Storm strength, speed could mean snow heaps or mere dusting

Snowfall could accumulate 1 to 3 inches on grassy and elevated surfaces in the Triangle before the winter weather system quickly tracks off the North Carolina coast by early Friday morning.

Some forecasting models show as many as 4 inches of snow falling in Raleigh to 5.5 inches in Roxboro, but WRAL Chief Meteorologist Greg Fishel said accumulation will all depend on how hard the storm hits.

“The ground is very, very warm, and if it doesn't snow hard enough to overcome that warm ground, then that’s going to cut the amounts down," he said. "If it snows really, really hard for two or three hours, which it could in many areas, especially from the Triangle north and west, then that could overcome the warm ground and pile up the snow.”

The National Weather Service issued a winter storm watch for Wake, Durham, Chatham, Franklin, Granville, Halifax, Orange, Person, Vance, Warren and several other North Carolina counties from 6 p.m. Thursday until 4 a.m. Friday. 

Precipitation was already falling Wednesday evening and is likely to continue through Thursday evening.

"Right now, we already have patches of light rain and drizzle," Fishel said. "It's just miserable out there."

As temperatures fall Thursday night, the rain is expected to transition over to sleet or snow.

"By 10 o'clock, most of us will have turned over to snow here in the Triangle area. If you haven't, to the south and east, you will as we head toward midnight and the wee hours of the morning," Fishel said.

"By 3 a.m., it's gone. So, this is going to be a quick hit."

A 90 percent chance of some precipitation will linger overnight and the forecast for Friday morning sees the temperature dip just below freezing. That means Friday morning's commute will be slick, now matter how hard it snows, WRAL meteorologist Nate Johnson said.

Ice could build up on bridges and other elevated areas, so drivers should be cautious Thursday night and Friday morning.

The Department of Transportation doesn't pre-treat roads in a situation like this, because anything they spread to prevent freezing would simply wash away in the rain. If roads get icy Friday morning, crews will spread sand to help with traction. In Raleigh, city spokeswoman Jayne Kirkpatrick said some workers had been advised that they might be called in to help clear streets for Friday traffic. 

The weather warms back up to what's "normal" for the weekend, with highs in the mid to upper 50s and cold nights. By then, skies will be clear and the snow lovers will again be in wait-and-see mode.