000 AGXX40 KNHC 040645 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 245 AM EDT TUE SEP 4 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. UPPER LEVELS... WEAK TROUGH FROM 31N67W TO N CUBA AND MID-UPPER LEVEL ANTICYCLONE CENTERED AT 23N67W MAINTAIN MODERATE TO STRONG SUBSIDING AIR MASS OVER MOST OF SW N ATLC. ONLY SURFACE TROUGH FROM 31N76W TO 27N80W PROVIDES SOME LOW LEVEL MOISTURE ALONG ITS BOUNDARY. UPSTREAM RIDGE OVER GULF OF MEXICO AND EXTREME NWRN CARIBBEAN SEA MAINTAINS BLOCKING EFFECT NOT ALLOWING HURRICANE FELIX TO GAIN LATITUDE AND CONTINUE IN MORE WLY COURSE. ERN HALF OF CARIBBEAN BASIN ALSO UNDER DRY SUBSIDING AIR MASS. SURFACE... HURRICANE FELIX...A CATEGORY FOUR CYCLONE...CONTINUES HEADING W AT 17 KT AND SHOULD BE MAKING LANDFALL EARLY MORNING TUE NEAR THE NICARAGUA-HONDURAS BORDER. SEE NHC FORECAST FOR DETAILS ABOUT HURRICANE FELIX TRACK AND INTENSITY FORECAST. WIND AND SEA CONDITIONS SHOULD QUICKLY IMPROVE OVER WRN CARIBBEAN LATE TUE AND WED AS CENTRAL ATLC SURFACE RIDGE RETREATS E FORCED BY TROUGH MENTIONED IN UPPER LEVEL PARAGRAPH. TRPCL WAVE ENTER ERN CARIBBEAN TONIGHT WITH STRONG NE WIND WITHIN 120 NM W OF AXIS AND MODERATE SE WIND E OF AXIS. LOW PRES 1011 MB...POSSIBLE TROPICAL CYCLONE WITHIN 48 HRS... JUST OFF N FLORIDA COASTAL WATERS WITH TRAILING SURFACE TROUGH TO 27N80W WILL DRIFT E THEN LOOP IN PLACE JUST N OF FORECAST WATERS. EXPECT HIGHER WIND AND SEAS WITHIN 240 NM OF LOW PRES CENTER IF SYSTEM GETS BETTER ORGANIZED. GULF OF MEXICO WATERS REMAIN UNDER WEAK PRES PATTERN AS DOMINATING RIDGE IS WEAKENED BY LOW PRES OFF FLORIDA COAST. BAY OF CAMPECHE COULD FEEL EFFECTS OF HURRICANE FELIX BY THU ALTHOUGH SYSTEM WOULD BE SIGNIFICANTLY WEAKENED BY ITS LANDFALL BY THEN. WARNINGS... ATLANTIC... NONE. CARIBBEAN... AMZ082 AMZ084...HURRICANE WARNING. GULF OF MEXICO... NONE. FORECASTER WALLY BARNES