000 AGXX40 KNHC 100705 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EST THU JAN 10 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... SURFACE AND PLATFORM OBSERVATIONS ALONG WITH THE 0226 UTC ASCAT PASS SHOW THE STRONGEST WINDS IN THE GULF ARE WELL AHEAD OF THE COLD FRONT IN THE EASTERN GULF. THE 0000 UTC GFS APPEARS TO BE SLIGHTLY BETTER INITIALIZED THAN THE 0000 UTC ECMWF WITH THE WIND FIELD. LATER TODAY...THE GFS CONTINUES TO CARRY A STRONGER VORT ON THE SE SIDE OF THE LOW INTO SE LOUISIANA COMPARED TO THE OTHER MODELS AND SHOWS HIGHER WINDS ALONG THE N CENTRAL GULF COAST COMPARED TO THE ECMWF AND UKMET AS A RESULT...POSSIBLY DUE TO GRID-SCALE FEEDBACK. HOWEVER...WITH THE STRONG LOW-LEVEL SOUTHERLY JET EXPECTED TO BE IN PLACE AHEAD OF THE FRONT OVERNIGHT THU NIGHT...DO NOT WISH TO BACK OFF TOO MUCH ON THE GFS FORECAST. THE NOGAPS SHOWS BETTER AGREEMENT WITH THE GFS. THE FRONTAL BOUNDARY DISSIPATES OVER THE GULF FRI AS THE IMPETUS DEEP-LAYER LOW LIFTS WELL N OF THE AREA AND DEEP-LAYER RIDGING BUILDS OVER THE CENTRAL AND EASTERN GULF. A BROAD UPPER TROUGH BEGINS TO WORK ITS WAY INTO THE WESTERN GULF BY SAT. THE GFS CARRIES THE ASSOCIATED COLD FRONT TO THE TEXAS COAST BY 1200 UTC SUN WHILE THE SLOWER ECMWF HAS IT THERE ABOUT 6 HOURS LATER. FOR NOW...A BLEND OF THE GFS AND ECMWF WILL BE USED TO ADJUST THE FORECAST FROM 0000 UTC SUN ONWARD...WITH THE GFS PREFERRED EARLIER IN THE PERIOD. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... THE 2258 UTC WINDSAT PASS SHOWED A LARGE AREA OF NEAR GALE FORCE WINDS OVER THE CENTRAL CARIBBEAN PRIMARILY S OF 15N ALONG 76W...WELL PAST THE DIURNAL MAXIMA OF WIND HERE. SHIPS PCIH AND C6JS ALSO REPORTED GALE FORCE WINDS JUST W OF THIS AREA AT 0600 UTC. THE 0000 UTC GFS IS THE BEST INITIALIZED MODEL HERE. A GALE WARNING IS IN EFFECT NEAR THE COAST OF COLOMBIA AND WILL CONTINUE UNTIL MIDDAY FRI WHEN THE RIDGING OVER THE SW N ATLC BEGINS TO WEAKEN. THE 0000 UTC GEFS SHOW NO CHANCE OF A GALE FROM FRI AFTERNOON ONWARD. ELSEWHERE...FRESH TO STRONG TRADES IN THE NW CARIBBEAN AND THE WINDWARD PASSAGE ARE EXPECTED TO DIMINISH FRI INTO THE WEEKEND AS THE RIDGE IN THE SW N ATLC WEAKENS. IN THE TROPICAL N ATLC...WINDS HAVE DIMINISHED TO S FRESH BREEZE COMPARED WITH THIS TIME LAST NIGHT AND SEAS WILL CONTINUE TO SUBSIDE THROUGH SAT AS A LOW PRES SYSTEM DIVES SOUTHEASTWARD INTO THE CENTRAL ATLC AND WEAKENS THE SUBTROPICAL RIDGE THERE. THE EC WAVE CONTINUES TO BE FASTER CARRYING THE SWELL FROM THE CENTRAL ATLC SYSTEM S INTO THE TROPICAL ATLC THAN THE GFS-BASED WW3. THE NCEP/FNMOC ENSEMBLE MEAN IS SLOWER WITH THE SOUTHERN EDGE OF THE SWELL LIKE THE GFS...BUT IS MORE IN LINE WITH THE ECMWF WITH THE WESTERN EDGE OF THE SWELL AS WELL AS WITH PROGRESSION OF THE SEAS OVER 12 FT. CONFIDENCE IS LOW IN THE DETAILS...SO A BLEND OF THE WW3 AND EC WAVE WAS USED TO UPDATE THE FORECAST HERE. SW N ATLC S OF 31N W OF 55W... THE 0144 UTC ASCAT PASS SHOWS FRESH TO STRONG TRADEWINDS S OF 24N N OF THE ANTILLES...WITH NEAR GALE FORCE WINDS IN THE ATLC APPROACHES TO THE WINDWARD PASSAGE. A SOLID AREA OF STRONG TO NEAR GALE FORCE TRADES IS EXPECTED BETWEEN THE TURKS AND CAICOS AND THE WINDWARD PASSAGE THROUGH TONIGHT WITH SEAS IN THE 8-10 FT RANGE FORECAST TO DIMINISH AS THE SW N ATLC RIDGING WEAKENS. THE 0000 UTC GFS IS THE STRONGEST AND BEST INITIALIZED MODEL HERE. THE AFOREMENTIONED SYSTEM IN THE CENTRAL ATLC BECOMES A PLAYER PRIMARILY OVER WATERS E OF 70W FRI INTO THE WEEKEND. AS MENTIONED IN THE SECTION ABOVE...THE WW3 IS SLOWER THAN THE NCEP/FNMOC ENSEMBLE AND THE EC WAVE TO SPREAD THE SWELL WESTWARD INTO THIS AREA. A BLEND OF THE GFS AND EC WAVE WAS USED A RESULT. BOTH THE 0000 UTC ECMWF AND GFS CONFINE WINDS TO 25 KT TO THE FAR NE CORNER OF THE AREA...WELL E OF THE OFFSHORE ZONES. GALE FORCE WINDS ARE EXPECTED IN THE HFSAT2 AREA WELL E OF 55W. A BLEND OF THE GFS AND ECMWF WIND FORECASTS WAS USED TO ACCOUNT FOR UNCERTAINTY...BUT THESE MODELS ARE ACTUALLY IN REASONABLE AGREEMENT. WEAKENING HIGH PRES MOVES S OF 31N NEAR 73W ON SAT. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .GALE WARNING...AMZ031. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER