Tulsa County and most of the metro area is included in the advisory until 9 p.m.
Early in the day, parts of the Tulsa metro saw drizzle which turned to freezing rain over the afternoon according to the News On 6 WARN Weather team.
Over the morning hours, precipitation moved into Southern Oklahoma. South of Tulsa, there was a 90 percent chance of wintry precipitation through midday, but the chances remained at 70 percent between noon and 4 p.m. for Tulsa and northward.
The western part of the state near Oklahoma City is experiencing travel issues, with weather-related wrecks on city streets and area highways, officials say.
News On 6 Meteorologist, Alan Crone said, any snow that might fall will be confined to northwestern Oklahoma and near the Kansas state line.
Thursday night ODOT said highways in central and eastern Oklahoma improved, but that drivers should still be alert to possible black ice.
ODOT said crews will continue to treat isolated slick spots as needed.
Additional precipitation is forecasted for early Friday morning, ODOT said, and it's crews will monitor the system as it approaches.
News On 6 Meteorologist, Dick Faurot said, "Right now, all indications suggest this will be a liquid event as surface temperatures are expected to be above freezing...however, the back side of the system still has the potential to produce some snow late in the day Saturday."
Faurot also said the system could bring up to as much of an inch of rain in some areas before we finally get some sunshine Sunday.
By 7 a.m. Thursday, the Oklahoma Highway Patrol reported that the Muskogee Turnpike north of Muskogee was slick.
Officials in Oklahoma City reported widespread wrecks on slick spots on city streets, although no severe injuries were reported. A semi crash closed down a portion of Interstate 35 earlier in the morning. The Oklahoma Department of Transportation sent an alert advising against travel in OKC unless it is necessary and asked drivers to take precautionary measures.
ODOT said travelers on the Turner Turnpike and Kilpatrick Turnpike could expect slick spots and were encouraged to be weather aware.
Crews were treating the Interstate 35 and Interstate 40 corridor and bridges in southern counties across the state all morning.