000 AGXX40 KNHC 180557 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 AM EDT WED JUL 18 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. THE GFS AND NOGAPS MODELS SHOW A SURFACE RIDGE TO STAY ACROSS THE NORTHERN GULF OF MEXICO. THIS RIDGE WILL COMBINE WITH LOWER PRESSURES IN SOUTHERN MEXICO IN ORDER TO KEEP 15 TO 20 KT WINDS IN THE SW GULF THROUGH FRIDAY...AND THEN DECREASE DURING THE WEEKEND. A SURFACE TROUGH IS ALONG A LINE FROM SOUTHEASTERN GEORGIA INTO NORTHEASTERN FLORIDA...SOMETIMES SLIPPING EVER SO SLIGHTLY INTO THE NORTHEASTERN GULF OF MEXICO WATERS DURING THE ENTIRE FORECAST PERIOD. THE LOWER SURFACE PRESSURES FROM SOUTHERN GEORGIA INTO FLORIDA AND POSSIBLY NORTHEASTERN GULF WATERS BECOMES MORE AND MORE PROMINENT STARTING ON SATURDAY MORNING AND CONTINUING UNTIL THE END OF THE FORECAST PERIOD. THE ATLANTIC OCEAN RIDGE COMBINED WITH LOW PRESSURE IN NORTHERN COLOMBIA WILL MAINTAIN AT LEAST 20 KT TRADEWINDS IN THE CARIBBEAN SEA SOUTH OF 18N EAST OF 80W. THE WINDS ARE EXPECTED TO DECREASE SOME BY FRIDAY AS THE ATLANTIC OCEAN RIDGE WEAKENS... BUT THEN PICK UP AGAIN TO AT LEAST 20 KT FOR SATURDAY AND SUNDAY. THE ATLANTIC OCEAN RIDGE REMAINS ALONG 30N/31N UNTIL LATE THURSDAY WHEN ITS WESTERNMOST POSITION ALONG 80W STARTS TO MOVE GRADUALLY MORE AND MORE EASTWARD...AS THE SOUTHEASTERN U.S.A. COLD FRONT STARTS TO MOVE EASTWARD INTO THE ATLANTIC OCEAN. THE WESTERNMOST EXTENT OF THE RIDGE EVENTUALLY REACHES 73W/74W BY SUNDAY. IT APPEARS TO ME THAT THE MODELS SUGGEST A TROUGH FROM SOUTHEASTERN GEORGIA INTO NORTHEASTERN FLORIDA DURING THE ENTIRE FORECAST PERIOD. THIS TROUGH...POSSIBLY BECOMING A COLD FRONT...EVENTUALLY MOVES EASTWARD INTO THE ATLANTIC OCEAN WATERS SATURDAY INTO SUNDAY. SOUTHERLY 20 KT WINDS START LATE THURSDAY NORTH OF 30N WEST OF 78W. THIS WIND REGIME CONTINUES TO BE NORTH OF 30N...SPREADING EASTWARD TO 75W AND AT TIMES TO 70W...BUT ALWAYS NORTH OF 30N. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER MT