000 AGXX40 KNHC 201843 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 200 PM EST TUE NOV 20 2012 UPDATED TO INCLUDE MENTION OF OSCAT PASS IN GULF OF MEXICO SECTION 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... WEAK SURFACE TROUGH ALONG 93W S OF 24N MOVES W OUT OF BASIN LATE TONIGHT WITH ITS ASSOCIATED MODERATE TO FRESH NE BREEZE AND 4-5 FT SEAS W OF AXIS. GENTLE TO MODERATE NE TO E BREEZE ELSEWHERE IN BASIN AS HIGH PRES CENTER OVER SE STATES EXTEND RIDGE ACROSS N GULF COASTAL WATERS. SEAS REMAIN LESS THAN 4 FT. UPPER LEVEL RIDGE OVER ENTIRE BASIN CURTAIL CLOUD VERTICAL DEVELOPMENT KEEPING LOW STRATIFIED ALONG W SIDE OF SURFACE TROUGH AND E OF 86W. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... MODERATE TO FRESH N-NE WINDS W OF JUST DISSIPATED SURFACE TROUGH W OF 80W CONVERGING WITH MODERATE EASTERLY TRADES SUPPORT AREA OF SCATTERED MODERATE TO STRONG CONVECTION S OF 15N ENHANCED BY SLIGHT DIVERGING FLOW ALOFT. ELSEWHERE...CENTRAL ATLC RIDGE... WEAKENED BY ATLC COLD FRONT...EASED PRES GRADIENT OVER CARIBBEAN E OF 80W ALLOWING SEAS TO SUBSIDE UNDER MODERATE E TRADES. SOUTHERN TIP OF ATLC COLD FRONT ENTERS TROPICAL N ATLC LATER TODAY BRINGING ISOLATED MODERATE TSTMS N OF 20N W OF 60W. FRONT EXPECTED TO DISSIPATE LATE TONIGHT WITH NO SIGNIFICANT IMPACT ON BASIN. SECOND COLD FRONT APPROACHING LATE IN FORECAST PERIOD EXPECTED TO BRING 6-8 FT N SWELLS INTO REGION. SW N ATLC W OF 55W... COMPLEX LOW PRES CENTERS OVER NW PART OF BASIN EXPECTED TO DISSIPATE BY LATE TONIGHT WITH THEIR ASSOCIATED COLD FRONTS OUT OF REGION. MORE INTENSE DEEP LAYER CYCLONE AT 35N65W EXPECTED TO DRIFT S OF 31N WITH ASSOCIATED COLD FRONT BRINGING STRONG N WINDS AND 8-10 FT SEAS N OF 25N W OF 73W WED AND THU. MODEL GUIDANCE SOLUTIONS IN AGREEMENT WITH THIS SCENARIO. FURTHER E...WEAKENED COLD FRONT EXTENDS FROM 27N65W TO 25N73W. WINDS ARE DIMINISHING TO A MODERATE BREEZE AND SEAS SUBSIDING BELOW 6 FT LATER TODAY AND TONIGHT. ANOTHER BLAST OF COLD AIR FOLLOWS LATER IN FORECAST PERIOD WITH STRONG TO NEAR GALE N WINDS WITH 13 FT SEAS ENTERING NW CORNER OF BASIN THU AND SPREADING SE THROUGH SW N ATLC N OF 22N BY SAT. MODEL DIFFER IN INTENSITY AND POSITION OF LOW PRES CENTER...BUT REACHING GALE FORCE WINDS IN THE NORTHERN FRINGES OF ZONE FOR SHORT PERIODS MAY NOT BE OUT OF THE QUESTION. SEA HEIGHTS MAY REACH 16-17 FT. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER WALLY BARNES