000 AGXX40 KNHC 171735 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 135 PM EDT WED SEP 17 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO... CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... LATEST SURFACE ANALYSIS REVEALS A NEARLY STATIONARY FRONT EXTENDS FROM THE FLORIDA BIG BEND TO AROUND 26N93W TO 18N94W. SATELLITE PICTURES INDICATE THAT MOST OF THE ASSOCIATED CONVECTION NEAR THE BOUNDARY HAS MARKEDLY DECREASED DURING THE PAST 24 HOURS EXCEPT OVER THE SOUTHWEST GULF WATERS...WHERE MODELS SHOW STRONGER LOW-LEVEL CONVERGENCE. BUOY...AN OCCASIONAL SHIP REPORT...AND A 1220 UTC QUIKSCAT PASS SUGGEST THAT STRONG N TO NE WINDS BEHIND THE FRONT ARE NOW CONFINED TO S OF 25N. WITH THE WINDS ALREADY CUTTING OFF OVER THE NW GULF...SEAS HAVE BEGUN TO SUBSIDE TO 3 TO 5 FT EXCEPT 2 TO 3 FT ALONG THE IMMEDIATE COAST. IN THE SW WATERS W OF THE FRONT...NOAA WAVEWATCH GUIDANCE STILL SHOWS 5 TO 8 FT SEAS...THOUGH THERE ARE NO IN SITU OBSERVATIONS TO CORROBORATE THESE ESTIMATES. E OF THE FRONT...A MOSTLY GENTLE NE TO E WIND FLOW PREVAILS WITH SEAS 1 TO 2 FT OVER A LARGE PART OF THE EASTERN GULF OF MEXICO WHILE 2 TO 4 FT SEAS ARE NOTED CLOSER TO THE BOUNDARY OVER THE SW GULF. OVER THE NEXT 24 HOURS...MODELS SHOW THE FRONT OVER THE GULF BECOMING WEAKER AND DIFFUSE AT THE SAME TIME THE PERSISTENT NORTHERLY FLOW OF 15 TO 20 KT W OF IT BEGINS TO DIMINISH. STILL THOUGH...MODEL GUIDANCE PERSISTS WEAK LOW PRESSURE AND A TROUGH RUNNING NORTH-TO-SOUTH FROM THE LOW TO THE CENTRAL BAY OF CAMPECHE UNTIL SAT. SEAS OF 4 TO 7 FT W OF THE FRONT SHOULD SUBSIDE TO 3 TO 5 FT LATE FRI INTO SAT AND THEN 2 TO 3 FT LATER THIS WEEKEND. THE ONLY OTHER ITEM OF NOTE FOR MARINERS WILL BE THE STRENGTHENING OF SURFACE HIGH PRESSURE OVER THE EASTERN U.S. BEHIND A STATIONARY FRONT DRAPED NE TO SW OVER THE WESTERN ATLANTIC WATERS. ALTHOUGH THE PRIMARY EFFECTS OF THE STRONGER RIDGE WILL BE TO CREATE INCREASED WINDS OFFSHORE THE EAST COAST...MODELS DO SHOW SOME MARGINAL INCREASE IN WINDS N OF 28N OVER THE N CENTRAL AND NE GULF. THIS SHOULD RESULT IN SLIGHTLY HIGHER SEAS OVER THESE AREAS...WITH GUIDANCE SHOW SEAS OF 2 TO 4 FT WITH A FEW 5 FT REPORTS POSSIBLE. OTHERWISE...A GENERAL LIGHT NE TO E WIND AND 1 TO 3 FT SEAS SHOULD PREVAIL E OF 90W AND N TO NE WINDS AND 2 TO 4 FT SEAS SHOULD PREVAIL W OF 90W THROUGH THE WEEKEND. CARIBBEAN AND TROPICAL ATLC... A TROPICAL WAVE OVER THE WESTERN CARIBBEAN AND CENTRAL AMERICA YESTERDAY HAS SINCE MOVED INTO THE EASTERN PACIFIC. HOWEVER... ANOTHER ACTIVE TROPICAL WAVE IS BEING ANALYZED ALONG 83W AND IS MOVING W AT 10 TO 15 KT. AS A RESULT...UNSETTLED CONDITIONS IN THE FORM OF SCATTERED TO OCCASIONALLY NUMEROUS TSTMS EXTEND FROM THE SW CARIBBEAN INTO THE GULF OF HONDURAS. ENHANCED CONVECTIVE ACTIVITY SHOULD PERSIST UNTIL THE WAVE ADVANCES W OF THE AREA BY LATE THU. ELSEWHERE...A MORNING QUIKSCAT PASS INDICATED THE TYPICAL EASTERLY FLOW OF UP TO 20 KT FROM 11N TO 15N BETWEEN 70W AND 77W. SEAS OVER THIS AREA ARE ESTIMATED TO RANGE FROM 4 TO 7 FT EXCEPT 5 TO 8 FT CLOSER TO THE COLOMBIAN COAST. HOWEVER...MODELS SHOW THIS FLOW WEAKENING IN RESPONSE TO A WEAKER LARGE-SCALE PRESSURE GRADIENT BEGINNING THU AND EXTENDING INTO THE WEEKEND. OTHERWISE...LIGHT TO MODERATE TRADES ARE EXPECTED THROUGH THE PERIOD...GENERALLY NE TO E 10 TO 15 KT. SEAS SHOULD RANGE FROM 3 TO 5 FT IN THE E TO 2 TO 4 FT IN THE W. SW N ATLC... A WEAK LOW-LEVEL TROUGH EXTENDING FROM 31N65W TO 23N75W CONTINUES TO DRIFT WEST BUT SHOULD LOSE ITS IDENTITY WITHIN 24 HOURS. S TO SW WINDS TO 20 KT ARE OCCURRING E OF THIS FEATURE N OF 29N MAINLY E OF THE FORECAST AREA. HOWEVER...THERE COULD STILL BE SOME WINDS TO 20 KT OVER THE FAR NE WATERS LATER THIS AFTERNOON OR EVENING. OTHERWISE...A WEAK EARLY SEASON COLD FRONT HAS POKED INTO THE FAR NW WATERS EXTENDING FROM 31N79W TO 29N81W EARLY THIS AFTERNOON AND IS FORECAST TO CONTINUE EASTWARD TO A POSITION FROM 31N72W TO CENTRAL FLORIDA THU AFTERNOON...WHERE IT SHOULD BECOME ESSENTIALLY STATIONARY. STRONG HIGH PRESSURE BUILDING OVER THE CAROLINAS BEHIND THE FRONT IS EXPECTED TO STRENGTHEN THE LOW-LEVEL GRADIENT NEAR AND OFFSHORE THE U.S. EAST COAST... WHICH SHOULD LEAD TO BRISK NE WINDS ALONG THE SE U.S. COAST FRI AND SAT. SOME NE WINDS TO 20 KT ARE POSSIBLE NEAR THE NORTHERN BORDER OF THE NW WATERS DURING THIS TIME...BUT OF GREATER IMPORTANCE WILL BE THE ARRIVAL OF NE SWELL. SEAS OF 3 TO 5 FT N OF 28N W OF 75W LATE FRI SHOULD BUILD TO 5 TO 8 FT IN NE SWELL BY EARLY SAT AND THEN TO 6 TO 9 FT BY LATE SAT OR EARLY SUN. THE NE SWELL SHOULD EVENTUALLY FILL THE REMAINDER OF THE SW N ATLC WATERS THIS WEEKEND AND EARLY NEXT WEEK...WITH 5 TO 7 FT SEAS COVERING ALL AREAS E OF THE BAHAMAS BY MON. NE SWELL WILL ALSO BLEED THROUGH THE BAHAMAS AND REACH THE FLORIDA SE COAST AND CUBA...WITH NOAA WAVEWATCH III INDICATING 3 TO 5 FT SEAS LATER MON. MODELS SHOW THE STATIONARY FRONT SHIFTING NW AS A WARM FRONT SUN AND MON...WITH LOW PRESSURE POSSIBLY FORMING ALONG THE FRONT OFF THE SE U.S. COAST LATER MON OR TUE. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER KIMBERLAIN. TROPICAL PREDICTION CENTER.