000 AGXX40 KNHC 281942 RRA MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST SAT NOV 28 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... A HIGH PRES RIDGE CENTERED OVER THE CENTRAL GULF WILL SHIFT E AND WEAKEN TOMORROW AS A COLD FRONT APPROACHES THE TEXAS COAST. SOUTHERLY FLOW TO 20 KT IS EXPECTED BEGIN LATE TONIGHT IN THE NW GULF AHEAD OF THE COLD FRONT. AS THE COLD FRONT CROSSES THE COAST INTO THE NW GULF MON...A SURFACE WAVE WILL DEVELOP ALONG THE BOUNDARY. THE MODELS STILL DIFFER WITH THE TRACK AND INTENSITY OF THE LOW...BUT ARE COMING INTO BETTER AGREEMENT ON A TRACK THAT MOVES THE SURFACE LOW NE INTO THE MISSISSIPPI AND TENNESSEE VALLEYS WED. THE GFS IS AMONG THE FASTER SOLUTIONS TO CARRY THE LOW AND COLD FRONT EASTWARD INTO THE CENTRAL GULF...SO ADJUSTMENTS WERE MADE TOWARD A SLOWER SOLUTION WITH THE COLD FRONT THAN THE GFS. IN ADDITION...A BOTH THE GFS AND ECMWF ARE HINTING AT A CENTRAL GULF GALE EVENT WED IN THE SOUTHERLY FLOW AHEAD OF THE FRONT. NEITHER THE 12O00 UTC GEFS OR THE 0900 UTC SREF SHOW ANY SIGNIFICANT CHANCE OF GALES. FOR NOW...A SOLID AREA OF 30 KT WINDS IS EXPECTED IN THE GULF LATE TUE THROUGH WED...BUT THERE IS NOT ENOUGH CONFIDENCE IN THE FORECAST TO RAISE A GALE FLAG. CARIBBEAN AND TROPICAL N ATLC... THE STALLED AND DISSIPATING FRONTAL BOUNDARY CURRENTLY OVER THE NW CARIBBEAN IS STILL BRINGING 20 TO 25 KT N TO NE FLOW BEHIND THE FRONT ACCORDING TO THE 1520 UTC ASCAT PASS. THE FRONT IS FORECAST TO CONTINUE TO SLOWLY SHIFT EASTWARD OVER THE NEXT FEW DAYS AND DISSIPATE. THE MODELS ARE IN REASONABLE AGREEMENT ON WINDS AND SEAS DIMINISHING BELOW 20 KT/8 FT OVERNIGHT. THEN...LOOK FOR WINDS TO SHIFT MORE SOUTHERLY IN ADVANCE OF THE STRONG COLD FRONT IN THE GULF OF MEXICO EARLY NEXT WEEK. THIS FRONT IS EXPECTED TO PUSH THROUGH THE YUCATAN CHANNEL ON THU. FARTHER SOUTH...THE PRES GRADIENT N OF THE COLOMBIAN LOW OVER THE CENTRAL CARIBBEAN HAS DECREASED DUE TO THE FRONTAL BOUNDARY STRETCHED OVER THE SOUTHERN SW N ATLC ZONE. THE ASCAT PASSES FROM 1340 AND 1522 UTC SHOW WINDS IN THE 15 TO 20 KT RANGE OVER THE SOUTHWESTERN AND SOUTHEASTERN CARIBBEAN. OBSERVATIONS BETWEEN THESE PASSES FROM SHIPS PCKU AND PDKK SHOW WINDS AROUND 20 KT NEAR THE COAST OF COLOMBIA. EXPECT THE PATTERN TO REMAIN RELATIVELY STAGNANT HERE OVER THE NEXT FEW DAYS...WITH HIGHEST WINDS TO 25 KT IN THE MORNING HOURS NEAR THE COAST OF COLOMBIA. BY MID WEEK...BUILDING HIGH PRES OVER THE CENTRAL N ATLC SHOULD BUILD THE PRES GRADIENT OVER THE EASTERN CARIBBEAN AND TROPICAL N ATLC...WITH TRADES BUMPING UP IN THESE REGIONS ABOVE 20 KT. STARTING MON...THE TROPICAL N ATLC WILL SEE WAVE HEIGHTS INCREASE ABOVE 8 FT IN THE NW SWELL ASSOCIATED WITH THE COLD FRONT PASSING N OF THE ZONE. THIS WEAK FRONTAL BOUNDARY WILL APPROACH THE NE CARIBBEAN ISLANDS TOMORROW AND MAY ENHANCE THE CHANCE OF CONVECTION AS IT POOLS LOW LEVEL MOISTURE ALONG THE DISSIPATING BOUNDARY THE NEXT FEW DAYS. SW N ATLC... THE 1518 AND 1338 UTC ASCAT PASSES SHOWS W TO NW WINDS IN THE 20 TO 25 KT RANGE NOW SHIFTING E WITH THE COLD FRONT TO THE AREA N OF 30N E OF 72W. THESE WINDS SHOULD DIMINISH OVERNIGHT AS WELL AS THE NW SWELL IN THE 8 TO 14 FT RANGE OVER THE EASTERN WATERS. THE DISSIPATING LOW LEVEL BOUNDARY WILL REMAIN OVER THE SE PORTION OF THE ZONE SUN. THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE TRACK OF THE HIGH PRES SYSTEM MOVING E IN THE WAKE OF THE COLD FRONT. THE MODELS ARE COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT COLD FRONT MOVING INTO NW WATERS TUE. THE FORECAST BECOMES MORE UNCERTAIN ON WED/THU AS THE NEXT COLD FRONT APPROACHES. LOOK FOR SW WINDS TO PICK UP AHEAD OF THE FRONT WED...WITH GALES POSSIBLE THU. THE GEFS SHOW UP TO A 50 PERCENT CHANCE OF GALE FORCE WINDS OVERNIGHT WED NIGHT INTO THU MORNING. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. $$ FORECASTER SCHAUER