Get ready for more wet, wild winter weather

Having already distributed a Dead Sea's worth of salt, it appears that the region's highway crews are in for another night of it.

A mix of wet snow, sleet, and plain rain is expected during the day, starting before daybreak Wednesday. Then, on what could become one of the wildest nights in a wild winter, mixed precipitation is due to give way to heavy, wet snow, with several inches possible in a compressed period, complete with thunder and lightning.

The National Weather Service has placed the entire region under a winter-storm watch with a potential for 4 to 8 inches in the immediate Philadelphia area.

"It's all going to come fast," said Henry Margusity, a meteorologist with AccuWeather Inc., the commercial service in State College, Pa. Quick-moving storms have been a leitmotif of the winter of 2010-11, and this one looks to do its maximum mischief in five or six hours. Margusity said he would not rule out "thunder-snow" - a snow thunderstorm.

A wintry mix was forecast to spread across the region during the day as a storm approached from the Gulf of Mexico and tracked toward the coast.

Later, it was expected to give way to a potent storm off the Mid-Atlantic coast that would cool off the atmosphere and change the precipitation to all snow.

The accumulation forecasts bumped up significantly on Tuesday, and that may have been related to the touch of snow that powdered parts of the region in the morning, said Louis J. Uccellini, director of the National Centers of Environmental Prediction.

He said that snow was set off by a small storm that perturbed the atmosphere just enough to lock in colder air all the way to northern Virginia, making snow more likely. Earlier forecasts were based on most of the precipitation falling as rain.

Given the volatility of the computer models and the storm's complexities, don't be surprised if the forecasts change further during the day.

"This is an atypical event," said Gary Szatkowski, meteorologist in charge of the National Weather Service office in Mount Holly. "There's always some kind of surprise."