City officials discuss preparations on Wednesday for the incoming winter storm. (Karl Merton Ferron/Baltimore Sun video)

Meteorologists were expecting the heaviest snowfall of an already frigid and snowy season Thursday, with the region forecast to wake up to a blanket of snow and to endure an icy mix of precipitation through the afternoon.

The National Weather Service was expecting six to 10 inches of snow across the Baltimore area by Thursday night, with higher accumulations north and west of the city. Possible sleet or rain closer to Interstate 95 and the Chesapeake Bay could reduce snowfall in those areas.

The heaviest snow was expected overnight, through daybreak Thursday, and meteorologists remained uncertain Wednesday on exactly when and to what degree warm air in the atmosphere might limit snowfall.

Officials nevertheless cautioned residents to expect snow-covered roads and possibly widespread power outages. Snow was expected to be wet and heavy, weighing on tree limbs weakened by past storms, and gusty 15-30 mph winds were expected to send branches swaying.

Many heeded the warnings by Wednesday evening as residents stockpiled provisions and school systems and state offices closed for Thursday. Flight cancellations also started piling up in advance of the storm.

Gov. Martin O'Malley warned of a "24-hour event" that will bring "a big swath of nasty snow and ice" to the state. He declared a state of emergency Tuesday, while the National Weather Service issued a winter storm warning through early Friday morning.

"Neighbors should stay off the roads," O'Malley said.

The storm was considered to be a classic nor'easter, with a moist system coming up from the Southeast and merging with colder air from the north off the Carolinas. It brought a thick layer of ice to Atlanta and snow across the western Carolinas before heading northeast toward Maryland and beyond, into New England.

It was forecast to intensify over the Mid-Atlantic, bringing snowfall rates of an inch or more per hour overnight. This snow should be unlike earlier snows this winter that were dry and fluffy amid bitter cold, with temperatures forecast to straddle the freezing mark Thursday.

"Whenever you have these situations where we're worried about a changeover to rain, it indicates the snow that's falling is going to be of the wet variety," said Randy Adkins, a meteorologist with AccuWeather.com.

Snowfalls were expected to easily surpass a foot near Westminster and Frederick, though, if air stays colder than expected, such accumulations could also be measured closer to Baltimore, forecasters said.

Baltimore Gas and Electric Co. was preparing Wednesday for widespread power outages, mobilizing its own crews and others from outside the state at staging areas across the region. The Maryland Public Service Commission said it was working with state utilities and the Maryland Emergency Management Agency to stay on top of anticipated outages.

With fresh memories of outages last week, some of which lasted for days, many people bought extra provisions. Some of the most popular purchases at Eddie's of Roland Park included cake mixes, ingredients for chili, marshmallows, frozen pizza and deli meats, said Michael Schaffer, the store's vice president.

"I'm just trying to stay one step ahead," said Caroline Pinkin as she rushed into the store Wednesday. "I'm picking up things I don't have to cook in case the power goes out."

Nearby at North Charles Fine Wine & Spirits, people were stocking up on "warm drinks" such as red wine, bourbon and whisky, said Robert Chapman, the store's manager.

Some hardware stores in the Baltimore area reported a shortage in rock salt, which people also sought.

While many were prepared to shutter themselves in their homes, the state was readying to keep roads as clear as possible, deploying about 2,700 plows and other pieces of snow removal equipment through the State Highway Administration and private contractors, O'Malley said.

Baltimore Mayor Stephanie Rawlings-Blake said the city planned to take advantage of on-call contracts it established with road crews "that can help us attack the residential streets at the same time our equipment is doing the primary and secondary roads."

"We haven't done all the analysis, but what we're hearing anecdotally is they're seeing a big difference," Rawlings-Blake said of plowing so far this winter. Baltimore city health officials extended a "code blue" advisory through Thursday, freeing up more shelter space and resources for the homeless.

In Annapolis, residents were encouraged to park their cars for free in city-owned garages to keep the historic city's narrow roadways clear for plowing crews. Residents could get snow vouchers by showing proof of residency to garage staff.