000 AGXX40 KNHC 221857 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 255 PM EDT MON OCT 22 2012 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... HIGH PRES RIDGE OVER THE NE U.S. EXTENDS THROUGH THE GULF OF MEXICO WITH MODERATE TO FRESH EASTERLY FLOW TURNING TO MODERATE SLY RETURN W OF 94W. HIGH PRES FORECAST TO MOVE E WITH THE PRES GRADIENT WEAKENING OVER THE NW GULF TUE ALLOWING WINDS TO DECREASE TO 10-15 KT. AS T.D. EIGHTEEN MOVES NORTHWARD OVER THE CARIBBEAN PRES GRADIENT INCREASES OVER THE ERN GULF WITH WINDS INCREASING TO 15-20 KT...TO 25 KT IN THE FLORIDA STRAITS TUE AND WED WITH SEAS BUILDING TO 6 FT...AND UP TO 9-11 FT IN THE STRAITS OF FLORIDA TUE AND WED IN MAXIMIZED COUNTER-CURRENT FLOW. AS FORECAST T.S. TRACKS OVER ERN CUBA THU AND OVER THE BAHAMAS FRI WINDS BACK TO NE AT THE SAME SPEEDS THU AND FRI WITH COUNTER-CURRENT SEAS DROPPING OFF IN THE STRAITS OF FLORIDA. AS SYSTEM PULLS FURTHER AWAY SAT WINDS BACK FURTHER INTO NW TO N YET STILL MAINTAINING 20 KT DUE TO THE INCREASING SIZE OF THE CIRCULATION. MEANWHILE THE FIRST SIGNIFICANT COLD FRONT OF THE SEASON ENTERS THE FAR NW GULF FRI EVENING AND EXTENDS FROM THE FL PANHANDLE TO 25N92W TO W BAY OF CAMPECHE WITH STRONG NLY WINDS OF 20-30 KT. GIVEN THE CAA WOULD NOT BE SURPRISED TO SEE BRIEF GALES IN GMZ017...W-CENTRAL GULF ZONE ON SAT. GRIDS WILL NOT REFLECT THIS YET SINCE IT IS OUT AT DAY 5 AND THERE IS TIME TO ASSESS FUTURE MODEL RUNS. SW N ATLC S OF 31N W OF 65W... COLD FRONT EXTENDS FROM 31N60W THEN BECOMES A DIFFUSE STATIONARY FRONT FROM 27N63W TO THE CENTRAL BAHAMAS. THE FRONT WASHES OUT TONIGHT AND TUE. HIGH PRES BUILDS BEHIND THE FRONT WITH NE TO E WINDS INCREASING TO 20 KT ACROSS THE W HALF OF THE AREA THIS EVENING AS HIGH PRES MOVES INTO THE EASTERN U.S. AS T.D. EIGHTEEN MOVES NORTHWARD OVER THE CARIBBEAN PRES GRADIENT INCREASES FURTHER WITH E WINDS OF 20-25 KT...AND 30 KT OVER THE SRN BAHAMAS ON WED. THE CURRENT FORECAST TRACK OF T.D. EIGHTEEN BRINGS THE CENTER ACROSS E CUBA AND EMERGES INTO THE SW N ATLC LATE THU WITH AN EXPANDING WIND FIELD. THE SYSTEM IS FORECAST TO TRANSITION TO A LARGE SUBTROPICAL CYCLONE BY SAT NE OF THE CENTRAL BAHAMAS WITH THE RESULTING WIND FIELDS AFFECTING THE ENTIRE SW N ATLC ZONES. THE LARGE WIND FIELD COUPLED WITH A AN INITIAL VERY LONG EASTERLY FETCH WILL RESULT IN DANGEROUS SEAS OVER A VAST AREA WITH WIDESPREAD MARINE IMPACTS EXPECTED. THE ENSUING SLOW MOVEMENT OF THE CYCLONE WILL ALSO PROLONG THE ADVERSE IMPACTS OVER THE AREA BEYOND SAT. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... MAJOR PLAYER IS NOW NEWLY FORMED TROPICAL DEPRESSION EIGHTEEN ...1003 MB...CENTERED NEAR 13.5N78.5W WILL DRIFT W THIS EVENING THEN MOVE NORTHWARD OVER JAMAICA WED THEN LIFT FURTHER N OVER E CUBA THEN INTO THE SW N ATLC. EVEN AS SYSTEM LIFTS NWD INTO THE SW N ATLC A BROAD SW FETCH CONTINUES ACROSS THE CENTRAL CARIBBEAN THU INTO FRI WITH REVERSE SW WINDS THROUGH THE ATLANTIC PASSAGES PERSISTING INTO SAT. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .TROPICAL STORM WARNING...AMZ021 AND AMZ031. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER COBB