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| #939735 (Received by flhurricane at: 1:53 PM 12.Sep.2018) TCPAT4 BULLETIN Tropical Storm Isaac Intermediate Advisory Number 20A NWS National Hurricane Center Miami FL AL092018 200 PM AST Wed Sep 12 2018 ...ISAAC MOVING RAPIDLY WESTWARD... SUMMARY OF 200 PM AST...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...15.1N 55.7W ABOUT 420 MI...675 KM E OF MARTINIQUE ABOUT 345 MI...555 KM E OF GUADELOUPE MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 21 MPH...33 KM/H MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of France has issued a Tropical Storm Watch for St. Martin and the government of St. Maarten has issued a Tropical Storm Watch for St. Maarten. 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 * St. Martin and St. Maarten A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area 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. 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 by a NOAA Hurricane Hunter aircraft and satellite near latitude 15.1 North, longitude 55.7 West. Isaac is moving faster toward the west near 21 mph (33 km/h), and this general motion with a decrease in forward is expected to continue through the weekend. On the forecast track, Isaac is forecast to move across the central Lesser Antilles and into the eastern Caribbean Sea on Thursday, and then move across the eastern and central Caribbean Sea through Saturday. Aircraft data indicate that maximum sustained winds remain near 60 mph (95 km/h) with higher gusts. Gradual weakening is forecast during the next 72 hours. Tropical-storm-force winds extend outward up to 175 miles (280 km), primarily to the north of the center. The estimated minimum central pressure based on the aircraft data is 1002 mb (29.59 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Isaac is expected to produce total rainfall accumulations of 2 to 4 inches with isolated amounts up to 8 inches across Martinique, Dominica, and Guadeloupe. Rainfall of 1 to 2 inches with isolated amounts to 4 inches are forecast across Puerto Rico and the southern United States Virgin Islands, with up to an inch anticipated across the remaining Windward and Leeward Islands. This rainfall may cause life-threatening flash flooding. WIND: Tropical storm conditions are expected on Martinique, Dominica, and Guadeloupe early Thursday. Tropical storm conditions are possible within the tropical storm watch area on Thursday. STORM SURGE: Some coastal flooding is possible in areas of onshore winds. Near the coast, the surge will be accompanied by large waves. SURF: Swells generated by Isaac will begin to affect portions of the Lesser Antilles this 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 |
