A National Weather Service graphic posted Thursday afternoon projects snow levels in Southern Oregon and Northern California on Saturday ranging from zero inches in Medford to more than a foot near Crater Lake.

The heaviest snow in a spat of overdue winter weather expected this weekend will fall early Saturday, forecasters say, but lower elevations won’t see falling flakes until late Saturday night through Sunday afternoon.

Those in elevations above 2,500 feet in Southern Oregon and Northern California best buckle on their snow boots from 4 a.m. to 10 p.m. Saturday, say the National Weather Service prognosticators in its Medford office, while lighter snow may drift down to the 1,500-foot elevation Sunday morning.

A winter storm warning has been issued from 4 a.m. to 10 p.m. Saturday in the Cascade and Siskiyou mountains. Accumulations of 6 to 12 inches of snow with winds gusting to 40 mph are expected, making driving conditions hazardous. While travel is “strongly discouraged,” according to the NWS, those who must venture over mountain passes are encouraged to carry tire chains, a flashlight, blankets, food, water, medication and a fully charged phone.

Ashland’s forecast calls for calm before the storm, with sunny skies Friday, rain Saturday (possibly mixed with snow), and a chance of snow Sunday morning. The chance of snow continues Sunday night and into Monday morning. Rain is likely Monday night, Tuesday and Wednesday.

Ashland’s severe weather shelter will be open Friday, Saturday and Sunday nights. Doors open at 5 p.m. and the shelter closes at 9 a.m. the next morning. For more, see the Ashland.news calendar at ashland.news/events/, or go to the city of Ashland notice by clicking here.