000 AGXX40 KNHC 271944 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 145 AM EST FRI NOV 27 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... NORTHEASTERLY FLOW ACROSS THE EASTERN GULF AND THE RESIDUAL NW TO N FLOW OVER 20 KT IN THE FAR SW GULF IS QUICKLY SUBSIDING AFTER THE FRONTAL PASSAGE YESTERDAY. SHIP A8IO4 IN THE STRAITS OF FL NEAR THE CUBAN COAST AT 23N83W WAS STILL REPORTING WINDS TO 25 KT AND SEAS OF 10 FT AROUND 1800 UTC AND THE 1540 UTC ASCAT PASS ALSO SUPPORTED A SMALL AREA OF 20 KT IN THE FAR SW GULF. THESE LINGERING WINDS WILL DIMINISH OVER NIGHT AND SHIFT EASTERLY AS THE HIGH PRES RIDGE OVER THE WESTERN GULF PASSES TO THE NORTHEAST....REACHING NORTH FLORIDA LATE SAT WITH RIDGE OVER THE NORTHEAST GULF OF MEXICO SUN. RIDGE WILL WEAKEN MON AS A COLD FRONT MOVES OFF THE TEXAS COAST AND DEVELOPS A SURFACE WAVE IN THE WESTERN GULF TUE. THE MODELS ARE IN GOOD AGREEMENT UNTIL THIS POINT WHEN THE MODEL DIFFER CONSIDERABLY WITH THE TRACK AND INTENSITY OF THE LOW. THE GFS AND ECMWF GENERALLY AGREE ON A SLOWER SOLUTION THAN THE OTHER MODELS CARRYING THE FRONT SOUTHEASTWARD INTO THE EASTERN GULF AND A BLEND OF THEIR SOLUTIONS AND LOW POSITIONS WAS USED FOR THE FORECAST. IN ADDITION...A NUMBER OF THE MODELS ARE HINTING AT A GALE EVENT IN THE SW GULF ZONE TUE AS THE SURFACE LOW DEVELOPS. THE GEFS IS ONLY SHOWING A 10-30 PERCENT CHANCE OF GALES BRIEFLY TUE MORNING. FOR NOW...THERE IS NOT ENOUGH CONFIDENCE IN THE FORECAST TO RAISE A GALE FLAG. CARIBBEAN AND TROPICAL N ATLC... THE SLOW MOVING FRONTAL BOUNDARY CURRENTLY OVER THE NW CARIBBEAN IS BRINGING 20 TO 25 KT N TO NE FLOW BEHIND THE FRONT ACCORDING TO THE 1540 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 BY SUN. THEN...LOOK FOR WINDS TO SHIFT MORE SOUTHERLY IN ADVANCE OF THE STRONG COLD FRONT IN THE GULF OF MEXICO EARLY NEXT WEEK. FARTHER SOUTH...THE PRES GRADIENT BETWEEN THE 1026 MB HIGH RIDGE OVER THE WESTERN GULF OF MEXICO AND THE 1006 MB COLOMBIAN LOW CONTINUES TO SUPPORT WINDS IN THE 25-30 KT RANGE AS SEEN IN SHIP OBSERVATIONS THROUGH THE DAY INCLUDING 3EBL5 NEAR 16N81W AT 1800 UTC. THE 1402 UTC ASCAT PASS SHOWS AT LEAST 25 KT WINDS NEAR THE COAST OF COLOMBIA AS WELL. LOOK FOR WINDS REMAIN STRONG AS THE HIGH PRES MOVES IN BEHIND THE SW N ATLC COLD FRONT. THIS HIGH PRES WILL BE CHASED E EARLY NEXT WEEK BY THE COLD FRONT ADVANCING THROUGH THE GULF OF MEXICO. FARTHER E OVER THE TROPICAL ATLC...A SLOW MOVING DEEP LAYER TROUGH ALONG 50-55W WILL CONTINUE TO SUPPORT A WEAK SURFACE TROUGH S OF 20N INTO THE WEEKEND...AND TRADE WINDS OVER 20 KT AND MUCH OF THE CONVECTION ASSOCIATED WITH THE SYSTEM WILL MAINLY BE CONFINED E OF THIS TROUGH KEEPING CONDITIONS RELATIVELY TRANQUIL OVER THE LESSER ANTILLES THROUGH THE WEEKEND. THE WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE FRONT CURRENTLY OVER THE SW N ATLC WILL APPROACH THE NE CARIBBEAN ISLANDS EARLY NEXT WEEK AND MAY ENHANCE THE CHANCE OF CONVECTION. SW N ATLC... THE 1358 UTC ASCAT PASS SHOWS W TO NW WINDS IN THE 25 TO 30 KT RANGE BEHIND A SECONDARY SURGE OF COLD...DRY AIR THAN MOVED IN BEHIND THE MAIN FRONTAL BOUNDARY OVER FORECAST WATERS THIS AFTERNOON. NOW THAT THE UPPER LEVEL TROUGH HAS CAUGHT UP TO THE LEAD SURFACE BOUNDARY THE FRONT WILL PICK UP SPEED...MOVING THROUGH THE REMAINDER OF THE SW N ATLC ZONE BY SAT NIGHT. THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE PASSAGE OF THIS FRONTAL SYSTEM THROUGH THE ZONE AS WELL AS WITH THE TIMING AND TRACK OF THE HIGH PRES SYSTEM IN ITS WAKE. DIFFERENCES ARISE WITH THE TIMING OF THE NEXT COLD FRONT MOVING INTO NW WATERS TUE AND WED. A BLEND OF THE GFS AND ECMWF IS PREFERRED AS EXPLAINED IN THE FIRST SECTION ABOVE. LOOK FOR SW WINDS TO PICK UP AHEAD OF THE FRONT WED...WITH GALES POSSIBLE LATE IN THE DAY. FOR NOW...CONFIDENCE IS LOW IN THE FORECAST AND THE GEFS SHOWS ANY POSSIBILITY OF GALE FORCE WINDS N OF 31N. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. $$ FORECASTER SCHAUER