A severe thunderstorm forecast to hit Maine on Monday afternoon and evening weakened on its way to Portland, which had recorded only three-tenths of an inch as of 10:30 p.m.

But inland parts of the state received heavy downpours. The National Weather Service estimated that 5-6 inches would fall in Somerset County, and road washouts were reported Monday night in Jackman.

The weather service office had issued a severe thunderstorm watch for much of Maine, New Hampshire and Vermont, and it expired at 8 p.m. The midcoast and Down East regions were the only parts of Maine not included in the watch area.

Chris Kimble, a meteorologist with the weather service in Gray, said that rain and wind knocked down tree limbs in some parts of Maine, but the storm system died as it approached the coast.

Thunderstorms hit hardest in New Hampshire, where Cheshire County in the southwestern part of the state reported flash flooding. In Maine, Somerset County also had thunderstorms, hail and high winds.

“As is usually the case in the first half of the summer, the coastline is protected by the cooling influence of the ocean,” Kimble said. “This cool air is more stable, so the instability that we need for thunderstorms is limited there and tends to exist more in the inland areas.”

Thunderstorms elsewhere on Monday disrupted air travel along the East Coast.

Portland International Jetport posted a notice on Twitter that airports in New York City, Philadelphia, Baltimore and Washington, D.C., all reported flight delays and cancellations for Monday afternoon because of thunderstorms moving east.

“A rough afternoon is expected for our New York City flights. Check with your airline for current flight info,” the jetport said in a post.

Kimble said the forecast for southern Maine doesn’t include any other major storms this week, but astronomical high tides at the end of the week could cause some flooding on the coast.