A “powerful” storm lashed the mid-Atlantic coast Monday morning with heavy rain and thunderstorms, leaving 59 million people from Virginia to Maine under flood alerts, 200,000 homes and businesses without power, and holiday travelers scrambling as airports report flight delays and cancellations. 

There’s a slight risk of excessive rainfall over parts of New England through Tuesday, the National Weather Service’s Weather Prediction Center warned.

“The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable,” the weather service said. 

The same storm system battered Florida and the Carolinas with strong winds and torrential rain over the weekend — with Charleston breaking a daily record Sunday with 3.86 inches of rainfall and Gainesville, Florida, recording more than 7 inches.

The East Coast is already reeling from the impacts with more than 250,000 people across New England and New York without power as of 8 a.m., according to PowerOutage.us.

In New York City, a travel advisory is in effect due to flooding conditions on roads, power outages and high winds on bridges. The city’s emergency management office also warned of “imminent” flash flooding in Manhattan and the Bronx, warning locals to avoid basements and low-lying areas. 

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“Please exercise caution with your morning commute. Take mass transit and stay off the roads if possible,” Mayor Eric Adams tweeted. 

There’s more than 500 delays nationwide and more than 370 cancellations, a number likely to keep growing Monday ahead of holiday travel chaos that sees millions take to the skies a week ahead of Christmas, according to FlightAware data. It comes after a weekend that saw a dizzying number of delays — more than 10,000 — and almost 200 cancellations.

The threat of heavy rain will end Tuesday as the system moves further into Canada by Monday evening. 

Lake-effect snow downwind of the Great Lakes and upslope snow over parts of the northern and the central Appalachians are also in the forecast Monday through Wednesday, the weather service said.

The heaviest snow Monday will fall over parts of the central Appalachians, southwest of Lake Michigan in Michigan and Indiana, and along the central and the eastern shores of Lake Erie in Ohio and New York. The lake-effect snow will lighten up Tuesday and end over the upper Great Lakes, forecasters said.

This is a developing story. Please check back for updates.