000 AGXX40 KNHC 020707 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 210 AM EST SUN DEC 02 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... STRONG HIGH PRES JUST OFFSHORE OF THE CAROLINAS WILL DRIVE THE WINDS OVER THE GULF THROUGH TUE. A COLD FRONT WILL WEAKEN THIS HIGH PRES AND PUSH IT EASTWARD TUE INTO WED...WITH THE WEAKENED FRONT EXPECTED TO MOVE INTO THE NW GULF BY EARLY WED WITH LITTLE FANFARE ASIDE FROM SHOWERS AND THUNDERSTORMS. THE FRONT WILL DISSIPATE OVER THE NORTHERN GULF THU. MODERATE ANTICYCLONIC FLOW WILL DOMINATE MUCH OF THE REGION WITH THE EXCEPTION OF THE SE GULF THROUGH TUE. WITH THE 0334 UTC ASCAT AND 2254 UTC WINDSAT PASSES SHOWING FRESH TO STRONG E WINDS IN THE GULF S OF 25N E OF 90W INCLUDING THE STRAITS OF FLORIDA...WILL HEDGE TOWARD THE STRONGER 00Z GFS INITIALLY AS COMPARED TO THE WEAKER 00Z ECMWF AND UKMET. WITH THE DRIVING HIGH PRES EXPECTED TO MOVE S AND INCREASE THE PRES GRADIENT HERE UNTIL TUE...WILL KEEP WINDS FRESH TO STRONG WHICH IS SLIGHTLY ABOVE THE GFS GUIDANCE. THE WW3 TYPICALLY DOES NOT CAPTURE PEAK AREA OF SEAS THROUGH THE STRAITS AND ACROSS YUCATAN CHANNEL WHEN WINDS ARE AGAINST THE CURRENT. GRIDS WILL GO ABOVE GUIDANCE IN THE UPDATED FORECAST...WITH SEAS LIKELY TO LINGER AROUND 6-8 FT TILL TUE...AND LIKELY EVEN HIGHER AGAINST CURRENT. SHIP C6VG7 REPORTED 10 FT SEAS IN THE STRAITS OF FLORIDA AT 0000 AND 0200 UTC. THIS IS 5 FT HIGHER THAN THE 00Z WW3 AND 4 FT HIGHER THAN THE 00Z EC WAVE. OTHERWISE...THE 00Z GFS AND ECMWF ARE IN GOOD AGREEMENT ON THE PATTERN HERE...INCLUDING THE FRONTAL TIMING ON WED. A BLEND OF THEIR SOLUTIONS WILL BE USED TO UPDATE THE GRIDS BEYOND TUE. CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N W OF 55W... STRONG HIGH PRES JUST OFF THE CAROLINA COAST IS DRIVING THE EASTERLY FLOW THROUGH THIS REGION. A SHEAR LINE MAINLY N OF THE AREA HAS DIPPED SOUTHWARD...ALLOWING FRESH WINDS TO PENETRATE THE AREA IN THE LEE OF CUBA AS WELL AS THE WINDWARD PASSAGE. OTHERWISE...MODERATE TO LIGHT NE TRADES WILL PREVAIL ACROSS THE REGION THROUGH TUE. THE 0150 UTC ASCAT PASS CAPTURED 20 KT NE WINDS IN THE WINDWARD PASSAGE. THE 00Z GFS AND ECMWF ARE ABOUT 5 KT WEAKER HERE. THE GLOBAL MODELS SEEM TO HAVE A HARD TIME RESOLVING THE FUNNELING THROUGH THE WINDWARD PASSAGE. THEY ARE FREQUENTLY TOO LOW WITH THE WIND SPEED HERE UNDER A BROADLY FRESH TO STRONG NE FLOW REGIME. ONCE AGAIN...BUMPED THE WINDS UP 5 KT COMPARED TO THE MODELS SUN THROUGH TUE AND ADJUSTED SEAS ACCORDINGLY. AFTER TUE...THE DRIVING HIGH PRES TO THE N SHOULD SHIFT EASTWARD AND PUSH THE SHEAR LINE TO THE E AS WELL. THICKNESS PACKING WILL INCREASE W OF THE SHEAR LINE AND IT IS EXPECTED TO TRANSITION BACK TO A COLD FRONT BY WED. CONFIDENCE IS LOW WITH THE DETAILS OF THE FORECAST FOR THIS BOUNDARY...WITH THE 00Z GFS MORE EXCITED THAN THE ECMWF ABOUT DEVELOPING SURFACE WAVES ALONG THE BOUNDARY NE OF THE AREA STARTING MON NIGHT WHICH INFLUENCE THE POSITION OF THE BOUNDARY. A BLEND OF THE GENERALLY RELIABLE GFS AND ECMWF FORECASTS WAS USED FROM MON NIGHT ONWARD. SW N ATLC N OF 19N W OF 55W... A SHEAR LINE LIES FROM 25N55W THROUGH 23N70W TO 21N76W AS OF 00Z...WITH MAINLY FRESH TO STRONG E-NE WINDS TO THE N AND MODERATE E-NE WINDS TO THE S OF THE SHEAR LINE. BUOYS 41047...41043...AND 41046 ALL REPORTED 10 FT SEAS AT 0000 UTC E OF BAHAMAS AND N OF THE SHEAR LINE. THE 00Z WW3 IS RUNNING ABOUT A FOOT LOW AND THE EC WAVE IS ABOUT 2 FT LOW. THE SHEAR LINE IS EXPECTED TO MOVE S OVER THE NEXT FEW DAYS AS THE HIGH PRES JUST OFF THE NORTH CAROLINA COAST AT PRESENT DIPS SOUTHWARD TODAY THROUGH TUE BEFORE WEAKENING. E OF THE FORECAST AREA...A GALE WARNING IS IN EFFECT N OF THE 1008 MB LOW PRES SYSTEM NEAR 28N42W. BOTH THE 00Z GFS OR ECMWF FAIL TO SHOW GALE FORCE WINDS WITH THE SYSTEM AND DO NOT FORECAST THEM IN THE HSFAT2 AREA. HOWEVER...THE 0012 UTC ASCAT PASS SHOWED WINDS TO JUST BELOW GALE FORCE ON THE E SIDE OF THE LOW...AND THAT PASS FAILED TO CAPTURE MUCH OF THE CIRCULATION AROUND THE CENTER. THIS SYSTEM IS BEING DRAWN NORTHWARD TOWARD THE LEADING EDGE OF THE AFOREMENTIONED SHEAR LINE. IT HAS THE POTENTIAL TO BRIEFLY BECOME A TROPICAL CYCLONE BEFORE MOVING N OF THE FORECAST AREA LATER TODAY...ALTHOUGH THE ODDS OF THIS HAPPENING ARE RAPIDLY DWINDLING. THE 00Z GFS HAS TRENDED TOWARD A WEAKER LOW CENTER AS IT MOVES NORTHWARD COMPARED TO THE REMAINDER OF THE 00Z GUIDANCE. THE STRONGER SOLUTION HAS PANNED OUT MORE FREQUENTLY WITH THIS SYSTEM...SO WILL BLEND THE PREVIOUS FORECAST WITH THE 00Z ECMWF HERE. THE SYSTEM IS EXPECTED TO BECOME FRONTAL SOMETIME IN THE NEXT 36-60 HOURS. CLOSE TO THE FORECAST AREA...THE 00Z GEFS HAS COMPLETELY BACKED OFF ON ANY CHANCE FOR GALES DEVELOPING THROUGH THU WITH THE NEXT POSSIBLE LOW PRES SYSTEMS EXPECTED MANIFEST THEMSELVES AS SURFACE WAVES ALONG THE SHEAR LINE OVER SE WATERS MON AND LIFT NE AWAY FROM THE AREA THROUGH THU. THE 00Z ECMWF AND GFS AGREE ON THE DEVELOPMENT OF A POSITIVELY-TILTED DEEP-LAYERED TROUGH SETTING UP FROM NE HSFAT2 WATERS TO HISPANIOLA DURING THIS TIME AND CARRY ANY SURFACE WAVES QUICKLY NORTHEASTWARD ALONG THE BOUNDARY AND E OF THE FORECAST AREA. CONFIDENCE IS LOW IN THE DETAILS WITH THESE SURFACE WAVES. A BLEND OF THE 00Z GFS AND ECMWF WILL BE USED TO ACCOUNT FOR THE UNCERTAINTY IN THE FORECAST HERE. 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