...THE NWPS WAS 1 FT LOWER...AND THE UKMET WAVE AND EC WAVE MATCHED THE OBSERVATION. WHILE THE NWPS WAS PREFERRED OVERALL FOR ADJUSTING THE SEAS...THE EC WAVE WAS USED FOR THE FIRST FEW PERIOD WILL THIS RESIDUAL SWELL. ON THE LEADING EDGE OF THE FRONT...ASCAT PASS FROM 0318Z SHOWS 20-25 KT SOUTHERLY WINDS WITHIN 120 NM S-SW OF APALACHICOLA. THE MODELS AGREE ON DIMINISHING THESE WINDS QUICKLY BETWEEN 00Z-06Z. WINDS ARE BELIEVED TO BE BELOW ADVISORY CRITERIA HERE NOW. BUOYS 42039 AND 42036 AHEAD OF THE FRONT DID NOT REPORT WINDS OVER 16 KT OR SEAS OVER 6 FT AT 06Z. THE FRONT IS EXPECTED TO RETREAT NW AS A WARM FRONT TODAY...WITH A WEAK PUSH OF COOLER AIR EXPECTED TO MOVE THE FRONT SOUTHEASTWARD AGAIN WED AND THU. THE MODELS ARE IN GOOD AGREEMENT ON THE POSITION OF THE FRONT...BUT THE UKMET AND ECMWF CONTINUE TO ALLOW FOR MORE NORTHERLY FLOW DIRECTING COOLER AIR INTO THE W CENTRAL GULF WHILE THE GFS KEEPS THE COLDER AIR BOTTLED UP FARTHER N WED AND THU. THE MODELS AGREE ON AN UPPER PATTERN THAT MAINTAINS A PERSISTENT RIDGE ACROSS THE SW GULF WHICH WOULD APPEAR TO FAVOR LESS NORTHERLY FLOW ALONG THE COAST OF VERACRUZ THROUGH THU. THE GFS IS PREFERRED FOR ADJUSTING THE EXTENDED GRIDS AS A RESULT. BY FRI...THE MODELS AGREE ON GRADUALLY LOWERING HEIGHTS ON THE LEADING EDGE OF A POSITIVELY TILTED UPPER TROUGH STRETCHED MERIDIONALLY ACROSS THE UNITED STATES. THIS ALLOWS MORE COLD AIR TO SEEP IN BEHIND THE PERSISTENT FRONT. THE GFS SHOWS GALES IN THE WESTERN GULF FROM 00Z SAT THROUGH 06Z SUN. THE ECMWF ONLY SHOWS GALES IN THE SW GULF 18Z SAT THROUGH 12Z SUN. THE UKMET SHOWS GALES 18Z FRI THROUGH 06Z SUN. THE ECMWF LOOKS WEAK WITH THE WIND GIVEN THE PATTERN WHILE THE GFS AND UKMET ARE RELATIVELY SIMILAR. AGAIN...THE GFS SEEMS REASONABLE FOR ADJUSTING THE GRIDS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: BLEND OF GFS/NWPS GUIDANCE WITH PREVIOUS FORECAST. MEDIUM CONFIDENCE. THE 0228 UTC ASCAT-B PASS SHOWED 30-33 KT TRADE WINDS IN THE GULF OF VENEZUELA AND OFF THE NE COAST OF COLOMBIA. THIS WAS STRONGER THAN THE GLOBAL MODELS BY 5-10 KT. DESPITE A WEAKENED SUBTROPICAL HIGH...THE PRESSURE GRADIENT HAS REMAINED STRONG BECAUSE THE HIGH POSITION HAS SHIFTED S. THE FORECAST CALLS FOR THE RIDGE TO STRENGTHEN THROUGH WED. WIND GRIDS WILL BE BUMPED UP SOME DURING THE DIURNAL PEAK OF TOPOGRAPHIC ENHANCEMENT OFF COLOMBIA. THIS WILL RESULT IN A GALE WARNING THIS MORNING OFF COLOMBIA AS WELL AS IN THE GULF OF VENEZUELA. WINDS SHOULD BRIEFLY DIP BELOW 34 KT AFTER SUNRISE THROUGH THE AFTERNOON...BUT THE GFS SHOWS THE WINDS RETURNING BY SUNSET AS THE RIDGE BUILDS BACK ACROSS THE SW N ATLC AND EASTERN GULF OF MEXICO...FORCING THE FRONT IN THE GULF NORTHWARD AS A WARM FRONT BEFORE IT HAS A CHANCE TO REACH THE CARIBBEAN. GALE CONDITIONS SHOULD DIMINISH AFTER SUNRISE ON FRI AS THE LEADING EDGE OF THE GULF OF MEXICO COLD FRONT MOVES INTO THE SW N ATLC AND PUSHES THE RIDGE EASTWARD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: BLEND OF GFS/NWPS GUIDANCE WITH PREVIOUS FORECAST. MEDIUM CONFIDENCE. THE GFS APPEARS WELL INITIALIZED WITH THE STRONGEST WINDS OVER THE FORECAST AREA WHICH LIE N OF HISPANIOLA. THE FRESH TO STRONG TRADE WINDS NEAR THE N COAST OF HISPANIOLA AND THE ATLC APPROACHES TO THE WINDWARD PASSAGE ARE THE RESULT OF THE PRESSURE GRADIENT BETWEEN WEAKENING HIGH PRESSURE THAT HAS SETTLED NEAR 29N62W AND LOWER PRESSURE OVER THE SOUTHERN CARIBBEAN. THESE CONDITIONS ARE EXPECTED TO PERSIST UNTIL EARLY FRI BEFORE DIMINISHING AS THE FRONT IN THE GULF OF MEXICO MOVES EASTWARD INTO THE NW PORTION OF THE ZONE...PUSHING THE SUBTROPICAL RIDGE EASTWARD. THE GFS IS PREFERRED WITH THE FRONTAL TIMING HERE. THE GFS AND UKMET ARE FASTER WITH THE FRONT AND STRONGER WITH THE WIND BEHIND IT THAN THE ECMWF FRI INTO SAT. THE BIGGEST QUESTION MARK COMES OVER THE WEEKEND WHEN THE GFS DEVELOPS A STRONGER WAVE ALONG THE BOUNDARY THAT SLOWS THE PROGRESS OF THE FRONT THROUGH THE BAHAMAS AND FLORIDA. THE ECMWF AND UKMET BOTH CARRY THE WAVE...BUT THEY ARE NOT AS STRONG. THE GEFS IS EVEN MORE AMPLIFIED THAN THE OPERATIONAL GFS WITH THE WAVE AND THE EC ENS SHOWS MORE OF A WAVE THAN THE OPERATIONAL ECMWF. THE GFS SEEMS TO HAVE MORE ENSEMBLE SUPPORT...SO WILL CONTINUE TO SIDE WITH ITS SOLUTION. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W... GALE WARNING FRI NIGHT INTO SAT. .GMZ023...SW GULF S OF 22N W OF 94W... GALE WARNING FRI NIGHT INTO SAT NIGHT. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING TONIGHT INTO FRI. .AMZ033...CARIBBEAN S OF 15N BETWEEN 64W AND 72W INCLUDING VENEZUELA BASIN... GALE WARNING TONIGHT INTO WED NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.