326 WTNT34 KNHC 111740 TCPAT4 BULLETIN Tropical Storm Isaac Intermediate Advisory Number 16A NWS National Hurricane Center Miami FL AL092018 200 PM AST Tue Sep 11 2018 ...ISAAC CONTINUES MOVING WESTWARD... SUMMARY OF 200 PM AST...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...14.6N 50.4W ABOUT 725 MI...1165 KM E OF THE LESSER ANTILLES MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The meteorological service of Antigua and Barbuda has issued a Tropical Storm Watch for St. Kitts and Nevis. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Watch is in effect for... * Guadeloupe * Martinique * Dominica A Tropical Storm Watch is in effect for... * Antigua * Montserrat * St. Kitts and Nevis A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests elsewhere in the Leeward Islands should monitor the progress of Isaac as additional watches could be issued this afternoon or evening. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 PM AST (1800 UTC), the center of Tropical Storm Isaac was located with high-resolution GOES-16 visible satellite data near latitude 14.6 North, longitude 50.4 West. Isaac is moving toward the west near 16 mph (26 km/h), and this motion is expected to continue for the next few days. On the forecast track Isaac is anticipated to move near or over the central Lesser Antilles on Thursday and move into the eastern Caribbean Sea Thursday night. Maximum sustained winds remain near 70 mph (110 km/h) with higher gusts. Isaac is expected to be near hurricane strength when it moves through the central Lesser Antilles, with some weakening forecast afterward on Friday. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 996 mb (29.42 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Isaac is expected to produce total rainfall accumulations of 3 to 5 inches with isolated amounts near 10 inches across the southern Leeward Islands late this week, with 1 to 2 inches anticipated across portions of the Windward Islands. STORM SURGE: A storm surge of 2 to 4 feet above normal tide levels is possible near and to the north of where the center moves through the Lesser Antilles. Near the coast, the surge will be accompanied by large and destructive waves. WIND: Hurricane conditions are possible within the hurricane watch area by Thursday morning, with tropical storm conditions possible early Thursday in both the hurricane and tropical storm watch areas. SURF: Swells generated by Isaac will begin to affect portions of the Lesser Antilles on Wednesday afternoon. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 500 PM AST. $$ Forecaster Blake