000 AGXX40 KNHC 280727 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 227 AM EST MON DEC 28 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 0340 UTC ASCAT PASS SHOWED 30-33 KT W-NW WINDS IN THE IMMEDIATE AREA W OF THE FRONT OVER N WATERS. STRONGER WINDS ARE BELIEVED TO LIE FARTHER S AND W BEHIND THE FRONT. BUOYS AT 5-10 METERS ELEVATION IN THE AREA ARE GENERALLY RUNNING AT 30 KT WITH GUSTS ABOVE GALE FORCE WHILE THE ELEVATED PLATFORMS ARE REPORTING SUSTAINED GALE FORCE WINDS. THE LAND-BASED OBSERVATION AT TAMPICO MEXICO REPORTED 30 KT GUSTS 45 KT. THESE OBSERVATIONS APPEAR TO BE ON TARGET WITH THE GFS FORECAST WHICH IS THE STRONGEST OF THE 00Z MODELS AND ALLOWS GALE FORCE WINDS TO PERSIST IN THE NW GULF UNTIL 15Z TODAY AND IN THE SW GULF BEGINNING AT 09Z AND ENDING BY 18Z TODAY. IN CONTRAST...THE UKMET ENDS GALES IN BOTH THE NW AND SW GULF BETWEEN 12Z AND 18Z WHILE THE WEAK ECMWF ONLY CARRIES GALE FORCE WINDS IN THE NW GULF AT 12Z THIS MORNING...NEVER GETTING WINDS ABOVE 30 KT IN THE SW GULF. THE STRONGER GFS SEEMS TO BE ON TARGET COMPARED TO THE OBSERVATIONS. IT WAS USED TO ADJUST THE FORECAST. THE FRONT IS EXPECTED TO RETREAT N AS A WARM FRONT TUE...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 ALLOW FOR MORE NORTHERLY FLOW DIRECTING COOLER AIR INTO THE SW 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 A WARMER SOLUTION BEHIND THE FRONT WITH WEAKER NORTHERLY FLOW. THE GFS IS PREFERRED FOR ADJUSTING THE EXTENDED GRIDS AS A RESULT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: BLEND OF GFS/NWPS GUIDANCE WITH PREVIOUS FORECAST. HIGH CONFIDENCE. THE PRESSURE GRADIENT BETWEEN A STRONG BERMUDA HIGH AND A STATIONARY AREA OF LOW PRESSURE OVER NORTHERN COLOMBIA SUPPORTS A TIGHT PRESSURE GRADIENT ACROSS THE REGION...PRODUCING FRESH TO STRONG WINDS OVER MUCH OF THE AREA AND WINDS AT OR NEAR GALE FORCE WINDS IN THE S CENTRAL CARIBBEAN NEAR THE COAST OF COLOMBIA. THE GFS SHOWS GALE WARNINGS ENDING AT 09Z TODAY AND RETURNING ON TUE EVENING. THE USUALLY STRONGER GFS IS GENERALLY RELIABLE IN SUCH PATTERNS. IN THIS CASE...THE GFS APPEARS UNDERDONE WITH THE EXPANSE OF THE 30-35 KT WINDS IN THE S CENTRAL GULF WHEN COMPARED TO THE LATEST SCATTEROMETER DATA. BELIEVE THE GALE WILL PERSIST SLIGHTLY LONGER AS A RESULT. THE FORECAST WILL REFLECT THE GALE ENDING AT 12Z. THE BRIEF LULL FORECAST IN THE GALE WARNING IS ATTRIBUTABLE TO THE EASTWARD SHIFTING OF THE SUBTROPICAL RIDGE N OF THE AREA WHICH SHOULD CONTINUE THROUGH TUE AS THE COLD FRONT IN THE GULF OF MEXICO PROGRESSES EASTWARD. BY TUE EVENING...THE RIDGE SHOULD BUILD 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. FRESH TO STRONG TRADE WINDS IN THE NW CARIBBEAN ARE EXPECTED TO SHRINK IN AREA TODAY AS THE GULF OF MEXICO COLD FRONT APPROACHES. LOOK FOR WINDS TO PULSE TO A FRESH TO STRONG BREEZE IN THE EVENING AND EARLY MORNING HOURS THROUGH THU NIGHT BEFORE THE APPROACHING COLD FRONT PUSHES THE CENTRAL ATLC RIDGE AWAY FROM THE AREA...WEAKENING THE PRESSURE GRADIENT AND THE WINDS HERE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: BLEND OF GFS/NWPS GUIDANCE WITH PREVIOUS FORECAST. MEDIUM CONFIDENCE. HIGH PRESSURE HAS WEAKENED AND SHIFTED SOUTHEAST OF BERMUDA IN RESPONSE TO THE APPROACHING GULF OF MEXICO COLD FRONT AND ANOTHER FRONT IN THE CENTRAL ATLC. THE AREA OF FRESH TO STRONG EASTERLY TRADES THAT HAD SPANNED ACROSS MUCH OF THE AREA S OF 23N BETWEEN 60W-77W YESTERDAY HAS SHRUNK TO THE AREA NEAR THE N COAST OF HISPANIOLA AND THE ATLC APPROACHES TO THE WINDWARD PASSAGE SINCE THE DRIVING HIGH PRESSURE HAS WEAKENED. THE GFS FORECAST APPEARS REASONABLE OVERALL. THESE CONDITIONS ARE EXPECTED TO PERSIST UNTIL EARLY FRI BEFORE DIMINISHING. AS STATED IN THE GULF OF MEXICO SECTION...THE GFS WAS PREFERRED FOR ADJUSTING THE FORECAST FOR THE FRONT IN THE GULF OF MEXICO IN THE EXTENDED RANGE AS IT MOVES EASTWARD. THIS COLD FRONT IS EXPECTED TO REACH THE FAR NW WATERS THU EVENING AND QUICKLY SHIFT THE SUBTROPICAL RIDGE EASTWARD AWAY FROM THE AREA. THE GFS IS THE STRONGEST OF THE MODELS WITH THE WINDS BEHIND THE FRONT...SHOWING A BRIEF BURST OF FRESH TO STRONG NW WINDS FRI EVENING OFFSHORE THE COAST OF NE FLORIDA. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ011...NW GULF INCLUDING STETSON BANK... GALE WARNING EARLY TODAY. .GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W... GALE WARNING EARLY TODAY. GALE CONDITIONS POSSIBLE FRI NIGHT. .GMZ023...SW GULF S OF 22N W OF 94W... GALE WARNING EARLY TODAY INTO TODAY. GALE CONDITIONS POSSIBLE FRI NIGHT. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING EARLY TODAY. GALE WARNING TUE NIGHT. GALE CONDITIONS POSSIBLE TUE NIGHT INTO FRI NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.