000 AGXX40 KNHC 110622 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 122 AM EST THU DEC 11 2014 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: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST THROUGH SUN THEN ECMWF ADDED TO THE BLEND. LATEST TAFB- NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE THROUGH SUN THEN MEDIUM CONFIDENCE. TROUGHING OVER THE CENTRAL N ATLC HAS WEAKENED THE SUBTROPICAL RIDGE AND WEAKENED THE PRESSURE GRADIENT OVER THE GULF OF MEXICO. A RIDGE BISECTS THE GULF OF MEXICO ALONG 90W...WITH A LIGHT TO GENTLE BREEZE DOMINATING THE AREA. THE HIGH PRES CENTERED OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO DOMINATE THE WINDS OVER THE GULF TONIGHT THROUGH SAT...WITH SE RETURN FLOW OVER THE WESTERN GULF. WINDS AND SEAS IN THE GULF OF MEXICO ARE EXPECTED TO REMAIN BELOW THE ADVISORY CRITERIA OF 20-25 KT AND 8 FT...RESPECTIVELY...THROUGH SUN. THE RIDGE WILL SHIFT INTO THE EASTERN GULF SUN AS TROUGHING BUILDS OVER TEXAS...INCREASING THE PRES GRADIENT OVER THE W GULF. WHILE THE GFS KEEPS THE RETURN FLOW BELOW 25 KT...THE UKMET AND ECMWF DO NOT. THE UKMET IS MORE AGGRESSIVE THAN THE ECMWF. THE ECMWF WAS ADDED TO THE BLEND TO ACCOMMODATE THE MODEL CONSENSUS WHICH IS STRONGER THAN THE GFS...SHOWING A DEEPER AND SLOWER MOVING SURFACE LOW PASSING E THROUGH OKLAHOMA SUN NIGHT/MON MORNING THAN THE GFS. SEAS WERE BUMPED UP ON MON TO MATCH THE STRONGER WINDS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST THROUGH SAT THEN ECMWF ADDED TO THE BLEND. LATEST TAFB- NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. WHILE THE PRES GRADIENT WILL REMAIN WEAK AS TROUGHING OVER THE CENTRAL AND SW N ATLC CONTINUES TO BE REINFORCED TODAY THROUGH FRI...WINDS ARE STILL EXPECTED TO REACH THE 20-25 KT THRESHOLD ALONG THE COAST OF COLOMBIA...PEAKING IN THE EARLY MORNING HOURS...TODAY THROUGH SAT. THE 0256 UTC ASCAT PASS SHOWS WINDS ARE ALREADY A FRESH TO STRONG BREEZE HERE AS WELL AS IN THE LEE OF EASTERN CUBA. NONE OF THE MODELS ARE STRONG ENOUGH IN EITHER LOCATION. THE GFS IS GENERALLY THE MODEL TO BEAT OFF COLOMBIA...SO THE FORECAST WAS ADJUST TOWARD ITS SOLUTION...BUT WAS BUMPED UP TO MATCH THE OBSERVATIONS AND IN THE SHORT TERM. THE NWPS-ADJUSTED WAVES WERE ALSO BUMPED UP A BIT TODAY THROUGH FRI. BY SUN...THE ECMWF AND UKMET AGREE ON DEVELOPING AN AREA OF LOW PRES IN THE SW CARIBBEAN WHILE THE GFS IS CONSIDERABLY WEAKER...FAVORING ENHANCED TROUGHING ALONG THE MONSOON TROUGH AT BEST. CONFIDENCE IS LOW IN ONE SOLUTION OVER ANOTHER HERE...SO A BLEND OF THE GFS AND ECMWF WAS USED FROM SUN ONWARD. IN THE TROPICAL N ATLC...LARGE N AND NE SWELL HAS BLANKETED THE AREA. THIS SWELL WILL SUBSIDE TO 8 FT OR LESS THROUGH SAT. A 2200 UTC ALTIKA PASS SHOWED SEAS AS HIGH AS 14 FT AND BUOY 41044 WAS AS HIGH AS 12 FT AT 0400 UTC. THE MWW3 IS APPROXIMATELY 4 FT TOO LOW WITH THE HIGHEST SEAS HERE. THE NWPS IS AN IMPROVEMENT...RUNNING ABOUT 2-3 FT HIGHEST THAN THE MWW3...BUT ADJUSTMENT STILL NEEDED TO BE MADE TO MATCH THE OBS AND WITH THE SHORT TERM FORECAST. ...SW N ATLANTIC S OF 31N W OF 55W INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST THROUGH SUN THEN ECMWF ADDED TO THE BLEND. LATEST TAFB- NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. OBSERVATIONS SHOW WINDS HAVE DIMINISHED BELOW A STRONG BREEZE OVER THE AREA. SEAS ARE BEGINNING THE SUBSIDE...WITH THE MWW3 APPEARING TOO FAST TO SUBSIDE THE HIGHEST SEAS JUST E OF THE SOUTHERN BAHAMAS COMPARED TO THE 0200 UTC JASON2 PASS. THE NWPS IS IN BETTER AGREEMENT WITH THE OBS AND WAS USED TO ADJUST THE FORECAST. SEAS WILL GRADUALLY SUBSIDE BELOW 8 FT W OF 70W FRI AND ELSEWHERE SAT. THE COLD FRONT CURRENTLY STRETCHED FROM 31N62W TO THE WINDWARD PASSAGE WILL STALL AND WEAKEN TODAY BEFORE DISSIPATING TONIGHT AS A NEW COLD FRONT MOVES INTO THE AREA. THIS NEW COLD FRONT IS EXPECTED TO LIE FROM NEAR BERMUDA TO 28N74W TO MAYPORT FLORIDA FRI NIGHT AND FROM 31N63W TO EASTERN CUBA SAT NIGHT BEFORE WEAKENING AND SLOWLY MOVING THROUGH SE WATERS SUN NIGHT THROUGH TUE. CONDITONS WILL BE MORE TRANQUIL FRI THROUGH THE WEEKEND AS RIDGING MOVES IN BEHIND THE FRONT. BY SUN NIGHT...THE MODELS DIVERGE SLIGHTLY WITH THE SPEED OF THE FRONT AND THE STRENGTH OF THE ANCHOR LOW N OF THE AREA...WITH THE GFS WEAKER AND FASTER THAN THE ECMWF AND UKMET. THE ECMWF WAS ADDED TO THE BLEND TO HELP ACCOUNT FOR THAT DIFFERENCE BETWEEN THE GFS AND THE MODEL CONSENSUS LATE IN THE PERIOD...BUT WINDS AND SEAS SHOULD BE BELOW ADVISORY CRITERIA REGARDLESS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.