000 AGXX40 KNHC 191811 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 215 PM EDT FRI AUG 19 2011 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... AN E-W RIDGE WILL MEANDER ACROSS THE N WATERS THROUGH THE PERIOD WITH LIGHT AND VARIABLE WINDS GENERALLY N OF 28N NEAR THE RIDGE AXIS. EASTERLY WINDS WILL PULSE AT 10 TO 15 KT...SEAS 1 TO 3 FT...ELSEWHERE WITH THE DIURNAL EFFECTS THIS EVENING AND SAT EVENING ALONG THE NW YUCATAN COAST. REMNANTS OF TD EIGHT WILL CONTINUE W INLAND MEXICO SUN AND MON WITH A TROUGH EXTENDING N OVER THE BAY OF CAMPECHE ACCOMPANIED BY AT 10-15 KT NE TO SE WIND SHIFT. SE SWELL...SEAS TO 4 FT...WILL MIGRATE NW THROUGH THE YUCATAN CHANNEL SAT AND SUN. N ATLC S OF 31N W OF 55W AND TROPICAL ATLC S OF 22N W OF 55W... A WEAK TROUGH OVER THE NW WATERS IS ACCOMPANIED BY A 5-10 KT WIND SHIFT ALONG THE AXIS AND SW 15 KT AHEAD OF THE TROUGH...ALL EXPECTED TO DISSIPATE THIS AFTERNOON. A RIDGE EXTENDS ROUGHLY FROM BERMUDA TO CENTRAL FLORIDA WITH THE GRADIENT MAINTAINING E 15-20 KT WINDS THROUGHOUT THE SOUTHERN BAHAMAS. EXPECT THE RIDGE TO WEAKEN TONIGHT WITH E WINDS AT 10-15 KT AROUND RIDGE PERIPHERY THROUGH SAT NIGHT. WINDS WILL BEGIN TO BACK TO THE NE AND INCREASE OVER THE WATERS S OF 25N BETWEEN 65W AND 55W EARLY SAT NIGHT AS A SIGNIFICANT TROPICAL WAVE APPROACHES THE AREA FROM THE SE. GFS GUIDANCE CONTINUES TO BE AGGRESSIVE. USED NHC TROPICAL GUIDANCE TO MOVE DEVELOPING LOW NEAR 13.5N47W...WITH TROPICAL CYCLONE POSSIBILITY...TO REACH NEAR 15N55W LATE TONIGHT...NEAR 15N54W SUNRISE SAT...NEAR 17N60W SUNRISE SUN...NEAR PUERTO RICO SUNRISE MON...NEAR NE HISPANIOLA SUNRISE TUE...AND NEAR EASTERN CUBA SUNRISE WED. TONED DOWN THE STRENGTH OF THE WINDS TILL DEVELOPING LOW BECOMES BECOMES WELL DEFINED. SYSTEM SHOULD BRING SIGNIFICANT RAINFALL TO NE CARIBBEAN. CARIBBEAN SEA... TD 8 JUST UPGRADED TO TS HARVEY OVER THE E GULF OF HONDURAS IS JUST FAR ENOUGH OFFSHORE TO ALLOW FURTHER STRENGTHENING AS IT TRACKS W AND INLAND BELIZE AROUND SUNSET SAT. CONVECTION HAS REMAINED ORGANIZED N SEMICIRCLE WITH THE SYSTEM TRACKING ALMOST DUE W...THUS EXPECT SOME TRAPPED FETCH SWELL. SO WILL BUILD SEAS TO 14 FT PRIOR TO LANDFALL BUT IN EXPOSED AREAS N OF ISLANDS INCLUDING ROATAN. REFER TO WTNT23 KNHC/TCMAT3 FOR FURTHER DETAILS AND UPDATES ON TS HARVEY. ELSEWHERE MAINLY MODERATE TRADES WILL REMAIN OVER THE CARIBBEAN THROUGH EARLY SAT. LOW PRES IS DEVELOPING ALONG A TROPICAL WAVE NEAR 13.5N47W...WITH TROPICAL CYCLONE FORMATION A POSSIBILITY. WILL USE NHC TROPICAL CYCLONE GUIDANCE TO MOVE THE LOW NW ACROSS THE LEEWARDS SUN AND MON AND THROUGH THE ANTILLES TUE INTO WED. UNCERTAINTY IN STRENGTH AND TRACK...THUS MUCH UNCERTAINTY IN WIND FIELD AND ASSOCIATED SEAS OVER THE N CARIBBEAN THIS WEEKEND. MARINERS SHOULD EXPECT PLENTY OF ADJUSTMENTS EACH FORECAST PACKAGE. LARGE RANGE OF WINDS OF TO 15 TO 25 KT AND SEAS 6-10 FT REFLECT LITTLE CONFIDENCE IN GUIDANCE. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROPICAL N ATLC... .AMZ082...TS WARNING 16N-18N W OF 84W THROUGH LATE SAT. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER NELSON