000 AGXX40 KNHC 221800 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT WED SEP 22 2010 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THERE ARE NUMEROUS OBSERVATIONS TO E TO SE WINDS TO 20 KT ACROSS THE EASTERN AND MIDDLE GULF TODAY. THESE WINDS ARE DRIVEN BY THE GRADIENT BETWEEN THE 1024 MB HIGH PRES SYSTEM OVER SOUTH CAROLINA AND TROUGHING OVER MEXICO AND THE SW GULF. THE AREA OF 20 KT WINDS IS EXPECTED TO GRADUALLY SHIFT E AS THE HIGH PRES SYSTEM DRIFTS E OVER THE NEXT FEW DAYS AND LOWER PRES BUILDS TO THE S OVER THE CENTRAL CARIBBEAN...MOVING THE TIGHTEST GRADIENT OVER THE E GULF FRI. DIURNALLY DRIVEN N-NE 15-20 KT WINDS WILL OCCUR EACH EVENING ALONG THE YUCATAN COAST TODAY THROUGH FRI. BY THE WEEKEND...THE FORECAST IS MORE DEPENDENT ON THE STRENGTH AND LOCATION OF THE LOW PRES SYSTEM IN THE CARIBBEAN. THE CURRENT FORECAST THINKING KEEPS THE LOW IN THE VICINITY OF THE GULF OF HONDURAS LATE SAT INTO MON WITH HIGH PRES TO THE N MOVING FURTHER OFFSHORE. THIS WILL KEEP THE PRES GRADIENT WEAK OVER THE NORTHERN GULF WITH WINDS BEGINNING TO INCREASE OVER THE S CENTRAL GULF SUN INTO MON. CARIBBEAN SEA... A 1009 MB AREA OF LOW PRES HAS DEVELOPED NEAR 13N69W ALONG A TROPICAL WAVE IN THE E CARIBBEAN WHICH IS ORIENTED ALONG 69W. THE WAVE AND LOW WILL MOVE FROM THE E CARIBBEAN INTO THE CENTRAL CARIBBEAN TONIGHT AND THU...POSSIBLY AS A TROPICAL CYCLONE...AND INTO THE W CARIBBEAN BY FRI. BASED ON THE NOON CONFERENCE CALL BETWEEN NHC AND HPC...THE LOW IS EXPECTED TO MOVE INTO CENTRAL AMERICA FRI NIGHT INTO SAT AND SLOWS THE SYSTEM OVER THE GULF OF HONDURAS SUN INTO MON. OTHERWISE A TIGHT PRES GRADIENT BETWEEN THE WAVE/LOW AND ATLC RIDGING TO THE N-NE OF THE AREA WILL RESULT IN 20-25 KT TRADES IN THE VICINITY OF THE WAVE WITH SEAS BUILDING TO AROUND 13 FT THROUGH THE WEEKEND. SQUALLY WEATHER IN SCATTERED SHOWERS AND TSTMS WILL OCCUR WITHIN 300 NM OF THE WAVE AXIS TONIGHT AND TOMORROW AND MAY CONSOLIDATE NEAR THE LOW IF IT DEVELOPS. SW N ATLC AND TROPICAL N ATLC... LARGE SWELLS GENERATED FROM LONG DEPARTED AND NOW EXTRATROPICAL IGOR REMAIN 7-10 FT OVER THE W PORTION OF THE WATERS. THESE SWELLS WILL CONTINUE TO SUBSIDE THROUGH THU AS SHORTER PERIOD SEAS BECOME MORE PREDOMINANT. RIDGING WILL CONTINUE TO BUILD JUST N OF THE AREA WITH MODERATE TO FRESH TRADES FOUND ACROSS THE REGION UNTIL THE WEEKEND WHEN THEY WILL GRADUALLY DIMINISH AS HIGH PRES SHIFTS E AND THE LOW S OF THE AREA IN THE CARIBBEAN MOVES W...DECREASING THE PRESSURE GRADIENT. THE STRONGEST WINDS ARE EXPECTED OVER THE SOUTHERN PORTION...JUST NORTH OF THE WINDWARD ISLANDS. WARNINGS... SW N ATLC... .NONE. CARIBBEAN... .NONE. TROPICAL N ATLC... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER/LEWITSKY