000 AGXX40 KNHC 231801 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT THU OCT 23 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO... CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... AN UNUSUALLY STRONG CUT-OFF LOW SITTING OVER THE PLAINS EARLY THIS AFTERNOON HAS INTRODUCED A COLD FRONT OVER THE WESTERN GULF...EXTENDING FROM SE LOUISIANA TO THE CENTRAL BAY OF CAMPECHE. AN 1146 UTC QUIKSCAT PASS SHOWED N 20 TO 30 KT WINDS N OF 25N W OF THE FRONT THIS MORNING...WHILE SHIPS AND NEARBY BUOYS INDICATED SEAS OF 6 TO 10 FT. INDICATIONS ARE THAT SIMILAR WINDS HAVE SINCE ARRIVED S OF 25N W OF THE FRONT...THOUGH SEAS HAVE NOT YET RESPONDED. AHEAD OF THE FRONT SATELLITE PICTURES AND THE SAME EARLIER QUIKSCAT PASS SHOWED BROAD BUT WEAK SURFACE LOW PRES FORMING OVER THE GULF NEAR 25N90W...MOVING N TO NE 10 KT. CYCLONIC WINDS AROUND THE LOW OF 10 TO 15 KT PREVAIL ALONG WITH SEAS OF 3 TO 5 FT. ELSEWHERE...AS LARGE-SCALE DIVERGENCE AND LIFT INCREASES AHEAD OF THE MID- TO UPPER-LEVEL TROUGH APPROACHING FROM THE W...MODELS AND SURFACE OBSERVATIONS SHOW A DEVELOPING WARM FRONT EXTENDING FROM THE LOW INTO THE SE GULF OF MEXICO. OVERRUNNING MOISTURE IS CREATING WIDESPREAD CLOUDINESS WITH SCATTERED SHOWERS AND TSTMS OVER THE EASTERN AND FAR NORTHERN GULF. IN ADDITION...A STRONG PRESSURE GRADIENT BETWEEN THE INCIPIENT LOW AND STRONG HIGH PRES RESTING OVER THE CAROLINAS IS PRODUCING E TO SE 20 TO 30 KT NE OF THE WARM FRONT WITH SEAS OF 7 TO 11 FT LIKELY FURTHER INCREASING TO 8 TO 13 FT THIS AFTERNOON AND TONIGHT. IN FACT...BUOY 42039 NEAR 28.8N86W IS CURRENTLY REPORTING E WINDS OF 30 KT WITH 11 FT SEAS. GOING FORWARD...LOW PRES OVER THE CENTRAL GULF SHOULD ACCELERATE NE AND FURTHER EVOLVE HEADING INLAND OVER THE FLORIDA PANHANDLE /FLORIDA BIG BEND LATE FRI MORNING OR AFTERNOON. AHEAD OF IT AND THE WARM FRONT LIFTING NE...CONTINUED STRONG E TO SE WINDS OF 20 TO 30 KT WILL CONTINUE WITH SEAS OF 8 TO 13 FT IN SCATTERED TO LOCALLY NUMEROUS SHOWERS AND TSTMS. THE TRAILING COLD FRONT SHOULD ADVANCE ACROSS MUCH OF THE REST OF THE GULF BY LATE FRI... WITH ONCE STRONG NW TO N WINDS DROPPING OFF TO 10 TO 15 KT. SEAS SHOULD SUBSIDE TO 4 TO 7 FT EXCEPT OVER THE NE WATERS WHERE SOME 8 OR 9 FT SEAS COULD STILL EXIST. MODELS SHOW THE FRONT STALLING VERY NEAR BUT LIKELY JUST N OF THE YUCATAN CHANNEL BY EARLY SAT AS HIGH PRES BUILDS INTO THE NORTHERN GULF BEHIND IT. THE STRENGTHENING GRADIENT SHOULD FAVOR N TO NE WINDS OF 20 KT OVER THE SOUTHERN WATERS WITHIN ABOUT 300 NM NW OF THE FRONT..WHICH SHOULD KEEP SEAS OF 4 TO 7 OR 5 TO 8 FT IN PLACE THROUGH THE WEEKEND. LONGER-TERM...ALL MODELS DEVELOP A PARTICULARLY SHARP AND UNUSUALLY AMPLIFIED BUT PROGRESSIVE TROUGH OVER THE EASTERN THIRD OF THE COUNTRY EARLY NEXT WEEK. IN RESPONSE TO THIS...A VERY STRONG FRONT SURGES SOUTHWARD FROM THE CENTRAL STATES AND ENTERS THE NORTHERN GULF WATERS MON MORNING AND MAKES IT THROUGH NEARLY THE REST OF THE GULF BY MON NIGHT. AS STRONG HIGH PRES BUILDS W OF THE FRONT LATER MON INTO TUE...MODELS SHOW NW TO N 20 TO 30 KT FLOODING THE GULF WHICH SHOULD BECOME MORE N TO NE TUE AND GRADUALLY DIMINISH FROM NW TO SE. AS A RESULT OF THE STRONG FORCING ON THE OCEAN SURFACE...SEAS BUILD TO 10 TO 15 FT OVER A LARGE AREA OVER THE NORTHERN GULF LATE MON AND SINK WELL SE INTO THE SOUTHERN GULF WATERS BY LATE TUE. ALTHOUGH NOT ENTIRELY APPARENT IN THE GUIDANCE YET...THE EXTREME NATURE OF THIS EVENT SUGGESTS THAT NEAR GALE FORCE WINDS ARE POSSIBLE OVER AT LEAST A PORTION OF THE GULF MON INTO TUE. MARINE INTERESTS IN THE GULF EARLY NEXT WEEK ARE ADVISED TO CONTINUE MONITORING FORECASTS FOR THE LATEST INFORMATION. CARIBBEAN AND TROPICAL N ATLC... BROAD BUT DISORGANIZED LOW PRES LIFTING N FROM THE YUCATAN HAS LEFT BEHIND WEAK LOW PRES OVER THE WEAK YUCATAN WHICH IS STARTING TO BECOME INDISCERNIBLE FROM AN ACTIVE TROPICAL WAVE MOVING IN FROM THE E. SATELLITE PICTURES SHOW A LARGE MASS OF CONVECTION OVER THE NW CARIBBEAN...MOSTLY W OF 80W...WHICH IS GRADUALLY MOVE W TO NW. A MORNING QUIKSCAT PASS INDICATED NE TO E WINDS OF 20 KT N OF 17N BETWEEN 80W AND 85W...WHICH HAPPENED TO BE OVER GUIDANCE VALUES. MUCH OF THIS WEATHER SHOULD LIFT N AND THEN NE AHEAD OF A FRONT PASSING THROUGH THE GULF TODAY AND TOMORROW. UNTIL THEN...EXPECT UNSETTLED CONDITIONS WITH E TO SE WINDS TO 20 KT OVER THE AREA N OF 15N W OF 80W. AS MENTIONED ABOVE...THE FRONT OVER THE GULF SHOULD STALL OUT JUST N OF THE YUCATAN CHANNEL SAT AND LIMP FORWARD SUN MORNING AND AFTERNOON. AS THIS OCCURS...NE WINDS OF 15 TO 20 KT SHOULD DEVELOP OVER THE FAR NW CARIBBEAN AND YUCATAN CHANNEL LATE SUN...WITH SEAS BUILDING TO 5 TO 8 FT IN N TO NE SWELL. A SECOND ...STRONGER FRONT IS FORECAST TO DESCEND THROUGH THE GULF MON... WITH VERY STRONG N TO NE WINDS OF 20 TO 30 KT RACING INTO THE FAR NW CARIBBEAN LATE MON AND DROPPING FARTHER SE TUE. EXPECT SEAS TO RAPIDLY BUILD TO 6 TO 10 FT LATE MON AND THEN 8 TO POSSIBLY 14 FT W OF 82 AND W OF THE FRONT BY LATE TUE...WITH HIGHEST SEAS IN THE YUCATAN CHANNEL. UNTIL THEN...MODERATE TO STRONG TRADES BLOWING FROM 12N TO 18N BETWEEN 67W AND 80W SHOULD CONTINUE AT LEAST FOR ANOTHER DAY BEFORE RELAXING OVER MUCH OF THE CARIBBEAN OVER THE WEEKEND AND EARLY NEXT WEEK. IN FACT...NE WINDS OF 10 KT OR LESS ARE EXPECTED OVER THE NW CARIBBEAN AHEAD OF THE AFOREMENTIONED COLD FRONT LATE IN THE WEEKEND WHILE NE TO E 10 TO 15 KT PREVAIL ELSEWHERE EXCEPT TO 20 KT OFF THE COAST OF COLOMBIA. THE LAST BIG STORY WILL BE THE SIGNIFICANT N TO NE SWELL PROPAGATING OUT OF THE WESTERN ATLC WHICH SHOULD REACH THE NE CARIBBEAN AND TROPICAL N ATLC WATERS LATER ON SUN AND MON. NOAA WAVEWATCH SHOULD SEAS BUILDING TO 8 TO 9 FT N OF THE NE CARIBBEAN ISLANDS...WITH SOME OF THE SWELL LIKELY BLEEDING THROUGH THE ADJACENT ATLC PASSAGES. THE SWELL SHOULD CONTINUE S AND E BOUND AND GRADUALLY DIE OFF GOING INTO TUE. SW N ATLC... LATEST SURFACE ANALYSIS DEPICTS A RATHER STRONG SURFACE RIDGE EXTENDING FROM THE CAROLINAS SOUTHWARD INTO THE FORECAST AREA. PRESSURE GRADIENT ANALYZED IS 1 MB/50 NM OFF E FLORIDA COAST EARLY THIS AFTERNOON...WHICH IS HELPING TO PRODUCE NE TO E WINDS OF 20 TO NEAR 30 KT GENERALLY N OF 24N W OF 72W. WAVE HEIGHTS ARE COMING IN ABOVE GUIDANCE...HOWEVER...WITH 6 TO 10 FT SEAS ENGULFING THE AREA N AND E OF THE BAHAMAS WHILE 2 TO 4 FT SEAS PREVAIL W OF THE BAHAMAS EXCEPT OFF THE SE FLORIDA COAST. NE TO E WINDS OF 15 TO 20 KT COVER THE REST OF THE AREA...WITH 6 TO 8 FT SEAS IN EVEN OLDER...LONG PERIOD N TO NE SWELL E OF THE BAHAMAS AND 3 TO 5 FT SEAS W OF THE BAHAMAS. THE STRONG SURFACE RIDGE OVER THE CAROLINAS SHOULD BEGIN SHIFTING E OVER THE NEXT 24 HOURS...AS LOW PRES PUSHES NE OUT OF THE GULF AND INTO THE SE CONUS. AS THE LOW GATHERS SOME STRENGTH AND ORGANIZATION...GUIDANCE SHOWS WINDS VEERING E TO SE OVER W OF 73W AT 20 TO 30 KT. FOR SEVERAL RUNS NOW THE GFS HAS INDICATED GALE FORCE SOUTHEASTERLY WINDS NE OF THE WARM FRONT VERY CLOSE TO THE NORTHERN BORDER FRI EVENING AND EARLY FRI NIGHT. EVEN THE ECMWF HAS 25-30 KT WINDS OVER THIS SAME AREA. ALTHOUGH THE GFS ENSEMBLE DATA IS MORE AMBIGUOUS...AM INCLINED TO INTRODUCE EXPECTED GALE CONDITIONS LATE FRI N OF 30N FROM 74W TO 78W. IN ADDITION TO THE VERY STRONG WINDS...MARINERS ARE ALSO LIKELY TO ENCOUNTER SCATTERED TO NUMEROUS SHOWERS AND TSTMS NEAR AND AHEAD OF THE WARM AND SURFACE LOW...WHICH COULD PRODUCE LOCALLY HIGHER WINDS AND SEAS. WITH THE MID- TO UPPER-LEVEL FLOW BACKING SAT AND SUN...THE FRONT SHOULD BEGIN TO SLOW. HOWEVER...STRONG E TO SE WINDS SHOULD CONTINUE GENERALLY N OF 24N E OF THE FRONT...WITH THE STRONGEST WINDS...SE TO S 20 TO 25 KT...LIKELY WITHIN 240 NM E OF THE FRONT N OF 29N. EXCEPT AHEAD OF THE FRONT N OF 28N OR 29N...WINDS SHOULD FURTHER DECREASE SUN BUT LONG PERIOD NE TO E SWELL SHOULD DOMINATE ALL AREAS N AND E OF THE BAHAMAS...WITH 8 TO 10 FT SEAS PERSISTING E OF 75W INTO SUN AFTERNOON. LONGER-TERM...A VERY STRONG COLD FRONT SHOULD BARREL OFF THE NE FLORIDA AND GEORGIA MON NIGHT AND CATCH UP WITH THE FIRST...WITH THE CONSOLIDATED TROUGH FINALLY MAKING HEADWAY E. IN THE WAKE OF THE FRONT...NW TO N WINDS OF 20 TO 30 KT SHOULD OVERSPREAD THE SW N ATLC WATERS...WITH 10 TO 15 FT SEAS DEVELOPING N OF THE BAHAMAS AND SPREADING SE. THE SWELL SHOULD EVEN BLEED THROUGH THE BAHAMAS WITH 6 TO 9 FT SEAS LIKELY EVEN THROUGH THE ATLC PASSAGES. ATLANTIC... GALE WARNING...AMZ080...N OF 30N BETWEEN 75W AND 79W FRI EVENING AND NIGHT. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER KIMBERLAIN. TROPICAL PREDICTION CENTER.