Rain in the Buffalo area was changing to snow with 5 to 9 inches expected through 7 a.m. Tuesday. Up to 16 inches are possible in higher elevations south of Buffalo through Tuesday morning.
National Weather Service meteorologist Jeff Wood said six inches of snow fell by daybreak Monday in the higher terrain of Tug Hill, just southeast of Watertown. He says the snow will be changing to rain there later Monday morning. Winds and heavy precipitation brought scattered outages around the state. NYSEG reported more than 12,000 customers without power, with many in the Southern Tier.
Flood watches were up around eastern New York after heavy rain overnight.
In Pennsylvania, the sudden burst of winter is expected to bring up to a foot of snow in higher elevations inland, closing some schools and sparking concerns of power outages.
"It's unusual, but not unheard of," said Kevin Fitzgerald, a National Weather Service meteorologist in State College, Pa., where the eastern part of the state saw rain, and the west, northwest and higher elevations dealt with snow.
Up to 12 inches of snow was expected in the higher elevations of central and western Pennsylvania, as well as New York state, south of Buffalo. A winter storm warning was issued for parts of northeastern Ohio, where 3 to 7 inches of snow was forecast.
Some schools in western Pennsylvania were closed Monday morning ahead of the storm. Districts in the state's Allegheny Mountains began announcing closures Sunday night as the storm was expected to drop 5 to 7 inches of snow by early Tuesday morning.
Much of New Hampshire and western Maine were under a flood watch Monday with more heavy rain expected. Up to 2 to 3 inches of rain is expected in the area, with the possibility of some creeks and rivers flooding.
Sustained winds of 20-30 mph were predicted throughout the Northeast, and gusts of up to 50 mph were expected off Cape Cod, Matthew Belk of the National Weather Service in Taunton, Mass., said late Sunday.
One of the biggest concerns with the storm was the potential for power outages due to limbs and branches weighed down by heavy snow falling onto power lines.
Buffalo-based weather service meteorologist Sean Smith said the slow-moving storm could linger of the Northeast through Monday before moving out sometime Tuesday.
The Sunday storm caused plenty of disruptions. Major League Baseball postponed games in Boston, New York and Washington. The scheduled arrival of the space shuttle Enterprise in New York City was pushed back, and an Earth Day celebration at a park in Virginia Beach, Va., was canceled.
The rainfall was a welcome in parts of the Northeast, which is below normal for this time of year.
"We're down 7 or 8 inches," weather service forecaster Charlie Foley said. "This won't completely wipe out the deficit but it will certainly help."
Officials said the rain should go a long way toward alleviating drought conditions, which have helped spark several major brush fires in recent weeks.
Even Lake Champlain on the Vermont-New York border, normally close to flood stage this time of year because of rain and snowmelt, is near a record low. Just a year ago, it approached its highest level on record.
Another unseasonable nor'easter last year just before Halloween dumped up to 2 feet of wet, heavy snow that snapped tree limbs and power lines, and knocked out power to more than 3 million customers in the Northeast. In Connecticut, it broke a state record for the number of power company customers left in the dark by a single storm that had been set only two months earlier when the remnants of Hurricane Irene slammed the state as it barreled up the Eastern Seaboard.
The worst of the flooding from Irene was in Vermont and northern New York, where cleanups continue seven months later. Farmers are still grappling with crop-smothering rocks, trees, gravel and sand left behind when the flood waters receded. But the dry weather has eased the threat the debris that litters the landscape will rush downriver again.
Farther south, the rain intensified throughout the day Sunday over the Baltimore and Washington metro areas, where drivers were warned drivers to beware of low visibility and slick roadways. Boaters on the Chesapeake Bay were cautioned about the winds.
In Rockport, Mass., the storm forced authorities to halt until Tuesday a search for a missing 2-year-old girl who apparently disappeared from a beach Thursday when her mother went to retrieve a lost ball. The beach is known for strong riptides.
Authorities in New York also suspended work that began last week on digging up a basement in a search for the remains of 6-year-old Etan Patz, who disappeared in 1979 on his walk to his school bus stop. The search was to resume Monday.
Copyright 2012 The Associated Press.
IN PICTURES: Extreme weather 2012