000 AGXX40 KNHC 050659 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 AM EDT FRI NOV 5 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... NUMEROUS BUOY REPORTS IN THE NW GULF CONFIRMED GALE CONDITIONS THU AND BUOY 42055 IN THE SW GULF ZONE ALSO HAD GALE FORCE WINDS AND SEAS AS HIGH AS 21 FT. WHILE THE WINDS HERE WERE CONSISTENT WITH THE GFS FORECAST...WITH WAVE FORECAST FROM THE MWW3 WAS UNDERDONE BY AT LEAST 3 FT. GALES ARE EXPECTED TO CONTINUE THROUGH THE EARLY MORNING HOURS IN THE FAR SW GULF. HOWEVER...THE 21Z SREFS HAVE BACKED OFF ON EXTENDING THE GALE MUCH PAST 12Z. HIGH PRES PASSING N OF THE AREA TAKES CONTROL OF THE GULF OVER THE WEEKEND...WITH WINDS DIMINISHING IN THE WESTERN GULF AND SHIFTING SOUTHEASTERLY IN THE NW GULF WHILE THE PRES GRADIENT REMAINS STRONG OVER THE EASTERN GULF WITH WINDS AROUND 20 KT BETWEEN THE SURFACE HIGH AND TOMAS TO THE SE OF THE AREA. UNCERTAINTY WITH THE TRACK AND INTENSITY OF TOMAS...AND IN TURN THE STRENGTH OF THE PRES GRADIENT OVER THE EASTERN GULF...REMAINS HIGH. THE MODELS HINT AT 20 KT SOUTHEASTERLY RETURN FLOW OFF THE COAST OF S TX AND NE MEXICO TUE IN ADVANCE OF THE NEXT TROUGH MOVING INTO THE PLAINS. CARIBBEAN SEA... THE CONVECTION ASSOCIATED WITH TOMAS HAS BECOME CONSIDERABLY MORE ORGANIZED OVERNIGHT. THE FORECAST ISSUED AT 03Z CALLS FOR TOMAS TO CONTINUE NE THROUGH THE WINDWARD PASSAGE...INTENSIFYING TO A HURRICANE BY SUNRISE. HEAVY RAIN IS EXPECTED TO FALL WITH TOMAS OVER EASTERN JAMAICA...EASTERN CUBA...AND HAITI. THE WINDWARD FACING SLOPES OF MOUNTAINS WILL LIKELY SEE THE HIGHEST RAINFALL TOTALS...BUT LIFE THREATENING FLASH FLOODS AND MUDSLIDES WILL BE POSSIBLE OVER ALL AREAS OF MOUNTAINOUS TERRAIN EXPECTING HEAVY RAIN FROM TOMAS. FARTHER W...THE FIRST STRONG COLD FRONT OF THE SEASON HAS PLOWED INTO THE NW CARIBBEAN. WINDS COULD BRIEFLY REACH GALE FORCE IN THE YUCATAN CHANNEL TODAY BEHIND A SECONDARY COLD FRONT EXPECTED TO REACH THE NW CARIBBEAN EARLY FRI MORNING. N WINDS ARE EXPECTED TO REMAIN AT OR ABOVE 20 KT OVER THE ENTIRE NW CARIBBEAN ZONE AND THE EASTERN HALF OF THE SW CARIBBEAN THROUGH THE WEEKEND. UNCERTAINTY IS HIGHER IN THE EASTERN CARIBBEAN WHERE THE 00Z GFS AND ECMWF LEAVE BEHIND SOME SHORTWAVE ENERGY ASSOCIATED WITH TOMAS AND ALLOW IT TO INTERACT WITH ENERGY ASSOCIATED WITH THE TROUGH CURRENTLY OVER THE WINDWARD ISLANDS. THESE MODELS SHOW DIFFERING DEGREES OF DEVELOPMENT WITH THIS INTERACTING ENERGY AND ALSO ARE DIFFERENT WITH THE TIMING AND INTENSITY OF TOMAS. FOR NOW...LEANING TOWARD THE GFS SOLUTION AS IT HAS A REASONABLE HANDLE ON TOMAS. IT SHOWS A FORECAST CLOSER TO THE OFFICIAL FORECAST THAN THE ECMWF. THE ECMWF ALSO IS THE STRONGEST OF ALL THE GLOBAL GUIDANCE WITH THE INTERACTING ENERGY IN THE E CARIBBEAN. FEAR IT MAY BE OVERDONE. TROPICAL N ATLC... THE MODELS ARE IN AGREEMENT ON AMPLIFYING THE UPPER PATTERN OVER THE CENTRAL ATLANTIC OVER THE NEXT 24 HOURS. THE TROUGH CURRENTLY CENTERED NEAR 40W WILL DIG S AND PINCH OFF A LOW ALOFT THAT WILL RETROGRADE N OF THE TROPICAL N ATLC ZONE. THE ECMWF HAS TRENDED TOWARD THE MODEL CONSENSUS WHICH INCLUDES THE MORE CONSISTENT GFS FORECAST. THE GFS IS ALSO REASONABLY CLOSE TO THE OFFICIAL NHC FORECAST FOR TOMAS UNTIL 12Z SUN WHEN IT DIVERGES TO THE SE TOWARD THIS UPPER LOW. THIS MORE SE TRACK BRINGS STRONGER WINDS INTO THE NORTHERN PORTION OF THE ZONE THAN WHAT WOULD BE EXPECTED BASED ON THE OFFICIAL FORECAST...SO ADJUSTMENTS WERE REQUIRED SUN THROUGH TUE TO REFLECT WEAKER WINDS FROM THE S. SW N ATLC... THE GFS ONLY SHOWS A VERY SMALL AREA AHEAD OF THE FRONT MOVING TO GALE FORCE WINDS AHEAD OF THE FRONT FOR ONE PERIOD TODAY AND THE ENSEMBLES DO NOT SHOW SIGNIFICANT SUPPORT FOR A GALE WARNING. MAJOR CHANGES TO THE GFS ARE NECESSARY AFTER 12Z SUN TO STAY IN LINE WITH THE OFFICIAL NHC FORECAST FOR TOMAS WHICH IS FARTHER NW THAN THE GFS. THE MORE NW OFFICIAL FORECAST ALSO SUGGESTS A STRONGER PRES GRADIENT BETWEEN TOMAS AND HIGH PRES OVER THE U.S. WINDS WERE INCREASED IN THE NW PORTION OF THE ZONE EARLY NEXT WEEK COMPARED TO THE GFS AS A RESULT. WARNINGS... ATLC... .HURRICANE WARNING S OF 26N BETWEEN69W AND 75W...AMZ080. CARIBBEAN... .TROPICAL STORM WARNING E OF 76W...AMZ082. .TROPICAL STORM WARNING N OF 16N W OF 72W...AMZ086. GULF OF MEXICO... .GALE WARNING S OF 24N W OF 93W...GMZ082. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER