Snarling air travel across the country and overseas, a powerful storm plastered the Northeast with snow and ice Monday, but earlier forecasts of potentially record-breaking accumulations were scaled back.

Fears that the weather system would produce as much as 2 feet of snow in New York and other coastal areas diminished as the storm failed to organize itself as dramatically as had been feared. The city was expecting only 3 to 6 inches of snow overnight.

One to 3 feet of snow still was forecast across much of New Jersey, New York state and New England by early Wednesday.

Nevertheless, schools were closed Monday for millions of youngsters from West Virginia to Maine.

The nor’easter had been forecast days in advance, and people had plenty of time to stock up on groceries, snow shovels and videos, stripping shelves bare in some stores.

“It’s like they’re never going to eat again,” Mavis McLynn said as she shopped at a supermarket in Philadelphia.

The heaviest snowfall from the slow-moving storm was expected today, but by Monday a foot or more had already fallen in upstate New York and northeastern Pennsylvania. Elsewhere, sleet and freezing rain glazed sidewalks and highways.

Meteorologists had warned that the storm could be similar to the blizzard of 1978, which buried southern New England in 3 feet of snow, caused more than 100 deaths and battered coastal areas with high waves.

But coastal flood warnings issued early in the day for the entire Jersey shore were partially lifted. Only minor tidal flooding was expected along the southern coastline.

“Sandbags aren’t going to help a bit in this case. If it comes, it’s going to come,” said emergency official Mark Zartarian at the shore town of Rye, N.H. “If it’s anything like ’78, it’s going to lift and move boulders the size of your car.”

New York’s Education Department estimated 90 percent of the state’s public and private schools were closed. Affected were 3.1 million students, including 1.1 million in New York City – despite the fact snow didn’t begin falling in the city until early evening.

“I think it’s going to rain all night,” Long Island commuter Sean Leguillo said during Monday afternoon. “I’ve been waiting since Saturday for some snow.”

The city was still bracing for snow overnight, but Mayor Rudolph Giuliani was able to joke about the weather during an afternoon phone chat with Gov. George Pataki.

“When the governor called me and he said, ‘How is the storm?’ I said to him, ‘What storm?”‘ Giuliani said.

Every school in Connecticut was shuttered, keeping more than 500,000 kids at home. In Boston, some 62,000 youngsters got the day off. Philadelphia schools closed early, and hundreds of thousands of students were sent home.

Airlines canceled hundreds of flights at the New York metropolitan area’s La Guardia, Kennedy and Newark airports, and more than 400 flights were called off at Boston’s airport. Swissair grounded flights that would have carried about 1,600 passengers to and from Europe on Monday.

Despite days of warnings from forecasters, some travelers wound up stranded at airports.

“I’ve been here so long it seems like years,” said Joshua McKinley, 21, who was among the weary travelers who spent the night on cots at La Guardia.

While utility crews and state emergency workers were on standby, nonessential government workers were told to stay home and off the roads in Connecticut, New York City’s suburbs, Massachusetts and New Jersey.

The Pennsylvania General Assembly called off Monday’s planned budget hearings.

Connecticut Gov. John G. Rowland banned jackknife-prone tractor-trailers from the state’s highways, and in Massachusetts all bus service between Cape Cod and Boston was canceled.

With the wind whistling in off the ocean, a housing project for the elderly in Revere, Mass., was ordered evacuated because of the danger of flooding. At Ocean Grove, N.J., 10-foot waves crashed against the pier and the surf sloshed much of the way across 200 yards of newly replenished beach.

“I come here every day with the dog, and I’ve never seen it come up this far,” said Bill Kearsley, 46, as he walked his Labrador retriever.