A flash flood watch remains in effect for Long Island through Sunday morning.
The National Weather Service said the worst conditions were expected Saturday evening.
Coastal flooding is expected on the South Shore during high tide Saturday night, the National Weather Service said.
These slow moving storms could bring several inches of rain and a threat of flooding, said News 12 Long Island meteorologist Pat Cavlin.
As of 3 p.m. Saturday, the Federal Aviation Administration was reporting delays for incoming and outgoing flights at Kennedy and La Guardia airports.
The FAA said that due to weather and thunderstorms, flights to La Guardia were experiencing delays averaging one hour and 36 minutes. Flights arriving to Kennedy Airport were delayed an average of 5 hours. Travelers are advised to check with their airlines.
Meteorologists said about 1 to 2 inches of rain is likely across much of the region Saturday, with 3 to 5 inches possible through tonight.
Showers will continue into Sunday and possibly into early next week, according to the National Weather Service.
Showers and thunderstorms will continue through Sunday, Monday and Tuesday, Cavlin said.
“I think Monday could really be a washout for us,” Cavlin said.