A treacherous, potentially dangerous snowstorm is bearing down on us.

Snow will start falling this afternoon. Wednesday, the snowfall will kick into gear, and be goosed by high winds.

Those who can stay home should, officials are saying.

The approaching storm could be  "the real blizzard of 2010," said Millersville University meteorologist Eric Horst.

MU, AccuWeather and the National Weather Service all are calling for 10 to 18 inches of snow to fall here today and Wednesday.

But it's the high winds on the back half of the storm that will wreak havoc here, as they will cause drifting and possibly blizzard conditions.

VIDEO: AccuWeather Forecast

"It's really going to be ugly," said Scott Tanguy, the state transportation maintenance manager for the county. "People think, 'We've dealt now with 20-plus inches in December and 20-plus inches just this past weekend.'

"But this storm is a whole different animal."

While the weekend storm brought drifts of 2 to 3 feet, the coming storm could bring drifts of 8 to 10 feet, he said.

"This is impressive," Horst said.

The storm is expected to close schools and possibly some businesses. The city and several boroughs already have declared snow emergencies.

The storm could meet the meteorological criteria for a bona fide blizzard: 35 mph wind speeds sustained for three hours, or frequent gusts above 35 mph, as well as visibility below a quarter of a mile for three hours or more.

Blizzard conditions are not dependent on the amount or type of snow, Horst said, but are created by blowing snow.

Winds of 20 to 40 mph are possible. That's twice the speed of the winds of the weekend storm but technically carrying four times the amount of energy, he said.

So folks who wake up to 6 to 8 inches of snow Wednesday morning may be able to get to work, but getting home could be very dangerous, Horst said.

"The heaviest snow will be falling tomorrow morning into the mid-day hours," he said.

It's a storm where a driver "could get on the interstate," he said, "and get stranded. Just stay home. Don't even think about traveling after midnight tonight."

Winds finally will slack off Thursday afternoon, but that means a 24-hour period of drifting and major headaches for road crews, motorists and possible power line crews.

 "This will be much more impactful (than the weekend storm) even though on the measuring stick it may not be that much," Horst said.

Once again, as it did last weekend, the state transportation department is urging people to stay off the roads whenever possible.

Motorists who must travel are urged to take a cell phone, blankets, warm clothes and food in case they get stranded.

"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, PennDOT's deputy secretary for highway administration.

In addition to dealing with drifting snow, road crews also will face another headache, Tanguy said.

"We're out of room," he said, noting the significant amount of snow already on the ground.

PennDOT was trying today to line up emergency equipment, such as large loaders that could stack the snow a little higher, he said.

Residents, he added, need to be realistic about how quickly crews will be able to clear roads.

"If you're on one of those secondary roads that typically drifts, we're going to do our very best to keep it open," he said, but said some roads may be impassable at times.
cstauffer@lnpnews.com