An ice storm stretching across half the country could bring a mix of snow, ice and rain to Baltimore on Saturday.
Half an inch to an inch of snow, and anywhere from a few hundredths of an inch to a tenth of an inch of ice, are expected across Maryland, according to the National Weather Service.
With temperatures expected to hover around freezing, any warm air could limit accumulations, though.
"It's really borderline, with temperatures in that 31-to-33-degree range," said Mike Muccilli, a weather service meteorologist.
A winter weather advisory is in effect from 4 a.m. to 6 p.m. Saturday, with precipitation expected by daybreak and continuing through the afternoon.
Temperatures are forecast around the freezing mark close to the ground, but warmer air is expected to move in at higher levels in the atmosphere, causing the wintry mix of precipitation instead of just snow.
The State Highway Administration was pretreating roadways Friday with a brine solution that can prevent or delay formation of ice on pavement. The agency's administrator urged drivers to pay attention to conditions before venturing out.
"This system will have a greater impact on the metro area beginning as snow, but transitioning to sleet and freezing rain during the afternoon — and that will make driving treacherous," SHA Administrator Gregory C. Johnson said. "We strongly encourage motorists to wait and check travel conditions after sunset Saturday and make smart travel decisions."
School officials in Baltimore, Carroll and Anne Arundel counties canceled extracurricular activities and sports events scheduled for Saturday.
It is forecast to be the second icy Saturday in a row. Half an inch of snow fell Jan. 7, as measured at Baltimore-Washington International Thurgood Marshall Airport.
Ice and snow are forecast to fall across a wide swath of the country.
The weather service posted freezing rain advisories for the mountains of Western Maryland, Virginia and West Virginia, with as much as two-tenths of an inch of ice accumulation expected. Forecasters said winter weather advisories could be activated for more Maryland counties along the Pennsylvania border.
Ice storm warnings were in effect from northern Texas to Illinois, with as much as an inch of ice possible in some areas through Monday.
Several states activated emergency management procedures. In Oklahoma, Gov. Mary Fallin declared a disaster emergency. The state set up generators and supplies at temporary shelters in the northern part of the state. Missouri Gov. Eric Greitens and top cabinet officials manned an emergency operations center. Kansas officials were still waiting for the worst of it, with freezing rain in much of the state expected to arrive Saturday.
A driver was killed Friday morning when his SUV veered off of Interstate 55 south of St. Louis, a crash that appeared to be weather-related since freezing rain had caused the roadway to become icy. The Missouri highway patrol said two other people were hurt in weather-related wrecks.
The Associated Press contributed to this article.