New York: A potent rush-hour rainstorm swamped the New York metropolitan area on Friday, shutting down parts of the city's subway system, flooding streets and highways, and delaying flights into LaGuardia Airport. New York Governor Kathy Hochul has declared a state of emergency across New York City, Long Island, and surrounding area.

Ophelia's remnants soaked New York City with heavy rain early Friday, and caused flash flooding in parts of the city, Xinhua news agency reported. A flood watch is in effect through 6 a.m. Saturday for the entire tri-state - New York, New Jersey and Connecticut, with rainfall rates of one to two inches per hour expected at times.

Strong storms have shut down swaths of the Big Apple's subway system, flooded some streets and highways, and cut off access to at least one terminal at the LaGuardia Airport.

A number of subway lines were suspended Friday morning with other lines suspending service through flooded stations, especially in Brooklyn.

"There is only extremely limited subway service available because of heavy flooding. Service is suspended at many stations," the Metropolitan Transportation Authority (MTA)'s subway account posted on X, formerly known as Twitter.

The MTA, which runs subway and commuter rail lines, urged residents of the nation's most populous city to stay home if they could. Virtually every subway line was at least partly suspended, rerouted or running with delays, and two of the Metro-North Railroad's three lines were suspended.

Hochul's announcement on Friday was followed by a similar order from New York City Mayor Eric Adams, who asked residents to shelter in place during the worst of the storm.

"I want to say to all New Yorkers, this is time for heightened alertness and extreme caution. If you are home, stay home. If you are at work or school, shelter in place for now," Adams said.

Parts of New York City saw five inches of rain as of 11 am Friday. In Central Park, it was the most rainfall seen since the remnants of Ida swept through two years ago.

Video footage showed cars stuck in the flooded streets at the Red Hook neighbourhood in the Brooklyn borough. Some people were working to clear a drain in flood water.

A game set for Friday night between the Philadelphia Phillies and New York Mets was postponed due to severe weather.

(With IANS, PTI inputs.)