Raleigh, N.C. — Sunny skies melted plenty of snow Wednesday, and that means commuters will probably need to look out for black ice again overnight, WRAL Chief Meteorologist Greg Fishel said.

Temperatures were staying low Wednesday. Highs reached the mid-30s in the afternoon.

Even though the sun's heat didn't warm the air much, its rays were melting plenty of snow.

"You might think we wouldn't melt a lot of snow, but that's not true," WRAL Meteorologist Elizabeth Gardner said Wednesday morning. "The sunshine is pretty powerful, even this time of year, enough so that we'll have a lot of melting."

That melted runoff will pose some dangers to drivers overnight as temperatures drop again into the 20s.

"Standing water will freeze resulting in black ice," Fishel said. The threat of black ice continues into the Thursday morning commute.

Some schools, businesses and churches continued to report delays, closings and cancellations due to the threat of dangerous road conditions. The delays include Durham and Wake public schools, which will start two-hours later on Thursday morning, officials announced.

"There is still potentially a lot of hazards out there," state Department of Transportation maintenance engineer Jason Holmes said Wednesday.

A winter weather advisory for central North Carolina warns of the potential for ice on roadways, bridges and walkways. The National Weather Service put the advisory in effect from 6 p.m. Wednesday through 9 a.m. Thursday.

Black ice forms when melting snow forms a thin layer of water on roadways. When the water freezes, the black asphalt shows through the ice, and it can be nearly impossible for drivers to spot in time to slow down.

Major interstates and roadways and some secondary roads were clear Wednesday, Holmes said. And improved road conditions earlier in the day could create a false sense of security to evening drivers.

"To me it’s even more dangerous because people get comfortable, the road is clear and then all of a sudden they pop up on black ice," Holmes said.

The state DOT treated as many roads as possible during the day and plan to monitor road conditions closely overnight. Throughout the past two days, the state DOT has used 3,000 tons of salt, half the amount in storage, on roads. Most of the salt was placed as the snow fell. More salt has been ordered to replace the amount used.

However, later Thursday, we'll see "a substantial warm-up," Fishel said.

A high-pressure system will also drift farther to the east, allowing warmer winds to blow in the from southwest – finally making the mercury rise. Thursday will likely see a high around 48 degrees.

"Friday, our temperatures could be 5 to 10 degrees above normal – almost a heat wave coming in," Gardner said.

Temperatures will break the 50-degree mark on Friday and Saturday. And the highs will likely stay within a degree or two of the normal highs and lows through the start of next week.