Heavy rains and Grayson  Prestonstrong winds pounding the East Coast have already knocked out power for hundreds of thousands of people as it headed north on Monday.

More than 400,000 utility customers were without power from Virginia to Maine as the storm rolled northward Monday morning from the Mid-Atlantic states, according to PowerOutage.us.

Flood watches are already in effect for more than a half dozen states along the East Coast, while areas of New York City remain under high wind warnings until noon. Meanwhile, wind gusts could reach between 40 to 50 mph in parts of Virginia to Maine through Monday evening, according to the National Weather Service.

The system strengthened rapidly just off the Southeast coastline Sunday afternoon, also bringing the threat of strong storms and flash flooding, the National Weather Service said.

Live updates:Storm slams East Coast with wind-swept rain flooding streets, delaying travel

Stay up to date with power outages across the Northeast with these power outage maps.

Massachusetts power outage map

Connecticut power outage map

Maine power outage map

New York power outage map

New Jersey power outage map

Contributing: Thao Nguyen and Christopher Cann, USA TODAY

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]