000 AGXX40 KNHC 091825 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 125 PM EST SUN DEC 9 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... CONDITIONS ARE RELATIVELY TRANQUIL IN THE GULF AT THE MOMENT BEFORE THE INTRUSION OF THE COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST MON MORNING. THE GLOBAL MODELS HAVE GENERALLY BACKED OFF ON THE STRENGTH OF THIS FRONT...ALLOWING THE MID LEVEL ENERGY ASSOCIATED WITH THE DEEP-LAYER TROUGH TO PASS WELL TO THE N OF THE GULF ON MON AND TUE. THE 06Z GEFS MEMBERS ONLY SHOW A CHANCE OF GALE FORCE WINDS ALONG THE MEXICAN COAST AROUND 0000 UTC TUE...BUT GET AS HIGH AS A 90 PERCENT CHANCE. EVEN THE 0600 UTC GEFS MEAN SHOWS AN AREA OF 35 KT WINDS AT THIS TIME. HOWEVER...THE 0000 UTC ECMWF IS CONSIDERABLY LESS ENTHUSIASTIC...WITH ITS ENSEMBLE MEAN NEVER CARRYING WINDS ABOVE 25 KT BEHIND THE FRONT AND THE DETERMINISTIC RUN ALSO CAPPING WINDS AT 25 KT. THE UKMET...WHICH IS CONSIDERED TO GENERALLY PERFORM WELL IN SUCH SITUATIONS...CARRIES 30 KT WINDS BEHIND THE BOUNDARY MON INTO MON NIGHT. THE UKMET APPEARS TO BE A REASONABLE COMPROMISE BETWEEN THE AVAILABLE SOLUTIONS AND ABIDES BY CONTINUITY WHICH DOES NOT INCLUDE A GALE WARNING HERE. THE MODELS THEN AGREE ON CARRYING A MORE AMPLIFIED MID-LEVEL TROUGH THROUGH THE NORTHERN GULF WED THAT WILL REINFORCE THE COLD FRONT AND ENHANCE WINDS BEHIND THE FRONT TUE NIGHT AND WED. THE 1200 UTC GFS SOLUTION LOOKS REASONABLE HERE. THE GFS AND ITS WW3 ARE IN DECENT AGREEMENT WITH THE UKMET AND ITS WAVE MODEL TUE NIGHT INTO WED. THE 1200 UTC GFS WAS RELIED ON FOR THE FORECAST TUE NIGHT AND BEYOND. CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N W OF 55W... THE 1200 UTC GFS HAS CAUGHT ON TO THE FRESH TO STRONG NE WIND FOUND JUST E OF THE AREA FROM 13N TO 20N ACCORDING TO THE 1324 UTC ASCAT PASS. THE PREVIOUS RUN WAS NOT AS STRONG. THE 1200 UTC ALSO APPEARS WELL INITIALIZED IN THE CENTRAL CARIBBEAN. THE SUBTROPICAL HIGH DRIVING THE WINDS IN THE REGION WILL SHIFT EASTWARD BEGINNING TONIGHT AS THE COLD FRONT EXPECTED TO PASS THROUGH THE GULF OF MEXICO ADVANCES EASTWARD. THE STRONGEST WINDS WILL GRADUALLY SHIFT EASTWARD WITH THE STRONGEST PRESSURE GRADIENT. THE COLD FRONT IS EXPECTED TO CLIP THE YUCATAN CHANNEL LATE THU NIGHT. THE 0000 UTC GFS SEEMS REASONABLE HERE. SW N ATLC FROM 19N TO 31N W OF 55W... THE 1200 UTC GFS IS REASONABLY WELL INITIALIZED WITH THE TROUGHING ALONG THE NE FLORIDA COAST...SHOWING A MORE DISTINCT TROUGH AND WIND SHIFT THAN THE 0000 UTC ECMWF SOLUTION. WINDS ARE LIGHT TO MODERATE TODAY THROUGH THE REGION WITH THE EXCEPTION OF FRESH NE TRADES IN THE FAR SE CORNER. THE GLOBAL MODELS DO A GOOD JOB CAPTURING THE BROADER WIND FIELD. THE WW3 IS A FOOT OR TWO LOW WINDS THE SEAS JUST E OF THE BAHAMA BANK ACCORDING TO SHIPS KIRH AND 9HA3047 AS WELL AS BUOY 41046. SEAS WERE BUMPED UP INITIALLY AND INTO THE BEGINNING OF THE FORECAST PERIOD AS THE RESIDUAL NE SWELL IN PLACE SUBSIDES. THE MODELS DIVERGE WITH THE STRENGTH AND TIMING OF THE COLD FRONT EXPECTED TO PASS THROUGH THE GULF AND APPROACH NW WATERS ON TUE. THE 1200 UTC GFS CARRIES A WAVE ALONG THE BOUNDARY OVER NW WATERS TUE MORNING AND HAS WINDS TO 25 KT IN THE SOUTHERLY FLOW. THE 0000 UTC ECMWF AND 1200 UTC UKMET ARE NOT AS AMPLIFIED WITH THIS WAVE. BELIEVE THAT GFS GRID SCALE FEEDBACK MAY BE INTENSIFYING THE MID-LEVEL ENERGY ON THE LEADING EDGE OF THE MEAN TROUGH MORE THAN EXPECTED...SO THE FORECAST SIDES WITH THE WEAKER ECMWF AND UKMET HERE. THE GFS AND ECMWF AGREE ON TEMPORARILY STALLING THE FRONT OVER NW WATERS UNTIL A NEW MID-LEVEL TROUGH SWINGS THROUGH AND INVIGORATES THE BOUNDARY WED...WITH BOTH MODELS SHOWING 25 KT SOUTHERLY WINDS AHEAD OF THE BOUNDARY AT 1800 UTC WED. THE GFS BECOMES SLOWER THAN THE REMAINING GLOBAL GUIDANCE AFTER THIS TIME...SO THE ECMWF WAS BLENDED INTO THE FORECAST TO HEDGE IT TOWARD THE MODEL CONSENSUS. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER