000 AGXX40 KNHC 171837 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 145 PM EST THU JAN 17 2013 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... A COLD FRONT EXTENDING FROM TAMPA BAY TO THE YUCATAN CHANNEL WILL SWEEP THROUGH THE SE GULF WATERS THROUGH TONIGHT. IN THE SW GULF...THE COMBINATION OF A TIGHT PRES GRADIENT AND RELATIVELY STRONG COLD AIR ADVECTION BEHIND THE FRONT HAVE ALLOWED WINDS TO GALE FORCE NEAR THE MEXICAN COAST...WITH THE LAST WINDS TO GALE FORCE ARE DIMINISHING THIS MORNING. CIUDAD DEL CARMEN REPORTED 35 KT N WINDS AT 1200 UTC...BUT THE WINDS HAVE SINCE DIMINISHED TO 20 KT. THE UPPER SUPPORT FOR THE FRONT IS A VIGOROUS MID/UPPER LEVEL DISTURBANCE CURRENTLY MOVING THROUGH THE SE U.S. THAT HAS TURNED SLIGHTLY NEGATIVE TILT. THE 1506 UTC ASCAT PASS SHOWS NW WINDS TO NEAR GALE FORCE BEHIND THE FRONT TO 88W N OF 28N. SUSTAINED WINDS AT BUOY 42040 AND 42039 HAVE CONFIRMED THESE CONDITIONS AND HAVE SHOWN FREQUENT GUSTS TO GALE FORCE. NEITHER THE 1200 UTC GFS NOR THE 0000 UTC ECMWF FORECAST SUSTAINED GALE FORCE WINDS IN THE OFFSHORE ZONE HERE. A GALE WARNING HAS BEEN ISSUED UNTIL TONIGHT FOR FREQUENT GUSTS TO GALE FORCE IN THE NE GULF BEHIND THE FRONT N OF 28N. SEAS WERE 3-4 FT HIGHER HERE THAN THE MWW3 AND 2-3 FT HIGHER THAN THE ECMWF WAVE MODEL THIS MORNING AT 1200 UTC. THE SWELL IS ALSO SLOWER TO SUBSIDE IN THE SW GULF THAN THE MWW3 PREDICTED...WITH BUOY 42055 REPORTING 13 FT SEAS AT 1200 UTC THIS MORNING. THE MWW3 REPORTED 10 FT SEAS HERE WHILE THE ECMWF WAVE MODEL WAS ONLY A FOOT TOO LOW. SEAS WERE BUMPED UP COMPARED TO THE MWW3 TO ACCOUNT FOR ITS POOR INITIALIZATION. ELSEWHERE FOR TODAY...SEAS OF 8 TO 11 FT CAN BE EXPECTED ACROSS THE EASTERN GULF...WITH SEAS SUBSIDING TO 2 TO 4 FT OVER THE NW GULF. WINDS AND SEAS DIMINISH ACROSS THE ENTIRE GULF FRI THROUGH LATE SAT AS BROAD HIGH PRES BUILDS N OF THE AREA. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... FRESH TO STRONG TRADES WILL GRADUALLY DIMINISH OVER THE NEXT 24 HOURS IN THE CENTRAL CARIBBEAN AS THE DRIVING SUBTROPICAL RIDGE TO THE N IS FORCED EASTWARD. WINDS AND SEAS APPEAR TO BE REASONABLY WELL INITIALIZED BY THE 1200 UTC GFS AND MWW3. A COLD FRONT WILL REACH THE YUCATAN CHANNEL TONIGHT...THEN STALL FROM CENTRAL CUBA TO EASTERN HONDURAS FRI AND BECOME DIFFUSE SAT. FRESH TO STRONG NW TO N WINDS WILL FOLLOW THE FRONT ACROSS MUCH OF THE FAR NW CARIBBEAN WITH BUILDING SEAS UP TO 8 TO 10 FT TONIGHT AND FRI BEFORE GRADUALLY SUBSIDING TO LESS THAN 8 FT ON SAT. FRESH TO STRONG TRADES RETURN TO THE COAST OF COLOMBIA BY SAT AS HIGH PRES BUILDS TO THE N BEHIND THE COLD FRONT. IN THE TROPICAL N ATLC...CONDITIONS WILL REMAIN BELOW ADVISORY CRITERIA UNTIL MON WHEN BUILDING HIGH PRES TO THE N EXPANDS THE AREA OF FRESH TRADES AND RAISES SEAS TO 8 FT. SW N ATLC S OF 31N W OF 55W... BUOYS 41010 AND 41012 ARE UNDER A FRESH S-SW BREEZE AHEAD OF A COLD FRONT EXPECTED TO ENTER NW WATERS THIS EVENING. A SLIGHTLY NEGATIVELY TILTED MID/UPPER TROUGH ASSOCIATED WITH THIS COLD FRONT WILL SWING THROUGH THE SE UNITED STATES BEFORE ACCELERATING NORTHEASTWARD FRI. SURFACE LOW PRES WILL SHIFT INTO THE CAROLINAS TODAY...AND OFF THE NC COAST TONIGHT. WINDS OFF NE FLORIDA WILL INCREASE AS THE LOW PRES PASSES N OF THE AREA. THE 1200 UTC GEFS SHOWS THE PROBABILITY OF SUSTAINED GALE FORCE WINDS LIES JUST N OF 31N BEGINNING TONIGHT AT 0000 UTC...BUT THE 0600 UTC RUN WAS MORE ENTHUSIASTIC SHOWING A 20-30 PERCENT CHANCE WITHIN THE FORECAST AREA. THE SYSTEM IS SLIGHTLY STRONGER THAN INITIALIZED OVER THE GULF OF MEXICO...AND CONSIDERING WATER TEMPERATURES ARE STILL REASONABLY HERE....ESPECIALLY ALONG THE GULF STREAM...THINK THE GALE FORCE WINDS WILL BE ABLE TO MIX DOWN BEHIND THE FRONT. A SECONDARY SURGE OF COLD AIR IS EXPECTED TO CONTINUE THE GALE OVER NW WATERS INTO FRI MORNING...WITH THE 1200 UTC GEFS SHOWING UP TO A 30 PERCENT CHANCE OF SUSTAINED GALE FORCE WINDS BEFORE DIMINISHING LATE FRI. A GALE WARNING HAS BEEN ISSUED FOR N OF 29N W OF 78W FOR TONIGHT AND FRI. THE COLD FRONT WILL REACH FROM 31N72W TO CENTRAL CUBA BY EARLY FRI...AND STALL FROM 29N65W TO THE CENTRAL BAHAMAS OVER THE WEEKEND. WINDS AND SEAS DIMINISH SAT LEAVING LIGHT TO MODERATE NORTHERLY FLOW N OF THE FRONT INTO MON. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE WARNINGS... GULF OF MEXICO... .GALE WARNING N OF 28N TODAY FOR FREQUENT GUSTS TO GALE FORCE...GMZ015. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .GALE WARNING N OF 29N W OF 78W TONIGHT AND FRI...AMZ111. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER