000 AGXX40 KNHC 151824 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT FRI AUG 15 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... SHORT-TERM... LATEST SFC ANALYSIS REVEALS A RIDGE AXIS EXTENDING FROM AROUND 26N82W SW INTO THE SW GULF OF MEXICO...WITH LIGHT/MODERATE S TO SW FLOW N OF THE RIDGE AXIS /EXCEPT W NEAR THE N GULF COAST/ AND A GENERAL E TO SE FLOW S OF THE AXIS. ONLY WIND SPEEDS AT OR NEAR 20 KT FROM ABOUT 20N TO 25N BETWEEN 88W AND 94W...AS INDICATED BY MORNING QSCAT DATA. BUOY AND SHIP REPORTS N OF THE RIDGE AXIS CONFIRM MOSTLY 3 TO 4 FT SEAS...WITH 3 TO 5 FT SEAS OVER THE SW WATERS...AND 2 FT OR LESS WAVE HEIGHTS CLOSER TO THE RIDGE AXIS OVER THE FLORIDA STRAITS AND SE GULF. LATE SAT GFS MODEL GUIDANCE HAS BEEN RATHER INSISTENT UPON FORMING WEAK BUT BROAD SFC LOW PRES ALONG THE N CENTRAL AND NE GULF IN RESPONSE TO SHORTWAVE ENERGY ENTERING THE BASE OF THE ERN CONUS TROF. THE GFS THEN EITHER KEEPS LOW PRES IN PLACE OR TRACKS IT SLOWLY EASTWARD SUN INTO MON UNTIL DISSIPATION. THE ECMWF ALSO CARRIED A FAINT HINT OF THIS FEATURE...BUT IT APPEARED TO BE FAR MORE INSIGNIFICANT THAN IN THE GFS FIELDS. WITH LITTLE SUPPORT FROM THE OTHER GLOBAL MODELS...THIS FCST WILL DOWNPLAY THE EXISTENCE OF THIS FEATURE. LONGER-TERM... OTHERWISE...THE LOW-LEVEL RIDGE AXIS SHOULD LIFT N OVER THE WEEKEND AND EXTEND FROM THE NE TO SW GULF WATERS BY MON. ALL EYES ARE ON THE STRONG TROPICAL WAVE ALONG 69W AND ITS ASSOCIATED SFC LOW NOW OVER THE ERN TIP OF THE DOMINICAN REPUBLIC...WHICH COULD DEVELOP INTO A TROPICAL DEPRESSION LATER TODAY OR THIS WEEKEND. ALTHOUGH PREVIOUS MODELS RUNS HAVE KEPT THIS SYSTEM N OF THE GREATER ANTILLES WITH A NW BEND TOWARD THE E COAST OF FLORIDA EARLY NEXT WEEK...THE 12Z GFS AND GFDL SOLUTIONS CARRY THE SYSTEM INTO THE ERN GULF OF MEXICO BY MON. WITH SOME OF THE 12Z YET TO ARRIVE...WILL MAKE NO CHANGES TO THE LONGER-RANGE FCST OVER THE ERN GULF ZONE UNTIL MODELS COME INTO BETTER AGREEMENT ON THIS SCENARIO. IN THE VERY LEAST...MODELS SHOW A LARGE CYCLONIC ENVELOPE NEAR OR E OF FLORIDA EARLY NEXT WEEK...WHICH SHOULD FAVOR A LIGHT TO MODERATE N TO NE FLOW OVER EASTERN GULF WATERS AND WAVE HEIGHTS OF 1 TO 3 FT. CARIBBEAN AND TROPICAL N ATLC... SHORT-TERM...A BROAD 1009 MB SFC LOW...ASSOCIATED WITH A STRONG TROPICAL WAVE...IS LOCATED OVER THE EASTERN TIP OF HISPANIOLA EARLY THIS AFTERNOON...MOVING W TO WNW AROUND 10 KT. THE EASTERN EDGE OF A 0954 UTC QSCAT PASS REVEALED SW TO W 20 TO 30 KT WINDS WITHIN ABOUT 120 NM OF THE S SEMICIRCLE OF THE LOW...AND SATELLITE IMAGERY INDICATED A WIDESPREAD TSTMS AND SQUALLS COVERING THE AREA N OF 16N BETWEEN PUERTO RICO AND HISPANIOLA. ALTHOUGH THERE ARE NO AVAILABLE DATA...WAVE HEIGHTS ARE ESTIMATED TO BE 4 TO 7 FT WITHIN ABOUT 200 NM S OF THE LOW...WITH THE HIGHER VALUES LIKELY FARTHER N WHERE THE WIND HAS BEEN BLOWING LONGER. ELSEWHERE...QSCAT DATA AS WELL AS BUOY AND SHIP REPORTS INDICATE LIGHT/MODERATE NE FLOW AHEAD OF THE WAVE AXIS AND E TO SE FLOW IN ITS WAKE. MEAN WAVE HEIGHTS RANGE FROM 2 TO 4 FT E OF 75W. SIMILAR CONDITIONS PREVAIL OVER THE W CARIBBEAN EXCEPT IN A NARROW ZONE S OF 19N W OF 86W...WHERE QSCAT DATA YESTERDAY AND NOW AGAIN TODAY INDICATED E TO SE WINDS TO 20 KT. LONGER-TERM...WITH RESPECT TO BROAD LOW PRES NOW OVER THE ERN DOMINICAN REPUBLIC...12Z MODELS HAVE TRENDED MUCH FARTHER LEFT OF EARLIER GUIDANCE. SHOULD THIS TREND CONTINUE...FUTURE OFFSHORES FCST PACKAGES WILL BEGIN TO SHOW MORE OF AN IMPACT OVER THE CARIBBEAN WATERS DOWNSTREAM OF HISPANIOLA AND S OF CUBA. FOR THE TIME BEING...20 TO 30 KT NE FLOW BLOWING THROUGH THE WINDWARD PASSAGE SHOULD SHIFT SW TO W AFTER SFC LOW PRES PASSES SAT AFTERNOON THROUGH EARLY SUN. ALTHOUGH THE FETCH AREA SHOULD BE SMALL AND THE DURATION OF STRONGEST WINDS NO MORE THAN 24 HOURS...WAVE HEIGHTS SHOULD BUILD UP TO 5 TO 8 FT IN THE WINDWARD PASSAGE AND ADJACENT CARIBBEAN WATERS. S TO SW FLOW BETWEEN JAMAICA AND CUBA SHOULD BEGIN TO DIMINISH SUN INTO MON. ELSEWHERE...BROAD SFC LOW PRES NEAR 15N50W IS ASSOCIATED WITH ANOTHER STRONG TROPICAL WAVE MOVING WNW TO NW AT 10 TO 15 KT. GLOBAL MODELS AGREE ON TAKING THIS SYSTEM OVER THE NE WATERS SUN INTO EARLY MON...WITH NE TO E 20 KT WINDS ARRIVING OVER THE AREA AS SOON AS LATE SAT AND SHIFTING E TO SE SUN AFTER ITS PASSAGE. GUIDANCE THEN TRACKS THE WEAKENING SYSTEM NW AND OUT OF THE NRN PART OF THE TROPICAL N ATLC LATE SUN INTO MON. OF FINAL NOTE...SEVERAL GLOBAL MODELS INCLUDING THE GFS CARRY BROAD SFC LOW PRES ASSOCIATED WITH YET ANOTHER VIGOROUS TROPICAL WAVE INTO THE TROPICAL N ATLC WATERS WED. AT THE MOMENT...WILL INDICATE SOME MINOR INCREASE IN WINDS AND SEAS LAST PERIOD BUT WILL AWAIT FUTURE GUIDANCE BEFORE DEVELOPING THIS FURTHER. SW N ATLC... SHORT-TERM...LOW PRES MOVING AWAY FROM THE CAROLINAS HAS LEFT BEHIND A TRAIL OF SW 15 TO 20 KT WINDS MOSTLY N OF THE AREA ...BUT WINDS HAVE DIMINISHED TO 10 TO 15 KT OVER THE NW WATERS AS OF THIS MORNING. SFC RIDGE AXIS LYING FROM 30N65W TO S FLORIDA SHOULD LIFT N TONIGHT AND SAT...REACHING A POSITION FROM 31N65W TO CENTRAL FLORIDA LATER THIS WEEKEND BEFORE SHIFTING E OF THE AREA MON. N OF THE RIDGE AXIS...S TO SW WINDS OF 10 TO 15 KT SHOULD BE THE RULE WITH SEAS SUBSIDING TO 3 TO 5 FT OFFSHORE AND 1 TO 3 FT NEAR THE FLORIDA COAST. S OF THE RIDGE AXIS...NE 10 TO 15 KT WINDS ARE EXPECTED OUTSIDE OF DEVELOPING LOW PRES TO THE S...WITH WAVE HEIGHTS OF 4 TO 6 FT E OF THE BAHAMAS AND 1 TO 3 FT W OF THE BAHAMAS. AS WITH THE OTHER ZONES...THE MAIN MARINE FEATURE THIS PERIOD WILL BE BROAD SFC LOW PRES NOW OVER EASTERN HISPANIOLA...WHICH IS FCST TO MOVE W TO WNW AT 10 KT AND POSSIBLY DEVELOP INTO A TROPICAL CYCLONE. MODELS HAVE TRENDED DRAMATICALLY W THIS MORNING...TAKING LOW PRES NOW S OF THE GREATER ANTILLES AND NW THROUGH THE STRAITS OF FLORIDA INTO THE SE GULF. GIVEN THE SUDDEN SHIFT IN THE GUIDANCE...CONFIDENCE IN ANY PARTICULAR TRACK IS FAIRLY LOW BEYOND ABOUT 48 HOURS...THOUGH WHAT SEEMS CLEAR IS THAT BROAD SFC LOW PRES OF SOME FORM SHOULD AFFECT THE SW PART OF THE ZONE SUN THROUGH TUE. FOR THE TIME BEING...THE FCST WILL CONTINUE TO INDICATE WINDS OF 20 TO 30 KT AND A POSSIBLE TROPICAL CYCLONE OVER THE SOUTHERN OR SW WATERS OVER THE WEEKEND AND INTO EARLY NEXT WEEK UNTIL GUIDANCE BECOMES MORE DEFINITIVE. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. .FORECASTER KIMBERLAIN. TROPICAL PREDICTION CENTER.