000 AGXX40 KNHC 170748 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 348 AM EDT TUE AUG 17 2010 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... STLT AND RADAR IMAGES THIS MORNING SUGGEST THAT THE LOW PRES AREA ACROSS THE N CENTRAL GULF REMAINS ELONGATED NE TO SW. A MID LEVEL PORTION OF THE CIRCULATION HAS BECOME SHEARED TO THE SE AND JUST OFF OF THE S CENTRAL COAST OF LOUISIANA...WITH A LLCC ELONGATED FROM JUST E OF THE MOUTH OF THE MISSISSIPPI NE TO MOBILE BAY. CNVTN HAS INTENSIFIED ALONG THE ERN SHORELINE OF SE LOUISIANA AND THIS TREND MAY CONTINUE FOR THE NEXT SEVERAL HOURS. SW TO S FLOW IN THE ERN SEMICIRCLE OF THE LLCC HAS BEGUN TO FINALLY YIELD 20 KT WINDS PER RECENT OBS FROM BUOY 42012 WITH SEAS 4-5 FT IN THIS AREA. THIS LLCC IS EXPECTED TO MOVE W TO W-NW NEXT 6-8 HOURS AND INLAND ACROSS SE COASTAL LOUISIANA... LAKE PONTCHARTRAIN...AND SRN MS...WHERE MODELS SUGGEST SOME FURTHER IMPROVEMENT IN THE LLVL CIRCULATION IS POSSIBLE. THIS MAY CONTINUE TO PRODUCE SLY WINDS AROUND 20 KT ACROSS THE COASTAL ZONES OF SE AND S CENTRAL LA...SRN MS AND AL THROUGHOUT TODAY...WITH SEAS BUILDING 4-6 FT. BANDS AND LINES OF STRONG CNVTN ARE ALSO LIKELY TO PERSIST ACROSS THE INNER AND OUTER COASTAL WATERS OF S LA AND SE TEXAS AS WELL. THE LOW IS FORECAST TO SHIFT NW INTO CENTRAL LA TONIGHT AND WED AND ALLOW A MODERATE SLY RETURN FLOW TO DOMINATE THE BASIN THROUGH WED MORNING BEFORE WEAK RIDGING EXTENDS W ALONG 26N WED NIGHT AND LIFTS N TO 27N ON THU. THIS PERSISTENT RIDGING WILL CONTINUE THROUGH THE END OF THE WEEK AND MAY LEAD TO 15-20 KT SELY FLOW ACROSS SW AND W PORTIONS OF THE BASIN FRI AND SAT. SW N ATLC... WEAK FRONTAL BOUNDARY SNAKING WSW TO ENE ACROSS FAR NW PORTIONS HAS BEGUN TO DRIFT N PAST 12 HOURS AS HIGH PRES BUILDS WEAKLY W ALONG 25N E OF THE BAHAMAS. THIS RIDGING BEING AIDED BY THE TROPICAL WAVE MOVING ACROSS THE E CARIBBEAN AND AN ASSOCIATED MID LEVEL PERTURBATION AND WIND SURGE JUST BEHIND IT. THIS TANDEM OF FEATURES IS USHERING IN A ZONE OF 15-20 KT ELY WINDS NOW ENTERING EXTREME SE PORTIONS THAT WILL SHIFT W-NW OVER THE NEXT FEW DAYS...AND MOVE THROUGH THE SRN BAHAMAS AND THE GREATER ANTILLES...AND REACH THE FLORIDA STRAITS BY 06Z THU. INTERACTION OF WITH THIS MID LEVEL PERTURBATION AND A ZONE OF SAL TO THE N AND ALONG THE LEADING EDGE OF THE TROPICAL WAVE WILL ALLOW FOR THE DEVELOPMENT OF SCATTERED SQUALLS AND TSTMS TO RACE WNW NEAR 20 KT ACROSS THIS AREA...AND THE POTENTIAL FOR GALE FORCE WINDS GUSTS. AS STATED EARLIER...THIS WIND SURGE WILL AID IN WWD RIDGING OF THE ATLC HIGH...WHICH WILL ALLOW E TO SE TRADES TO BUILD ACROSS ALL WATERS S OF 25N AND WEAKLY INTO EXTREME S FL BY THU...WITH SEAS BUILDING 5-6 FT IN E WIND SWELL S OF 23N. SMALL TO MODERATE NELY SWELL AROUND 11 SEC LOOKS TO HAVE PEAKED YDA MORNING ACROSS MUCH OF THE AREA AND CONTINUES TO SLOWLY FADE ATTM. CARIBBEAN SEA AND TROPICAL N ATLC... A TROPICAL WAVE HAS MOVED ACROSS NICARAGUA AND HONDURAS DURING THE PAST 12 HOURS...WITH SCATTERED CNVTN BEHIND IT BEING TRANSPORTED NW ACROSS THE CARIB W OF 80W THIS MORNING. THE OTHER TROPICAL WAVE IN THE E CARIB HAS MOVED INTO FAR ERN HISPANIOLA TO THE A-B-C ISLANDS...WITH THE MID LEVEL PERTURBATION MOVING ACROSS PUERTO RICO AND THE NE CARIB ATTM. OBSERVATIONS EARLIER TONIGHT INDICATED SEVERAL REPORTS OF WIND GUSTS 24-30 PLUS KT ACROSS THE VIRGIN ISLANDS...OCCURRING IN SQUALLS AND TSTMS MOVING THROUGH THE AREA. A BROADER WIND SURGE OF AROUND 20 KT WILL MOVE W AND W-NW ACROSS THE CARIB NEXT 48 HOURS AND SIGNIFICANTLY KICK UP SEAS N OF 15N TO 6-8 FT IN ELY WIND SWELL...HIGHEST S OF HISPANIOLA AND THE BARAHONA PENINSULA. THE WIND SURGE WILL SHIFT WNW INTO THE NW CARIB THU AFTERNOON AND NIGHT AND INTO THE YUCATAN BY FRI AFTERNOON...WITH WINDS AND SEAS GRADUALLY DIMINISHING ACROSS THE BASIN BEHIND IT. SOME COMPUTER MODEL GUIDANCE CONTINUES TO SHOW POTENTIAL FOR A TROPICAL WAVE TO BECOME WELL ORGANIZED ACROSS E CENTRAL ATLC BY THE END OF THE WEEK...AND IS IN LINE WITH CLIMATOLOGY. WARNINGS... SW N ATLC... .NONE. CARIBBEAN... .NONE. .GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING