000 AGXX40 KNHC 171922 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 200 PM EST SAT NOV 17 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST N ATLC S OF 31N W OF 55W. GULF OF MEXICO... A SURFACE TROUGH IS IN THE FAR SW GULF OF MEXICO. OTHERWISE ANTICYCLONIC FLOW COVERS THE GULF AROUND HIGH PRES CENTERED OVER THE U.S. OHIO VALLEY WITH A RIDGE EXTENDING TO THE SW TO EASTERN TEXAS...AND THEN S INTO NE MEXICO. MAINLY MODERATE NE-E WINDS COVER THE GULF WATERS...EXCEPT FRESH WINDS IN THE NE GULF WHERE THE PRES GRADIENT IS TIGHTER. BUOY OBSERVATIONS INDICATE 3-5 FT SEAS ACROSS THE MAJORITY OF THE BASIN. SCATTERED SHOWERS AND ISOLATED TSTMS CONTINUE OVER THE EASTERN GULF MAINLY E OF 87W NEAR THE BASE OF A MID TO UPPER LEVEL TROUGH. LITTLE CHANGE IN WEATHER CONDITIONS IS FORECAST THROUGH THE MIDDLE OF NEXT WEEK. THE TROUGH WILL LINGER NEAR THE EASTERN MEXICO COAST WHILE THE HIGH SINKS TO THE SW BECOMING CENTERED OVER THE LOWER MISSISSIPPI VALLEY LATE WED. CARIBBEAN SEA AND TROPICAL N ATLC... 1010 MB LOW PRES IS IN THE SW CARIBBEAN NEAR 10.5N78W. THIS LOW WILL REMAIN NEARLY STATIONARY THROUGH EARLY MON...DISSIPATING BY EARLY TUE. OTHERWISE...UNSETTLED WEATHER PERSISTS IN THE CENTRAL CARIBBEAN ON THE E SIDE OF AN UPPER TROUGH AXIS WHICH EXTENDS FROM SOUTH FLORIDA TO ACROSS CENTRAL CUBA TO NEAR THE HONDURAS/ NICARAGUA BORDER. VERY DRY AIR IS BEHIND THE TROUGH IN THE NW CARIBBEAN. MODERATE TRADES DOMINATE THE CARIBBEAN BETWEEN THE LOW IN THE SW CARIBBEAN AND BROAD RIDGING OVER THE SE GULF OF MEXICO AND N CENTRAL ATLC. THE EXCEPTION IS NEAR THE COAST OF NICARAGUA WHERE FRESH TO STRONG NORTHERLY WINDS AND SEAS TO 8 FT ARE PRESENT. THESE STRONGER WINDS ARE THE RESULT OF A TIGHTER PRES GRADIENT BETWEEN THE GULF RIDGING AND THE SURFACE LOW. SEAS ARE PRIMARILY 3-5 FT ACROSS THE BASIN. WITH THE CURRENT SYNOPTIC PATTERN EXPECTED TO CHANGE LITTLE THROUGH THE PERIOD AS SUGGESTED BY THE MODELS...EXPECT THE STRONGER WINDS NEAR THE COAST OF NICARAGUA TO CONTINUE THROUGH WED. IN THE TROPICAL N ATLC...AFTERNOON ASCAT PASSES MISSED THE MAJORITY OF THE OFFSHORE ZONES...ALTHOUGH WINDS FROM 55W EASTWARD WERE NE-E AT 20 KT AND BUOY OBSERVATIONS N OF THE AREA INDICATE EASTERLY 20 KT WINDS AS WELL. MEANWHILE...NE SWELL OF 7-10 FT CONTINUES TO PROPAGATE INTO THE ZONES...MAINLY N OF 10N WITH A LONG NE-E FETCH AROUND N CENTRAL ATLC HIGH PRES. THE HIGH IS FORECAST TO WEAKEN THROUGH MID-WEEK ALLOWING FOR THESE WINDS TO DIMINISH TO 10-15 KT BY LATE MON...THEN TO 5-10 KT TUE AND WED AS THEY VEER TO THE SE-S. THE NE SWELL WILL DECAY AND SUBSIDE TO 5-7 FT MON...AND THEN TO 4-5 FT TUE AND WED. SOUTHWEST N ATLC S OF 31N W OF 55W... A STATIONARY FRONT LAYS ACROSS THE FAR NW PORTION OF THE REGION FROM NEAR 31N76W TO BETWEEN GRAND BAHAMA AND S FLORIDA. A RECENT ASCAT PASSES INDICATED GALE FORCE WINDS OCCURRING N OF 31N W OF THE FRONT WHILE IN-SITU OBSERVATIONS SHOW N-NE 20-25 KT WINDS S OF 31N W OF THE FRONT. A LONG AND PERSISTENT NE FETCH WILL CONTINUE TO PUMP IN NE SWELL TO 10 FT W OF THE FRONT AND VERY ACTIVE CONVECTION WILL REMAIN UNDER UPPER DIFFLUENCE ALOFT PRIMARILY W OF THE FRONT. A SURFACE TROUGH EXTENDS FROM E OF BERMUDA NEAR 31N63W TO 23N66W. ACTIVE CONVECTION IS ALSO PRESENT ACROSS THE OFFSHORE WATERS E OF ABOUT 75W...WHICH IS E OF THE MID TO UPPER LEVEL TROUGH AXIS DESCRIBED ABOVE. THE SURFACE TROUGH WILL LINGER ACROSS THE SAME GENERALLY AREA THROUGH THE EARLY PART OF THE WEEK WITH MAINLY LIGHT TO MODERATE WINDS NEAR THIS SURFACE FEATURE. THE STATIONARY FRONT IS FORECAST TO BE PULLED WESTWARD AS A WARM FRONT DURING THE NEXT 24 HORUS BY A MID TO UPPER LOW OVER THE SE U.S...STALLING OVER THE WESTERN WALL OF THE GULF STREAM THROUGH EARLY TUE...THEN WILL PUSH BACK TO THE E-SE AS A COLD FRONT LATE TUE THROUGH WED AS AN AREA OF LOW PRES DEVELOPS JUST N OF 31N...MOVING EASTWARD THROUGH THE WEEK DRAGGING THE TRAILING FRONT. THE COLD FRONT IS FORECAST TO EXTEND FROM 31N72W TO THE CENTRAL BAHAMAS EARLY WED...THEN FROM 31N68W TO EASTERN CUBA EARLY THU WITH FRESH TO STRONG NORTHERLY WINDS BEHIND IT. FRESH TO STRONG SW WINDS WILL PRECEDE THE FRONT N OF 28N...WITH MODERATE SOUTHERLY FLOW S OF 28N E OF THE FRONT THROUGH AMZ127. A BLEND OF THE PREVIOUS FORECAST ALONG WITH THE NEW GFS AND ECMWF MODEL RUNS WAS USED FOR THE AFTERNOON GRIDDED PACKAGE. 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 LEWITSKY