000 AGXX40 KNHC 230759 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 259 AM EST MON DEC 23 2013 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: PREVIOUS/OFFICIAL FORECAST BLENDED WITH LATEST GFS THROUGH WED WITH THE ECMWF ADDED THU AND FRI. PREVIOUS FORECAST AND MWW3 BLEND USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE 0346Z ASCAT-A AND 0302Z ASCAT-B PASSES SHOW A LARGE AREA OF NEAR GALE FORCE WINDS W OF THE COLD FRONT AND S OF 26N. GIVEN THE LOW BIAS IN THE ASCAT...A GALE EVENT APPEARS TO BE IN PROGRESS. NONE OF THE MODELS SHOWED 10-METER WINDS THIS STRONG IN THEIR FORECASTS. HOWEVER...THE 03Z SREF CARRIED AS HIGH AS A 35 PERCENT CHANCE OF 34-KT WINDS JUST W OF THE FRONT BY 23/00Z. THIS WAS A CHANGE FROM THE LAST FEW NIGHTS OF SREF RUNS WHICH ONLY SHOWED A CHANCE OF GALES IN THE SW PORTION OF THE GULF. ADJUSTMENTS HAD TO BE MADE TO THE GALE WARNING AREA TO INCLUDE GMZ017 IN THE WARNING AND TO START IT 12 HOURS EARLY AT 23/00Z. THE 00Z GFS CONTINUES TO BE THE STRONGEST MODEL WITH THE PEAK WINDS...SHOWING WINDS TO 40 KT IN THE SW GULF. THE 00Z ECMWF NOW EXPLICITLY CARRIES A GALE INTO ZONE GMZ025 TUE MORNING. THE 00Z GEFS DOES NOT EVEN SHOW A CHANCE OF GALE FORCE WINDS UNTIL 23/18Z AND TURNS OFF THE GALE BY 24/18Z. MEANWHILE...THE 03Z SREF CONTINUES TO CARRY A 20 PERCENT CHANCE OF GALES AS LATE AS 25/00Z. THE 00Z ECMWF HAS WINDS DOWN TO 20 KT BY THEN WITH THE GFS SHOWING ONLY A VERY SMALL AREA OF 30 KT WINDS THAT LATE. THE HIGHER RESOLUTION 00Z NAM KEEPS THE GALE THROUGH 24/18Z. THIS SEEMS REASONABLE GIVEN THE TREND TOWARD A STRONGER SOLUTION. WILL EXTENDS THE GALE WARNING IN ZONES GMZ023 AND GMZ025 THROUGH 24/18Z. FRESH TO STRONG NORTHERLY WINDS WILL SPREAD ACROSS THE REMAINDER OF THE GULF BEHIND THE FRONT THROUGH TUE...GRADUALLY DIMINISHING AND TURNING MORE TO THE NE-E AS HIGH PRES SLIDES ACROSS THE CAROLINAS BY EARLY WED. MAINLY MODERATE TO LOCALLY FRESH NE-E WINDS AND 4-7 SEAS ARE EXPECTED LATE WED THROUGH FRI. LINGERING TROUGHING OVER THE WESTERN GULF COMBINED WITH BUILDING TROUGHING OVER THE BAHAMAS WILL SHIFT THE STRONGEST PRES GRADIENT INTO CENTRAL GULF WATERS THU AND FRI. WITH CONFIDENCE LOWER IN THE EXTENDED RANGE DETAILS...A BLEND OF THE ECMWF AND GFS WAS USED TO ADJUST THE FORECAST THU AND FRI. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 65W... MODEL PREFERENCE: PREVIOUS/OFFICIAL FORECAST BLENDED WITH LATEST GFS. NWPS/MWW3 BLEND USED FOR WAVE PARAMETERS. HIGH CONFIDENCE. THE 0202Z ASCAT-A AND 0258Z ASCAT-B PASSES SHOW AN AREA OF NEAR GALE FORCE WINDS WITHIN 90 NM OF THE COAST OF COLOMBIA. GIVEN THE LOW BIAS IN THE ASCAT AND THE FACT THAT THE PASSES OCCURRED PRIOR TO THE DIURNAL MAXIMUM OF WINDS ALONG THE COLOMBIAN COAST...A GALE WARNING WAS AGAIN ISSUED FOR THIS AREA. THE WARNING WILL EXPIRE AFTER 12Z WHEN THE COLD FRONT OVER THE GULF OF MEXICO SHOULD WEAKEN THE PRESSURE GRADIENT ENOUGH ACROSS THE CENTRAL CARIBBEAN TO BRING THE WINDS BACK BELOW WARNING CRITERIA. OTHERWISE...TRADE WINDS WILL DIMINISH SIGNIFICANTLY TONIGHT INTO TUE AS THE PRESSURE GRADIENT OVER THE AREA WEAKENS DUE TO COLD FRONTAL INTRUSION AND THE AMPLIFICATION OF A TROUGH MOVING INTO THE NE CARIBBEAN. WINDS WILL BE LIGHT TO MODERATE BASIN WIDE TUE...WITH SEAS DOWN TO 3-6 FT. THE GFS BRINGS THE FRONT THROUGH THE YUCATAN CHANNEL EARLY TUE NIGHT AND STALLS IT IN THE FAR NW GULF ALONG 20N UNTIL IT RETROGRADES NORTHWARD WED AS THE MENTIONED TROUGHING BUILDS OVER THE NE CARIBBEAN. THE ECMWF HAS TRENDED STRONGER WITH THE FRONT...NOW PUSHING IT INTO THE NW CARIBBEAN TUE NIGHT AND RETROGRADING IT WED AS WELL. GIVEN THE ECMWF IS TRENDING TOWARD THE GFS AND THE GFS IS DOING SLIGHTLY BETTER WITH THE CONDITIONS CURRENTLY NEAR THE COAST OF COLOMBIA...WILL USE THE GFS ALONE TO ADJUST THE FORECAST HERE. WINDS HAVE DIMINISHED TO A MODERATE BREEZE OVER THE SOUTHERN WATERS OF THE TROPICAL N ATLC AND SEAS ARE SUBSIDING TO 6-8 FT SEAS AS A BROAD TROUGH MOVES FROM SE TO NW ACROSS THE WATERS. THIS TROUGH WILL PASS UNDER A DEVELOPING UPPER LOW TUE AND WED THAT WILL AMPLIFY IT AT THE SURFACE AS IT MOVES INTO THE EASTERN CARIBBEAN. THIS WILL WEAKEN THE PRESSURE GRADIENT...WITH LIGHT TO MODERATE NE WINDS EXPECTED W OF THROUGH AXIS...AND MODERATE SE WINDS N OF 15N E OF THE TROUGH AXIS TUE THROUGH FRI. ...SW N ATLANTIC W OF 65W INCLUDING THE BAHAMAS... PREVIOUS/OFFICIAL FORECAST BLENDED WITH LATEST GFS WITH THE ECMWF ADDED WED THROUGH FRI. NWPS/MWW3 BLEND USED FOR WAVE PARAMETERS WITH EC WAVE ADDED WED THROUGH FRI. HIGH CONFIDENCE THROUGH TUE AND MEDIUM CONFIDENCE WED THROUGH FRI. THE BERMUDA HIGH CONTINUES TO DRIVE THE EASTERLY FLOW ACROSS THE AREA...WITH FRESH TO LOCALLY STRONG WINDS S OF 27N AND MODERATE TO LOCALLY FRESH N OF 27N. SEAS ARE GENERALLY 4-7 FT N OF 27N...AND 7-10 FT S OF 27N...EXCEPT 1-3 FT INSIDE THE BAHAMAS. TRADE WINDS WILL BEGIN TO DIMINISH THIS AFTERNOON AS THE NEXT COLD FRONT APPROACHES FROM THE W...WEAKENING THE PRESSURE GRADIENT. BOTH THE GFS AND ECMWF SHOW THAT FRONT MOVING INTO THE NW WATERS MON EVENING...REACHING FROM 31N77W TO 27N81W BY TUE MORNING... AND FROM 31N65W TO NORTHERN CUBA NEAR 80W WED MORNING. THE FRONT INTERACTS WITH THE AFOREMENTIONED AMPLIFYING TROUGHING OVER THE NE CARIBBEAN...LIMITING ITS SOUTHERN PROGRESS BY WED. CONFIDENCE IN THE GFS FORECAST WANES A BIT WED THROUGH FRI AS THE DETAILS BECOME MORE UNCERTAIN WITH THE INTERACTION OF THE FRONT AND TROUGH. IN ADDITION...THE GFS CARRIES A SLOWER AND STRONGER SYSTEM THROUGH THE N ATLC THAT IMPACTS THE SWELL OVER THE FORECAST AREA LATER IN THE WEEK THAN ALL OF THE OTHER GLOBAL GUIDANCE. THE ECMWF AND EC WAVE WERE BROUGHT INTO THE FORECAST BLEND TO ACCOUNT FOR THE UNCERTAINTY. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...GALE WARNING EARLY TODAY INTO TODAY. GMZ019...NONE. GMZ021...NONE. GMZ023...GALE WARNING EARLY TODAY INTO TUE. GMZ025...GALE WARNING TONIGHT INTO TUE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...GALE WARNING EARLY TODAY INTO TODAY AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.