The forces of nature are conspiring to kick us while we're down.

With the region still reeling from a historic weekend storm, another snow-spewing system was preparing to barrel through starting this morning, and officials struggled to get ready even as they worked at clearing roadways of snow, ice, slush and downed trees and power lines.

The National Weather Service issued a winter storm warning starting at 10 a.m. and predicted 6 to 10 inches of accumulation through Wednesday afternoon.

Road crews and public transportation providers were girding for yet another long day, many universities and school districts canceled classes and many businesses and cultural attractions announced closures in anticipation of "Snowmageddon -- the Sequel."

The city announced that all Public Works crews will focus on plowing the secondary roads to try to provide access to all neighborhoods. As of 4 p.m. Monday, crews had cleared roughly 50 percent of the city's secondary roads, the mayor said at a press conference. At 10 a.m., that number was at roughly 15 percent.

"We're doing everything we can to get a handle on our roads in order to position ourselves for this next storm," Mr. Ravenstahl said.

"Our goal is to have every secondary street touched by [today's] storm. In addition, it's all hands on deck. Firefighters, police, paramedics, and PA National Guardsmen will be out in the neighborhoods assisting the elderly and anyone who needs support."

Monday's predictions sounded eerily similar to those that preceded the 21.1-inch storm that began Friday.

This storm likely will be "a little more drawn out" but less intense, said meteorologist Kerry Schwindenhammer of AccuWeather in State College.

Like the weekend storm, this snowfall will be of the wet, heavy variety, he said. It was expected to fall steadily until midday Wednesday but intermittent snow showers will persist into Thursday.

Winds should pick up Wednesday, causing blowing and drifting snow. Temperatures will be low enough that the storm will be all snow with no rain or sleet, Mr. Schwindenhammer said.

The National Weather Service, in an advisory Monday afternoon, said "there is still much uncertainty with the exact track and timing of the storm, both of which will greatly affect snowfall accumulations."

Brad Rehak of the weather service said winds could gust at 30 to 35 mph on Wednesday, producing wind chills at or near zero.

"We see no extended warm periods in the near future," he said.

Jim Struzzi, spokesman for the Pennsylvania Department of Transportation, said crews are concerned about where they are going to push the new snow.

"There's so much snow out there now. It's really piled up," he said.

Plows were trying to clear shoulders of main highways to make room for whatever comes today.

They also were repairing equipment that took a pounding over the weekend from the weight of the snow, Mr. Struzzi said.

"I'm sure they're stressed," he said of the department's plow operators.

"We've all been going pretty much nonstop since Friday. But that's what we do."

The city called in 10 Allegheny County and PennDOT front loaders, and using a city council-approved emergency declaration entered into fast-tracked contracts with private firms who brought in another 10 trucks to help clear snow.

The mayor also asked any contractors with extra heavy equipment to call 412-473-2550 to make arrangements to work with the city.

He said the city is also bringing in equipment to double the number of phone lines of the city's overloaded 311 response system.

Residents can also make requests for tree removal or necessary transport by logging onto www.pittsburghpa.gov and clicking on "311." Residents can sign up for public safety alerts at this site.

Around the region, individuals and institutions got ready for round two.

Mayoral spokeswoman Joanna Doven said that the director of public safety asked that all colleges and universities in the city close today. Those schools have agreed.

Counties in the region still dealing with major power outages prepared for more snow.

"We're going to switch modes at get ready for the next batch of snow," said Susan Griffith, Fayette County's emergency management director. "We have a little bit of notice and we say, 'Stay prepared. Don't panic.' We have to put that into practice."

PennDOT issued a statement Monday urging motorists to avoid unnecessary travel.

"The reality is that motorists who must travel Tuesday night and during the day on Wednesday will face conditions possibly worse than those seen over the weekend due to the strong, gusty winds currently forecast," said Scott Christie, deputy secretary for highway administration.

PennDOT postponed construction and maintenance projects that were scheduled this week on the Parkway East, Interstate 79 and West Carson Street, and in the Liberty Tunnels. There will be no overnight closures of the inbound tunnel this week.

The Port Authority had limited service Monday and that was likely to continue this morning, spokesman Jim Ritchie said. Some 60 routes were not in service because of poor road conditions. All of the 100 routes that did operate experienced delays, he said.

Information on which routes are operating is on the authority's website, portauthority.org.

Mr. Ritchie said the authority expects to have all of its park-n-ride lots open today. Some were closed Monday because snow hadn't been removed.

Light Rail Transit trips had to be terminated at First Avenue throughout Monday because of a power outage in the Downtown subway. Mr. Ritchie said he did not know whether the problem would be fixed by this morning's rush.

He said he couldn't predict what will happen this afternoon if the storm arrives as forecast.

"We will try to provide service as long as we can," he said.

Pittsburgh City Council postponed its meetings scheduled for today and Wednesday. Both are to be held Thursday.

The Carnegie Science Center said they would be closed today, and the Pittsburgh Zoo and PPG Aquarium will be closed through Friday. Tracy Gray, a zoo spokeswoman, said ground crews were working to remove snow from pathways and parking lots.

She said the animals were doing well, and some, like the polar bears and tigers, were enjoying the snow and cold weather.

The double-whammy of storms also caused a run on snow shovels. Several stores, including the Home Depots in East Liberty and Ohio Township, the Kmart in Shaler and the Walmart in Scott and Cranberry, said Monday they had sold out.

Doug Satterfield, a co-owner of Rollier's Hardware on Washington Road in Mt. Lebanon, said he sold more than 300 shovels starting Saturday morning before running out.

The store has ordered more, he said, and by this afternoon hoped to have 250 in stock, along with more ice scrapers, melting agents and portable heaters.

See the PG's weather page for the latest conditions and forecast -- and the Countdown till Spring clock. Commuters also can access the updated traffic conditions.

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