Starting this morning, the region faces a blast of arctic air and small snowfalls that could make driving dicey in the year's closing days.

The National Weather Service issued a winter weather advisory for most of the region from 10 last night until 7 p.m. today and said 2 to 4 inches of snow was expected by this evening. Snowfalls could be a bit heavier in the Laurel Highlands.

The frigid weather could be with us awhile, forecasters said.

A cold front that's going to take the bottom out of yesterday's high temperature of 42 has the potential to make driving even more treacherous than today's early-morning coat of snow.

"Just after [tonight's] rush hour I'd start to be worried as an Arctic front dives into the region," said Mike Pigott, meteorologist for AccuWeather, based in State College. "When that happens, you're looking at heavier snow and extremely cold and windy conditions that produce severe snow squalls. They can produce white-out conditions."

Meteorologist John Darnley of the National Weather Service here said the high temperature would be 28 today and 24 tomorrow. Mr. Pigott said wind would make it feel as if the temperature were in single digits.

Highs in the low to mid-30s are expected Wednesday and Thursday with a high of 30 expected on New Year's Day, Mr. Darnley said.

"For this time of year, it's going to be below normal," he said. "The normal for this time of year is right around 37 for the maximum, and the low normal temperature is 23."

The snow isn't going to go away; it's going to come in dribs and drabs.

"Accumulations will come at a coating to an inch at a time [in Pittsburgh]," Mr. Pigott said. The eastern highlands will get 1 to 2 inches at a time.

Though the forecast could change, it looks like that will be the case for New Year's Eve.

"There's a cold front coming through. There will be light snow that day," Mr. Pigott said. "It looks like it will accumulate an inch at the moment. An inch isn't treacherous, but it's not dry, either. It's just enough to start minor problems."

AccuWeather is forecasting "major storms with snow" in the Northeast over the coming weeks, but Pittsburgh should be outside the storm track, Mr. Pigott said.

"The storms being referred to will hit the East Coast and the mid-Atlantic area, the I-95 corridor," he said. "January could start off pretty active [there]."

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