000 AGXX40 KNHC 291945 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST SAT DEC 29 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... COLD FRONT CONTINUES TO MAKE SE PROGRESS ACROSS ERN GULF THIS AFTERNOON WHILE MOVING MORE SOUTHWARD ACROSS THE W GULF...NOW EXTENDING FROM NEAR THE CENTRAL FLORIDA/ORLANDO AREA SW TO NEAR 20.5N92W THEN DIVING MORE SSW INTO THE CHIVELAS PASS...WHERE A TEHUANTEPEC GALE EVENT HAS COMMENCED. A PRE FRONTAL TROUGH HAS BEEN EVIDENT SINCE LAST NIGHT JUST AHEAD OF THE BOUNDARY ACROSS THE SE PART BUT THESE TWO FEATURES HAVE NEARLY MERGED ACROSS THE EXTREME SE GULF...WHILE PRE FRONTAL TROUGHING REMAINS ACROSS THE YUCATAN. NLY FLOW BEHIND THE FRONT HAS BUILT SEAS 10-12 FT ACROSS W CENTRAL PORTIONS OF THE BASIN...BETWEEN 90W AND 95W... BASED ON MORNING BUOY OBS. THIS ABOUT 2-3 FT ABOVE WW3 GUIDANCE AND 1-2 FT ABOVE THE ECWAVE MODEL ACROSS THIS AREA. WINDS OF 20-25 KT ARE EXPECTED BEHIND THE FRONT THROUGH SUN MORNING...EXCEPT 25-30 KT S OF 23N...BEFORE GRADIENT WEAKENS W TO E. MAX SWH 13-14 FT EXPECTED LATE THIS AFTERNOON AND EVENING ALONG 94.5W-95W AS DYNAMIC NLY FETCH SHIFTS S INTO W HALF OF BAY OF CAMPECHE TONIGHT. OTHERWISE...BROAD FIELD OF 8-10 FT SEAS EXPECTED TO SHIFT E AND SE ACROSS E CENTRAL AND SE WATERS THROUGH TONIGHT AS FRONT MOVES THROUGH YUCATAN CHANNEL AND STRAITS OF FLORIDA...AND REACHES CENTRAL BAHAMAS TO ERN YUCATAN MID MORNING SUN. OROGRAPHIC DAMMING ALONG THE LOWER MEXICAN COAST MAY YIELD WINDS AT OR JUST BELOW GALE FORCE THIS EVENING BUT IS NOT SUGGESTED BY MODELS AND HAVE NOT ISSUED GALE WARNING FOR THIS ATTM. WINDS TO VEER QUICKLY N TO NE EARLY SUN THEN NE TO E SUN AFTERNOON AS HIGH BEHIND FRONT SLIDES EWD ACROSS MS VALLEY. WINDS THEN EXPECTED TO BECOME ELY SUN EVENING...WITH RETURN FLOW QUICKLY SETTING UP ACROSS TEXAS WATERS SUN NIGHT. FRESH FLOW THROUGH THE STRAITS AND OFF NW COAST OF YUCATAN WILL KEEP WINDS AOA 20 KT AND SEAS 6-8 FT THERE THROUGH MON MORNING BEFORE ABATING. YET ANOTHER COLD FRONT EXPECTED TO MOVE INTO THE WESTERN GULF OF MEXICO BY LATE MON. THIS FRONT IS PROGGED BY THE MODELS TO REACH FROM NEAR THE FLORIDA PANHANDLE TO THE WESTERN BAY OF CAMPECHE AREA TUE...THEN POSSIBLY SLOW DOWN AS THE UPPER FLOW PATTERN BECOMES SWLY AS A LARGE UPPER RIDGE BUILDS ACROSS THE REGION. MODELS THEN TEND TO DEVELOP WEAK LOW PRES ALONG THE FRONTAL BOUNDARY ON WED...WITH THE GFS MEAN ENSEMBLE VERY CLOSE IN AGREEMENT WITH THE ECMWF MEAN ENSEMBLE...BOTH VERY SIMILAR TO THEIR DETERMINISTIC GUIDANCE FOR THAT TIME. THIS LEADS TO BETTER THAN AVERAGE CONFIDENCE IN THIS FORECAST FOR DAY 5. SW N ATLC S OF 31N W OF 65W... WEAKENING 1023 MB HIGH CONTINUES TO BE NUDGED E-NE ACROSS THE CENTRAL ATLC TODAY AS E COAST DEEP LAYERED TROUGH SHIFTS EWD...AND ASSOCIATED FRONT HAS MOVED OFF SE COAST AND OFF NW FLORIDA. SWLY FLOW AHEAD OF FRONT WAS 25-30 KT BASED ON OBSERVATIONS THIS MORNING AND EARLY AFTERNOON...WITH SEAS BUILDING 8-10 FT ALONG AND N OF THE LOCAL WATERS. A NARROW ZONE OF GALE FORCE WINDS WAS QUITE POSSIBLE ALONG AND JUST AHEAD OF THE FRONT. HOWEVER...MORNING SCATTEROMETER PASSES MISSED THIS AREA. FLATTENING UPPER RIDGING ACROSS THE CARIBBEAN AND SW N ATLC WILL ALLOW FOR VERY PROGRESSIVE UPPER FLOW ACROSS W ATLC NEXT 48 HOURS...WITH COLD FRONT TO RACE E AND SE...REACHING BERMUDA TO CENTRAL BAHAMAS TO W CUBA SUN MORNING THEN 31N52W TO SE BAHAMAS TO E YUCATAN ALONG 20N MON MORNING THEN BECOMING NEARLY STATIONARY AND WEAKENING ALONG 20N BY TUE MORNING. MODELS SHOWING DEEP LAYERED LOW ACROSS NW ATLC BOMBING OUT WITH STORM CONDITIONS DEVELOPING TONIGHT WILL N OF THE AREA...AND GALE WINDS AHEAD OF THE FRONT JUST N OF THE AREA...POSSIBLY TO 30N TONIGHT...AND THEN ON BOTH SIDES OF FRONT JUST TO OUR N BORDER SUN NIGHT...BETWEEN 55W AND 65W. HAVE NOT INCLUDED GALES IN THE LOCAL HIGH SEAS FORECASTS AS OF YET. HOWEVER...THIS WILL NEED TO BE EVALUATED CLOSELY NEXT 24 HOURS. GFS ENSEMBLE PROBABILISTIC FORECASTS KEEP GALES N OF 31N...BUT COULD SEEN GALES REACHING TO 30N BEHIND FRONT SUN NIGHT AND MON. LARGE NW SWELL GENERATED BEHIND THIS FRONT WELL TO THE N OF THE FORECAST WATERS WILL PROPAGATE SE AND PRODUCE A LARGE SWELL EVENT FOR THE REGIONAL ATLC WATERS AS WELL AS CARIBBEAN ISLANDS. LEADING EDGE OF SWELL TO REACH N COASTS OF LESSER ANTILLES MON EVENING AND INTO N LEEWARDS BY TUE MORNING...WITH 8-10 FT SWELL AT 15-16 SECONDS. THIS ENERGY WILL INDUCE VERY LARGE SURGE AND COASTAL FLOODING ALONG EXPOSED COASTLINES OF THE ISLAND CHAIN. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... WEAK HIGH PRES SLIDING E-NE ACROSS THE W CENTRAL ATLC IS MAINTAINING FRESH TO STRONG E TO E-NE TRADES ACROSS THE CENTRAL CARIBBEAN...WHERE 20-25 KT TRADES PREVAIL ACROSS A BROAD SWATCH BETWEEN 67W-80W...WITH WINDS OF 25-30 KT OFF THE COAST OF COLOMBIA AS OBSERVED BY A RECENT 1504 UTC ASCAT PASS. BUOY 42058 HAS SURPRISINGLY PEAKED AT 11 FT AT 18Z IN RESPONSE TO VERY LONG FETCH AND LIKELY PULSING TO 25 KT AS HIGH AS 15N. THIS IS ABOUT 2 FT ABOVE WW3 GUIDANCE. WIND AND SEAS ACROSS THIS PORTION OF THE CARIBBEAN WILL ONLY SUBSIDE A TAD THROUGH EARLY NEXT WEEK AS COLD FRONT SWEEPS ACROSS SW N ATLC. THIS COLD FRONT IS FORECAST BY THE GFS/UKMET/ECMWF TO MOVE ACROSS YUCATAN CHANNEL LATE SUN AFTERNOON AND THEN BECOME NEARLY STATIONARY AS A SHEAR LINE ALONG 20N MON NIGHT-TUE...WITH NE WINDS 20 TO LOCALLY 25 KT ON BOTH SIDES OF FRONT SUN NIGHT THROUGH MON EVENING...WHILE SEAS BUILD TO 6-9 FT ACROSS NW PORTIONS. BY TUE THE BOUNDARY BEGINS TO DISSIPATE WITH ASSOCIATED WIND/SEA CONDITIONS DIMINISHING INTO WED. N-NW SWELL WILL MENTIONED ABOVE WILL BLEED THROUGH THE ATLC PASSAGES AND HIT NW COASTS OF EXPOSED LEEWARD ISLANDS...AS WELL AS VENEZUELA. 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 STRIPLING