Update: Besides snow in the Rock Hill area, look out for black ice

A fast-moving weather system is expected to bring a couple hours of snowfall to the Rock Hill area early Wednesday, possibly coating roadways with a light accumulation, forecasters say.

The snow could continue through the morning commute, they add.

While emphasizing words like “might” and “light” with the system, National Weather Service meteorologists say there is growing confidence that snowflakes will be falling in the Rock Hill area for a few hours Wednesday.

They also say black ice could be an issue late Wednesday night and Thursday morning.

The Weather Service’s Sandy LaCorte says a half-inch is expected across much of the Upstate and Piedmont, but he adds, “Some locations, especially east of I-77, could see slightly higher amounts toward an inch.”

Heavier amounts of 2 or 3 inches are forecast for the North Carolina mountains and in the Greensboro area.

While amounts are not predicted to be significant, timing could be an issue. Precipitation is expected to start as rain late Tuesday night, then change to snow in the early-morning hours Wednesday. That means snow could be falling, and possibly causing slippery roads, during the morning commute.

Forecasters say the band of snow will accompany a cold front pushing southeast across the Carolinas late Tuesday and Wednesday. These fast-moving “clipper” systems typically are moisture-starved, but computer guidance indicates this disturbance might produce enough precipitation to coat the ground.

Much of the Rock Hill area has not seen an accumulating snow so far this winter.

Ahead of the front, temperatures are expected to climb to near 50 degrees Tuesday afternoon. With that milder air in place, precipitation from the disturbance could begin as rain. But it is expected to change quickly to snow, with colder air sweeping in.

Snowfall is expected to end by mid-morning Wednesday, followed by partial clearing in the afternoon. High temperatures will not climb out of the mid 30s, however.

And motorists could face another threat early Thursday.

“Increasing north-northwest winds behind the front on Wednesday will help dry surfaces during the day,” LaCorte says. “However, any residual water on roadways Wednesday night into Thursday, especially in shaded areas, will refreeze.”

The midweek disturbance appears to be the last wintry threat for a while.

Temperatures are forecast to begin warming Thursday and Friday, and afternoon highs will be in the 60s by the weekend. The long-range forecast shows above-average temperatures for the Southeast for at least the rest of January.