000 AGXX40 KNHC 241835 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 135 PM EST FRI DEC 24 2010 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... RADAR SHOWS A STRONG LINE OF THUNDERSTORMS PASSING THROUGH CENTRAL TEXAS AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO MOVE OFFSHORE BEFORE SUNRISE CHRISTMAS DAY. AN AREA OF LOW PRES IS FORECAST TO SKIRT THROUGH THE NORTHERN GULF COASTAL PLAIN SAT AND THE 12Z GFS BROADENS THIS AREA OF LOW PRES MORE COMPARED TO ITS LAST TWO RUNS AS THE LOW MAKES ITS WAY THROUGH THE CENTRAL AND EASTERN GULF. THE 00Z ECMWF HAS ALSO TRENDED TOWARD A MORE STRUNG OUT AREA OF LOW PRES COMPARED TO RUNS FROM EARLIER IN THE WEEK. A BLEND OF THE GFS AND ECMWF WAS USED FOR THE FORECAST. BOTH MODELS KEEP WINDS JUST BELOW GALE FORCE WITH THE SYSTEM. RELIED PRIMARILY ON THE MWW3 FOR WAVE HEIGHT GUIDANCE BUT ATTEMPTED TO CORRECT FOR THE BIAS IN THE MWW3 TO HOLD ONTO HIGHER SEAS TOO LONG AFTER THE WINDS HAVE DIMINISHED. CARIBBEAN AND TROPICAL N ATLC... SURFACE OBSERVATIONS AND THE 1154 UTC WINDSAT PASS SHOW THE STRONGEST WINDS IN THE CARIBBEAN CONFINED BETWEEN 75W AND 83W WHERE THE PRES GRADIENT IS STRONGEST BETWEEN HIGHER PRES OVER THE YUCATAN CHANNEL BEHIND THE FRONT JUST N OF THE GREATER ANTILLES AND LOWER PRES TO THE S AND E OVER S AMERICA AND ASSOCIATED WITH THE FRONT. THIS GRADIENT WILL SHIFT E WITH THE FRONT TOMORROW...MAKING FOR A LONGER FETCH AND MORE WIDESPREAD SEAS IN THE 7-8 FT RANGE OVER THE CENTRAL AND SW CARIBBEAN. IN ADDITION...N SWELL BEHIND THE FRONT WILL MOVE THROUGH THE N FACING ATLC PASSAGES INTO THE EASTERN CARIBBEAN SAT. THE AFOREMENTIONED COLD FRONT IN THE GULF OF MEXICO SHOULD MOVE THROUGH THE YUCATAN CHANNEL SUN AND N WINDS TO 25 KT ARE EXPECTED TO RAPIDLY FILTER S THROUGH THE WESTERN CARIBBEAN WHILE WINDS DIMINISH OVER THE EASTERN AND CENTRAL CARIBBEAN. THE ECMWF AND 12Z GFS ARE NOT TERRIBLY DIFFERENT HERE. THE LEADING EDGE OF THE COLD FRONT TRAVELS THROUGH THE WINDWARD PASSAGE MON AND THE MONA AND ANEGADA PASSAGES TUE. WINDS WILL LIKELY BE INTENSIFIED AS THEY FUNNEL THROUGH THE PASSAGES...WITH THE GFS AND ECMWF SHOWING WINDS TO JUST BELOW GALE FORCE IN THE MONA PASSAGE AND OFF THE SE COAST OF THE DOMINICAN REPUBLIC BY SUNSET TUE. SW N ATLC... UNFORTUNATELY...A WINDSAT OUTAGE PREVENTED THE RECEIPT OF A PASS OVER THE EASTERN PORTION OF THE ZONE THIS MORNING...BUT BUOY OBS JUST N AND E OF THE ZONE...RESPECTIVELY...SHOWED WINDS IN THE 25-30 KT RANGE. THESE WINDS WILL DIMINISH OVERNIGHT AS THE COLD FRONT MOVES AWAY FROM THE AREA. THE CLOUD BAND ASSOCIATED WITH THE COLD FRONT CURRENTLY OVER S WATERS IS BEGINNING TO BECOME DIFFUSE AND SURFACE OBSERVATIONS SHOW WINDS BECOMING MORE UNIFORM OVER S WATERS. THIS WEST EDGE OF THE FRONT WILL DISSIPATE WHILE THE REMAINDER MOVES E OF THE AREA TONIGHT. A STRONGER COLD FRONT WILL MOVE INTO NW WATERS BEFORE SUNRISE SUN. AS ALLUDED TO IN THE GULF OF MEXICO SECTION...THE GENERAL MODEL TREND HAS BEEN TOWARD A BROADER AREA OF LOW PRES MOVING FROM THE NE GULF INTO NW PORTIONS OF THIS ZONE. THE 00Z ECMWF CARRIES THE LOW MORE RAPIDLY TO THE NE AWAY FROM THIS ZONE THAN THE 12 GFS...BUT IS SLOWER TO MOVE THE FRONT THROUGH S FLORIDA SUN MORNING. GALE FORCE WINDS ARE FORECAST WITHIN 210 NM ON EITHER SIDE OF THE FRONT SUN THROUGH MON MORNING. WHILE THE GFS AND ECMWF HAVE TIMING DIFFERENCES...THEY AGREE ON THE DEVELOPMENT OF GALE FORCE WINDS. BY LATE MON...THE GFS HAS TRENDED TOWARD KEEPING WINDS TO 30 KT OVER THE N PORTION OF THE ZONE LONGER THAN ITS 00Z RUN. ALOFT...IT CARRIES MORE AMPLIFIED TROUGHING OVER THE ZONE AS NEW SHORTWAVE ENERGY MOVES INTO THE BACKSIDE OF THE TROUGH. THIS IS A TREND TOWARD THE MORE CONSISTENT ECMWF SOLUTION. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER