000 AGXX40 KNHC 250745 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 AM EST WED DEC 25 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 AND ECMWF. PREVIOUS FORECAST AND NWPS/MWW3 BLEND USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE ASCAT PASSES FROM 0220Z AND 0306Z SHOW WINDS ARE 5 KT STRONGER BEHIND THE FRONT ACROSS THE SW GULF AND EASTERN GULF THAN THE PREVIOUS OFFICIAL GRIDS. THE OFFICIAL GRIDS ALSO APPEAR TO BE AROUND A FOOT TOO LOW COMPARED TO BUOY AND ALTIMETER OBSERVATIONS IN THE GULF S OF 27N. CHANGES WILL BE MADE TO THE NOW-CAST TO ACCOUNT FOR THESE DISCREPANCIES. THE AFOREMENTIONED ASCAT PASSES SHOW THE DEVELOPMENT OF A SURFACE TROUGH OFFSHORE OF VERACRUZ WHICH HAS BEEN ADDED TO THE SURFACE ANALYSIS. THE COLD FRONT LIES FROM THE FLORIDA KEYS TO THE YUCATAN CHANNEL AND WILL SOON PUSH SE OF THE GULF. WINDS WILL DIMINISH TO MODERATE TO FRESH LEVELS FROM THE NW GULF TO THE SE TODAY AS THE FRONT MOVES AWAY AND HIGH PRES BUILDS IN FROM THE NW. THE MID-LEVEL REMNANTS OF THE FRONT ARE FORECAST TO RETROGRADE BACK INTO THE SOUTHERN PORTION OF THE BASIN TONIGHT INTO THU... TIGHTENING THE PRESSURE GRADIENT. THE GFS CONTINUES TO SUFFER FROM GRID-SCALE FEEDBACK IMPACTING THE FORECAST WITH THE FRONTAL REMNANTS. IT STAMPS OUT ABOUT 2.5 INCHES OF PRECIPITATION IN 6 HOURS ON FRI MORNING AND BRIEFLY DEVELOPS A SURFACE LOW NEAR 25N87W AS A RESULT. WHILE THE ECMWF...UKMET...AND NAVGEM AGREE ON AN AMPLIFIED INVERTED TROUGH NEAR THIS LONGITUDE FRI MORNING...NONE OF THESE MODELS ARE AS BULLISH AS THE GFS. THEREFORE...A BLEND OF THE GFS AND TAMER ECMWF WAS USED TO ACCOUNT FOR THE SEEMINGLY STRONG SOLUTION OF THE GFS. SIMILARLY...THE GFS DEVELOPS GALE FORCE WINDS W OF THE AFOREMENTIONED TROUGH IN THE SW GULF LATE THU AND THU NIGHT. WHILE THERE IS REASONABLE AGREEMENT ON 30 KT WINDS HERE...NONE OF THE OTHER MODELS IS AS STRONG AS THE GFS. GRID-SCALE FEEDBACK MAY ALSO BE CAUSING THE TROUGH HERE TO BE STRONGER IN THE GFS THAN THE OTHER MODELS. AGAIN...A BLEND OF THE GFS AND TAMER ECMWF WAS USED TO ACCOUNT FOR THE SEEMINGLY STRONG SOLUTION OF THE GFS. HIGH PRES TO THE N WEAKENS OVER THE WEEKEND...DIMINISHING THE WIND OVER MUCH OF THE GULF. THE GFS AND ECMWF BOTH CARRY A BROAD AREA OF LOW PRES NORTHEASTWARD FROM THE SW TO NE GULF OVER THE WEEKEND. THEIR DETAILS ARE SIGNIFICANTLY DIFFERENT. THE ECMWF SHOWS A MORE CLOSED OFF CIRCULATION ON A MORE WESTERLY TRACK THAN THE GFS. CONFIDENCE IN ANY ONE MODEL SOLUTION CONTINUES TO BE QUESTIONABLE. A BLEND OF THE GENERALLY RELIABLE GFS AND ECMWF SHOULD ACCOUNT FOR THE UNCERTAINTY FOR NOW. ...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 0218Z AND 0304Z ASCAT PASSES SHOW STRONGER WINDS IN THE LEE OF CUBA THAN ANY OF THE FORECAST MODELS OR THE PREVIOUS OFFICIAL GRIDS. ADJUSTMENTS WILL BE MADE TO THE NOW-CAST ACCORDINGLY. THE COLD FRONT APPROACHING FROM THE GULF OF MEXICO IS BEGINNING TO WASH OUT AS IT MOVES INTO THE YUCATAN CHANNEL. THE TRADE WINDS HAVE GENERALLY DIMINISHED ACROSS THE BASIN WITH THE PRESSURE GRADIENT SIGNIFICANTLY WEAKENED DUE TO THIS COLD FRONT AND AN AMPLIFYING SURFACE TROUGH NEAR 70W WHICH IS INTERACTING WITH A MID TO UPPER LEVEL LOW. SEAS HAVE SUBSIDED TO LESS THAN 8 FT OVER THE ENTIRE CARIBBEAN. THE COLD FRONT WILL DISSIPATE ALONG 20N TODAY BEFORE ITS MID-LEVEL REMNANTS GRADUALLY LIFT BACK TO THE NW AS THE TROUGH APPROACHES FROM THE E. THAT TROUGH WILL CONTINUE TO PRODUCE NUMEROUS SHOWERS AND SCATTERED TSTMS ACROSS THE EASTERN CARIBBEAN TODAY...SPREADING WESTWARD BY THU. OTHERWISE MAINLY MODERATE EASTERLY WINDS AND 3-6 FT SEAS WILL PREVAIL TODAY THROUGH EARLY FRI. CENTRAL ATLANTIC RIDGING WILL MANAGE TO BUILD BACK IN JUST N OF THE AREA FRI THROUGH SUN...ALLOWING FOR AN INCREASE IN TRADE IN THE CENTRAL CARIBBEAN...ESPECIALLY NEAR THE COAST OF COLOMBIA WHERE SEAS WILL BE BACK UP TO 8 FT BY LATE FRI THROUGH SAT...THEN BUILDING TO 10-11 FT BY SUN. THE GFS FORECAST SOLUTION CONTINUES TO LOOK REASONABLE HERE. IN THE TROPICAL N ATLC...THE SURFACE TROUGHING MENTIONED ABOVE IS ALSO PRODUCING NUMEROUS SHOWERS AND SCATTERED TSTMS OVER THE OFFSHORE WATERS. MODERATE TO FRESH E-SE WINDS AND 7-9 FT SEAS COVER THE TROPICAL N ATLC IN THE WAKE OF THE TROUGHING WITH THESE CONDITIONS PERSISTING INTO THE UPCOMING WEEKEND. ...SW N ATLANTIC W OF 65W INCLUDING THE BAHAMAS... PREVIOUS/OFFICIAL FORECAST BLENDED WITH LATEST GFS AND ECMWF. NWPS/MWW3/EC WAVE BLEND USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. A COLD FRONT EXTENDS FROM 31N78W TO THE STRAITS OF FLORIDA WITH FRESH TO STRONG WINDS AND 6-8 FT SEAS BEHIND IT. A VERY NARROW STRIP OF SHOWERS IS ACCOMPANYING THE FRONT. MODERATE TO FRESH SOUTHERLY RETURN FLOW IS AHEAD OF THE FRONT ACROSS THE NORTHERN WATERS...WITH INCREASING NE WINDS AND BUILDING SEAS ACROSS THE SOUTHERN WATERS AS THE ABOVE MENTIONED SURFACE TROUGHING IS NOW MOVING ACROSS PUERTO RICO WITH PLENTIFUL ASSOCIATED CONVECTION SPREADING INTO THE SE WATERS. BOTH THE GFS AND ECMWF SHOW THAT FRONT WILL STRETCH FROM 31N67W TO 27N74W TO 23N81W WED MORNING BEFORE INTERACTING WITH THE TROUGHING WHICH WILL LIMIT THE FRONTS FORWARD PROGRESS. CONFIDENCE IN THE GFS FORECAST CONTINUES TO WANE A BIT WED THROUGH SUN AS THE DETAILS BECOME MORE UNCERTAIN WITH THE INTERACTION OF THE FRONT AND TROUGH. IN ADDITION...THE GFS CONTINUES TO CARRY A SLOWER AND WEAKER 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. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.