083 WTNT24 KNHC 121455 TCMAT4 TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092018 1500 UTC WED SEP 12 2018 CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MARTINIQUE * DOMINICA * GUADELOUPE A TROPICAL STORM WATCH IS IN EFFECT FOR... * ANTIGUA * MONTSERRAT * ST. KITTS AND NEVIS * SABA AND ST. EUSTATIUS A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA... IN THIS CASE WITHIN 24 TO 36 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA... IN THIS CASE WITHIN 24 TO 36 HOURS. INTERESTS ELSEWHERE IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF ISAAC. TROPICAL STORM CENTER LOCATED NEAR 15.0N 54.7W AT 12/1500Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 15 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT. 50 KT....... 40NE 0SE 0SW 0NW. 34 KT.......120NE 100SE 20SW 150NW. 12 FT SEAS..180NE 60SE 60SW 180NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 15.0N 54.7W AT 12/1500Z AT 12/1200Z CENTER WAS LOCATED NEAR 14.7N 53.6W FORECAST VALID 13/0000Z 15.1N 56.7W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 20NE 0SE 0SW 0NW. 34 KT...100NE 90SE 0SW 120NW. FORECAST VALID 13/1200Z 15.3N 59.4W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 90NE 60SE 0SW 90NW. FORECAST VALID 14/0000Z 15.3N 62.6W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 80NE 40SE 0SW 70NW. FORECAST VALID 14/1200Z 15.4N 65.6W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 80NE 40SE 0SW 70NW. FORECAST VALID 15/1200Z 15.5N 71.0W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 70NE 30SE 0SW 50NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 16/1200Z 15.5N 75.0W MAX WIND 35 KT...GUSTS 45 KT. OUTLOOK VALID 17/1200Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.0N 54.7W NEXT ADVISORY AT 12/2100Z $$ FORECASTER BLAKE