Tropical cyclone ISAAC has been downgraded to a tropical storm. On 12 September at 3.00 UTC its centre was located approximately 900 km east of Martinique and Dominica Islands (Lesser Antilles), with maximum sustained winds of 102 km/h. Over the next 24 hours, it is forecast to weaken slightly as it moves across the central Lesser Antilles and into the eastern Caribbean Sea. Heavy rain, strong winds and storm surge could affect Martinique, Dominica, and Guadeloupe over 13-14 September. A tropical storm watch is in effect for Antigua, Montserrat and St. Kitts and Nevis. Persistent intense rainfall is likely over Dominica and portions of the Northern Windwards/Southern Leewards with the possibility of flash flooding and localised landslides leading to disruptions in transportation and utilities. DG ECHO continues to monitor the situation closely.