000 AGXX40 KNHC 060540 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 140 AM EDT SUN JUL 6 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... LATEST SFC ANALYSIS ATLC SUBTROPICAL RIDGE EXTENDING ACROSS N CENTRAL FL THROUGH THE NRN GULF...WITH AN AXIS ROUGHLY ALONG 28N. CLOSE TO THE RIDGE AXIS...WINDS ARE TYPICALLY LIGHT... GENERALLY BLOWING E TO SE 10 KT OR LESS FROM 25N-28N AND SW TO W 10 KT OR LESS N OF THE RIDGE ALONG TO ALONG THE NRN GULF COAST. REPORTS FROM BUOYS AND C-MAN STATIONS INDICATE A WIDESPREAD AREA OF SEAS 2 FT OR LESS OVER THE NE QUARTER OF THE GULF...WHILE 3 TO 5 FT SEAS ARE MOST COMMON OVER THE NW WHERE THE E TO SE FLOW IS PILING UP THE WATER. S OF THE RIDGE AXIS...A TIGHTER PRES GRADIENT BETWEEN THE ATLC SUBTROPICAL RIDGE AND LOW PRES OVER MEXICO IS GENERATING A STEADY STREAM OF E TO SE 10 TO 15 KT WINDS BLOWING FROM THE STRAITS OF FLORIDA INTO THE W CENTRAL GULF...WITH SEAS OF 2 TO 4 FT E OF 90W AND 4 TO 6 FT W OF 90W. WHERE THE GRADIENT IS TIGHTEST OVER THE SW...E TO SE 15 TO 20 KT WINDS ARE OBSERVED. BUOY 42055...FOR EXAMPLE...NEAR 22N94W IS REPORTING NEARLY CONTINUOUS 20 KT WINDS WITH SEAS OF 4 TO 5 FT. ELSEWHERE OVER THE SW...SEAS ARE GENERALLY RUNNING BETWEEN 4 AND 7 FT. FROM TONIGHT THROUGH MID-WEEK NEXT WEEK...GLOBAL MODELS INDICATE LITTLE CHANGE TO THE ABOVE PATTERN EXCEPT THAT THE RIDGE AXIS SHOULD MIGRATE FROM AROUND 28N TONIGHT TO CLOSER TO 30N BY EARLY THIS COMING WEEK. THE ONLY OTHER NOTEWORTHY CHANGE WILL BE A SUBTLE INCREASE IN WINDS OVER THE SW AND W CENTRAL AREAS LATER TODAY INTO MON IN RESPONSE TO LOW PRES STRENGTHEN BRIEFLY OVER THE CENTRAL AND NRN PLAINS. GUIDANCE SHOWS A FAIRLY CONSTANT E TO SE FLOW OF 20 KT MOSTLY S OF 25N W OF 90W...WITH SOME HINT OF WINDS REACHING 25 KT. THE INCREASE IN WIND WILL BE FOLLOWED BY SEAS BUILDING TO 5 TO 8 FT IN SE WIND WAVES...WITH THE GFDL AND NOAA WAVEWATCH III MODELS SHOWING A PEAK OF 9 FT WITHIN ABOUT A 60 NM RADIUS OF 23N96W BEGINNING LATER THIS AFTERNOON THROUGH MON. THE SE SWELL SHOULD CAUSE AN INCREASE IN WAVE HEIGHTS SHOULD RESULT IN AN INCREASE IN WAVE HEIGHTS EVEN OVER THE NW...ESP IMMEDIATELY OFFSHORE THE S TX COAST BY MON. THE LOW-LEVEL FLOW SHOULD THEN RELAX TUE AFTERNOON BACK TO E TO SE 15 TO 20 KT...WHICH SHOULD CAUSE SEAS TO SUBSIDE TO THE 4 TO 7 FT RANGE OVER THE SW. OTHERWISE...FAVORABLE MARINE CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD EXCEPT FOR SCATTERED CONVECTION ERUPTING OVER NE MEXICO...S TX...AND ADJACENT AREAS OF THE GULF TODAY THANKS TO A MID- TO UPPER-LEVEL DISTURBANCE ACROSS THE REGION. LIKEWISE... MODEL GUIDANCE SHOW A SIMILAR DISTURBANCE ALOFT OVER THE ERN GULF MON INTO TUE...WHICH COULD ALSO ENHANCE SHOWER AND TSTM DEVELOPMENT E OF 88W DURING THIS TIME. CARIBBEAN... CURRENT SFC ANALYSIS SHOWS CONDITIONS TYPICAL CONDITIONS FOR THE FIRST WEEK OF JULY ACROSS THE CARIBBEAN BASIN. BUOY AND SHIP REPORTS AS WELL AS EVENING QUIKSCAT PASSES INDICATE MODERATE TO FRESH TRADES FROM 11N-17N E OF 78W...WHILE LIGHT TO MODERATE TRADES COVER THE REST OF THE CARIBBEAN. THE ONE EXCEPTION IS OVER THE GULF OF HONDURAS WHERE E TO SE 20 KT WINDS ARE SUSPECTED. AS OF 0600 UTC...SEAS RANGE FROM 4 TO 7 FT S OF 17N E OF 78W AND 3 TO 5 FT ELSEWHERE EXCEPT FOR THE GULF OF HONDURAS WHERE 5 TO 8 FT SEAS ARE ESTIMATED. MODELS SHOW A TROPICAL WAVE CURRENTLY ALONG 67W/68W TRACKING WESTWARD AT 10 TO 15 KT OVER THE CENTRAL CARIBBEAN TODAY...FOLLOWED BY A STRENGTHENING OF THE LOW-LEVEL ATLC RIDGE. IN TURN...THIS SHOULD LEAD TO AN INCREASE IN WINDS AND SEAS ACROSS THE EASTERN AND CENTRAL CARIBBEAN LATER TODAY AND MON...WITH THE EASTERLY SWELL PROPAGATING DOWNSTREAM INTO THE WESTERN CARIBBEAN TUE AND WED. AT THEIR PEAK TUE MORNING AND AFTERNOON...NOAA WAVEWATCH III OUTPUT SHOWS A LARGE AREA OF 8 TO 12 FT SEAS COVERING THE AREA FROM 11N-17N BETWEEN 70W AND 83W. EXPECT WINDS TO ABATE AND SEAS TO SUBSIDE AS SOON AS LATE TUE...WITH ALL AREAS EXCEPT THE WESTERN CARIBBEAN TO SEE A REDUCTION IN SEAS BY WED AFTERNOON. OTHERWISE...TROPICAL STORM BERTHA SHOULD PASS A FEW HUNDRED MILES NE OF THE LESSER ANTILLES AND PUERTO RICO TUE AND WED. S OF THE STORM TRACK OVER THE EASTERN CARIBBEAN...A WEAK PRES PATTERN SHOULD TEMPORARILY RESULT IN LIGHTER TRADES. HOWEVER ...LONG PERIOD NE SWELL OUTRUNNING THE STORM IS EXPECTED TO ARRIVE OVER LESSER ANTILLES AND PUERTO RICO TUE AND WED AND SUBSIDE GOING INTO THU. GIVEN THE CURRENT FCST...PEAK SEAS OF 6 TO 9 FT IN THE NE ATLC PASSAGES ARE EXPECTED LATE TUE INTO WED. SW ATLC... A STAGNANT PATTERN OF LOW-LEVEL SUBTROPICAL RIDGING ARCING WSW FROM 30N69W TO 28N80W REMAINS IN PLACE OVER THE SW ATLC EARLY THIS MORNING. CLOSE TO THE RIDGE AXIS...WINDS ARE RELATIVELY LIGHT...BLOWING MOSTLY SE TO S 10 TO 15 KT N OF 25N EXCEPT FOR S TO SW WINDS OBSERVED NEAR THE IMMEDIATE NE FLORIDA COAST WITH SPEEDS AVERAGING CLOSE TO 15 KT. SEAS AVERAGE 3 TO 5 FT OVER MOST OF THIS AREA...WITH THE HIGHEST SEAS TO THE SE. HOWEVER ...NEAR THE FLORIDA E COAST SEAS ARE RUNNING AROUND 2 FT OR LESS. S OF 25N...A STEADY STREAM OF E TO SE 15 TO 20 KT WINDS PERSIST...WITH THE STRONGEST GENERALLY S OF 22-23N. SEAS AVERAGE 5 TO 7 FT E OF THE BAHAMAS AND 3 TO 5 FT W OF THE BAHAMAS...AWAY FROM THE FL COAST. IN THE SHORT-TERM...LITTLE CHANGE IS EXPECTED OVER THE NRN WATERS. TO THE SOUTH THOUGH...THE NRN END OF THE TROPICAL WAVE NOW TRACKING ALONG 67W/68W IS LIKELY TO AFFECT MARINE CONDITIONS S OF 23-24N BEGINNING TODAY THROUGH EARLY TUE. THOUGH THERE IS NO SIGNIFICANT CONVECTION ASSOCIATED WITH THIS FEATURE...MODELS DO SHOW A STRENGTHENING OF THE ATLC SUBTROPICAL RIDGE BEHIND IT AND A SURGE OF EASTERLY FLOW. THE FETCH AND DURATION OF THE WINDS...HOWEVER...SHOULD NOT BE LONG ENOUGH TO AFFECT WAVE HEIGHTS APPRECIABLY. OF CRITICAL IMPORTANCE THOUGH IS THE TRACK OF TROPICAL STORM BERTHA...CURRENTLY CENTERED WELL E OF THE FCST AREA. THE NHC FCST HAS BERTHA MOVING ON A WNW TO NW TRACK N OF THE CARIBBEAN ISLANDS TOWARD THE WESTERN ATLC EARLY THIS WEEK. AHEAD OF THE STORM...WINDS SHOULD BACK NE EAST OF 70W AND LONG PERIOD NE SWELL OUTRUNNING THE STORM ARRIVING OVER THE FAR E PART OF THE AREA WED. BY THU...HURRICANE CONDITIONS ARE POSSIBLE OVER SOME PORTION OF THE EASTERN SW ATLC ZONE ON THE CURRENT FCST TRACK. USERS ARE REMINDED THAT TYPICAL ERRORS ON DAY 4 AND DAY 5 FCSTS ARE SEVERAL HUNDRED MILES...AND UNCERTAINTY IN THE CURRENT TRACK IS LIKELY GREATER-THAN-NORMAL PER THE LATEST DISCUSSION. PLEASE CONTINUE TO CONSULT LATEST NHC PRODUCTS FOR UP-TO-THE-DATE INFORMATION ON BERTHA. TRCPL N ATLC... LATEST NHC FCST TRACKS BERTHA THROUGH THE NE WATERS TUE AND WED WITH TROPICAL STORM AND POSSIBLY HURRICANE CONDITIONS OVER THIS AREA. AS SOON AS LATE TODAY THOUGH...WINDS SHOULD BACK MORE NE OVER THE NORTHERN WATERS AND GRADUALLY INCREASE FROM E TO W. LONG PERIOD NE SWELL RUNNING AWAY FROM THE STORM SHOULD ALSO BEGIN ARRIVING...WITH CONDITIONS FURTHER DETERIORATING MON...MOSTLY N OF 18N. FARTHER S...A WEAK PRES PATTERN SHOULD RESULT IN LIGHT WINDS MOSTLY FROM THE NE TO E...EXCEPT SE TO S IMMEDIATELY E OF THE STORM. LONG PERIOD NE SWELL SHOULD ALSO BEGIN ARRIVING...RESULTING IN SOME INCREASE IN WAVE HEIGHTS. WINDS AND SEAS SHOULD DECREASE AREA WIDE THU. AS ALWAYS...PLEASE CONTINUE TO REFER TO LATEST NHC PRODUCTS REGARDING BERTHA FOR UPDATED FORECASTS. ATLANTIC... .NONE. AMZ087...HRCN CONDS EXPCTD N OF 19N E OF 64W EARLY TUE-EARLY WED. AMZ080...HRCN CONDS EXPCTD 22N-28N E OF 70W WED NIGHT AND THU. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. .FORECASTER KIMBERLAIN. TROPICAL PREDICTION CENTER.