“We’re asking everyone who can to stay off the roads,” Governor Deval Patrick said during a news conference in the Massachusetts Emergency Management Agency bunker in Framingham.

Patrick cautioned that some coastal areas could see tide surges of up to 10 feet. Massachusetts could experience widespread moderate coastal flooding, the governor said, and major flooding in pockets. With beach erosion likely, officials are considering evacuating parts of coastal areas, making determinations on a street-by-street basis.

Forecasters say the worst winds will arrive in Massachusetts after noon Monday, hours before Hurricane Sandy makes landfall in New Jersey, expected around midnight or soon after. Falling trees and branches are expected take down power lines, creating more extensive outages than were experienced last year during Hurricane Irene.

The storm’s anticipated duration of 18 to 24 hours also separates Sandy from Irene, which brought less wind but more rain, particularly in hard-hit Vermont.

“We haven’t seen things this bad in quite a while,” said Ken Haydu, a meteorologist with the National Weather Service in Taunton. “We’re going to see a lot of trees down.”

The Boston area is expected to get 1 to 2 inches of rain, and 1 to 3 inches could fall in Worcester and further west. Some isolated pockets in the western part of the state could see up to 5 inches.

The storm also is curtailing travel by air, train, and bus. State agencies and businesses asked passengers to check websites and schedules for airlines, Amtrak, and bus companies before leaving home.

On Sunday evening, President Obama signed an emergency declaration for Massachusetts, ordering federal aid to supplement state and local efforts.

Utilities, meanwhile, called in extra crews from as far away as the West Coast and canceled vacations for employees.

Across the region, shoppers filled grocery and hardware stores, and at least one man drove from New Jersey to Boston because, he said, every other Home Depot along the way had sold out of generators.

The storm prompted Suffolk Superior Court Judge Jeffrey Locke to postpone for at least a day the start of Dwayne Moore’s retrial on charges that he murdered four people in Mattapan in 2010.

The worst winds will bring hurricane-force gusts of up to 60 to 80 miles per hour, and “you could see one or two gusts reaching up to 90, especially along the coast, where they’re more exposed,” Haydu said.

On Sunday afternoon, Harwich was among the first communities in Massachusetts to report that homes and businesses had lost power because of winds hitting in advance of the storm, which the National Weather Service said is arriving sooner than expected.

As its center cooled, the storm expanded faster than anticipated, Haydu said, but its intensity did not wane.

Alberto Robles arrived in Boston from Bridgewater, N.J., on Sunday to buy the last generator available in the Home Depot in Dorchester. He had ordered it online after learning that every New Jersey store had sold out.

“Pretty much all of the stores going west all the way out to Ohio . . . were all sold out, so we had to start going up,” he said. “I wouldn’t be doing it except for the high winds they’re saying will come in, especially in New Jersey.”

In Scituate, officials said the town was preparing for “potential major impacts’’ from Hurricane Sandy and warned that residents could lose power for as long as five days. Scituate schools will be closed Monday; the high school was scheduled to open as a shelter Sunday night.

“Please be advised that if you do lose power, you should anticipate at least 72 hours before it will be restored,” Scituate officials said on the municipal website.

Police issued a voluntary evacuation order for all residents of Plum Island in Newburyport. The American Red Cross planned to open a shelter at the Newbury Elementary School Sunday, and a regional pet shelter was set to open at the same time in the Newburyport animal shelter. Officials urged residents to evacuate before 9 a.m. Monday, because emergency services will not be able to access Plum Island for several hours at the height of the storm.