About 300,000 without power in U.S. southeast after storm

ATLANTA, Dec 10 (Reuters) - About 300,000 people in the U.S. southeast were without power on Monday and hundreds of flights were canceled after a storm dumped 20 inches of snow and left one motorist dead.

The storm headed out to sea but the region will stay cold this week, the National Weather Service's (NWS) Weather Prediction Center said.

"This remains a dangerous system even as it moves off the coast," said lead NWS forecaster Michael Schichtel. "It's slow to move off the Carolinas but a saving grace is that it won't hit New England."

One motorist died outside Charlotte, North Carolina, on Sunday, and divers searched for a driver whose 18-wheeler was found in a river in Kinston, North Carolina, a NBC affiliate in Raleigh reported.

Motorists in north Georgia, the Carolinas and Virginia can expect snow and ice on Monday.

More than 300,000 customers were without power in the Carolinas, Tennessee and Virginia, Poweroutage.us reported.

The storm prompted more than 1,000 flight cancellations at Charlotte/Douglas International Airport, the sixth-busiest airport in the country, and other airports across the region, according to flight-tracking website FlightAware, early Monday.

North Carolina Governor Roy Cooper said on Sunday a state of emergency would remain in effect and the North Carolina National Guard had been activated to help with the response.