587 WTNT24 KNHC 130855 TCMAT4 TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092018 0900 UTC THU SEP 13 2018 CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... THE GOVERNMENT OF ANTIGUA HAS ISSUED A TROPICAL STORM WATCH FOR BARBUDA 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 * BARBUDA * MONTSERRAT * ST. KITTS AND NEVIS * SABA AND ST. EUSTATIUS * ST. MARTIN AND ST. MAARTEN A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA... IN THIS CASE WITHIN THE NEXT FEW HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA... IN THIS CASE WITHIN THE NEXT FEW HOURS. INTERESTS ELSEWHERE IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF ISAAC. TROPICAL STORM CENTER LOCATED NEAR 15.4N 59.7W AT 13/0900Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 15 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT. 34 KT.......140NE 0SE 0SW 140NW. 12 FT SEAS..150NE 30SE 30SW 150NW. 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 15.4N 59.7W AT 13/0900Z AT 13/0600Z CENTER WAS LOCATED NEAR 15.3N 58.8W FORECAST VALID 13/1800Z 15.5N 61.8W MAX WIND 35 KT...GUSTS 45 KT. 34 KT...120NE 0SE 0SW 120NW. FORECAST VALID 14/0600Z 15.5N 64.8W MAX WIND 35 KT...GUSTS 45 KT. 34 KT...100NE 0SE 0SW 100NW. FORECAST VALID 14/1800Z 15.5N 67.8W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 80NE 0SE 0SW 80NW. FORECAST VALID 15/0600Z 15.4N 70.4W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 70NE 0SE 0SW 70NW. FORECAST VALID 16/0600Z 15.6N 74.8W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 70NE 0SE 0SW 70NW. 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 17/0600Z 16.9N 78.5W MAX WIND 30 KT...GUSTS 40 KT. OUTLOOK VALID 18/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.4N 59.7W NEXT ADVISORY AT 13/1500Z $$ FORECASTER ZELINSKY