What is now Tropical Storm Elsa is moving towards the Northeast and will enter the Gulf of Maine as an extra-tropical cyclone Friday, according to the National Weather Service.

Heavy rainfall and potential flash flooding remains the greatest threat. Generally, 1 to 3 inches of rain is expected Thursday and Friday.

The National Weather Service issued a flash flood watch from 8 p.m. Thursday through Friday evening. Conditions may develop that lead to flash flooding.

Rainfall rates will increase to as much as 1 inch per hour by late Friday morning. Some areas may experience heavier rainfall, leading to the threat of flash flooding. The heavy rain could cause smaller rivers and streams to quickly rise. There is also the potential for flash flooding in areas of poor drainage.