Schools around Northwest Arkansas were announced that they were closing Thursday for the winter storm and many have already announced that they'll be closed Friday, including Bentonville and Springdale and Rogers.

Winter weather in Northwest Arkansas will continue through Thursday with a mix of sleet and snow with a mix of sleet, snow and freezing rain to the south, said Joe Sellers, meteorologist with the National Weather Service in Tulsa, Okla.

There should be a lull in the weather between 5 p.m. to 7 p.m. tonight with snow the rest of the night after that, Sellers said. The greatest accumulation of snow will be over night and the latest it would stop would be 2 p.m. Friday.

Road conditions had gotten worse over the course of the day today, according to officials at the Arkansas Highway and Transportation Department. Roads in Washington County were estimated 90 percent clear of snow and ice earlier today and were estimated to be 60 to 70 percent clear around 2:30 p.m., said Chad Adams, district engineer with District 4 of the Arkansas Highway and Transportation Department. Roads in Benton County were estimated 100 percent clear of snow and ice earlier today and were estimated to be 50 percent clear around 2:30 p.m., said Steve Lawrence, district engineer with District 9 of the Arkansas Highway and Transportation Department.

There haven't been many major traffic problems in Benton County, Lawrence said.

"It's better than what I was afraid it might be at this point," he said.

Crews with the Arkansas Highway and Transportation Department will be out all night to put salt and sand on the roads, according to department officials. It will become more difficult to treat the roads as temperatures drop tonight, Lawrence said. If temperatures drop close to zero degrees or below, the salt will no longer be effective in melting the ice, he said.

The Arkansas State Police has recorded 12 wrecks so far in Washington County and five in Benton County, said Lt. John Overman with Troop L of the Arkansas State Police. Troop L oversees Northwest Arkansas. Overman said not all accidents have been recorded yet, and he expected the number to rise throughout the night as temperatures drop.

A seven-vehicle wreck closed northbound lanes of Interstate 540 on Thursday afternoon near Porter Road, according to an alert from the Arkansas State Police.

County offices, courthouses, the Fayetteville Public Library and many other buildings were closing early because of the weather.

Ozark Regional Transit ceased services at 11 a.m. Thursday based on weather predictions and to make sure everyone stayed safe, Executive Director Joel Gardner said.

By 11:15 a.m., about two-thirds of the buses had returned to headquarters. Other buses were making sure passengers got back to their "place of origin" before weather became too serious, Gardner said.

"I have to get passengers home safely, and I also have to get drivers home safely," he said.

The transit will decide Friday whether and when to resume service.