Much of the north-eastern United States braced for heavy rains and flooding as Tropical Storm Fay was expected to sweep across the heavily populated region on Friday, the National Weather Service said. The weather system, which reached tropical storm strength on Thursday afternoon with sustained winds of 64 kph, was already drenching several Mid-Atlantic states even before making landfall, the NWS said. Several beaches in Delaware were closed temporarily due to the storm. And police in Ocean City, Maryland, asked drivers to avoid southern parts of the tourist town because flooding had already made some roads impassable. “The main impact is not going to be the wind,” meteorologist Laura Pagano told Reuters. “It’s actually going to be associated with the rainfall.” Five to 10 centimetres of rain were expected through most coastal areas of Delaware, Maryland, New Jersey and eastern Pennsylvania before the storm is forecast to hit the New York City area later on Friday, Ms Pagano said. “We expect some pretty heavy winds, and we need people to be ready for that, and some flash flooding in certain parts of the city,” New York City Mayor Bill de Blasio said at a briefing on Friday morning. The summer storm’s impact on the city was expected to be "pretty limited," but Mr de Blasio said it would be a bad night for outdoor dining — the only sit-down service allowed at city restaurants because of the pandemic. “If you were going to go out tonight, instead order in and keep helping our restaurant community,” he said. Winds are expected to diminish as the storm comes ashore, especially when it reaches New York’s Hudson River Valley, Connecticut and Western Massachusetts on Saturday, but there will be a risk of localised flash flooding, Ms Pagano said. “This is going to be ongoing... through the daytime today and into the overnight hours as it continues to progress north,” she said. “The overall extent of damage should not be exceptionally widespread.” Whatever flooding the storm brings will be from its rains and not from wind-driven coastal surges, Ms Pagano added. President Donald Trump said the storm is being monitored and that the Federal Emergency Management Agency was poised to help if needed. “We’re fully prepared. Fema’s ready in case it’s bad. Shouldn’t be too bad, but you never know,” Mr Trump told reporters while departing the White House for Florida. Mr Trump postponed his Saturday rally in New Hampshire due to the weather.