December's damp, dreary days are likely to drag on right up to New Year's Eve.

December's damp, dreary days are likely to drag on right up to New Year's Eve.

Forecasters were expecting rain to continue through today and into Sunday, but slightly warmer temperatures should keep snow off the valley floor until late Sunday, said Dennis Gettman, a meteorologist at the National Weather Service office in Medford.

A snow advisory issued Friday afternoon called for as much as 4 to 8 inches of new snow in the Cascades and Siskiyous by 4 a.m. today. Snow levels were expected to rise to 4,000 feet Saturday with an additional 6 to 11 inches of snow during the day.

That could make for interesting driving conditions on Interstate 5 over the Siskiyous, where the pass lies at 4,310 feet, and Highway 140 over the Cascades, where the pass is just over 5,000 feet near Lake of the Woods.

Oregon Department of Transportation crews were preparing for adverse conditions with snowplows, sanding trucks, and plenty of de-icing liquid.

"We're ready to do whatever it takes to keep those roads open," said John Vial, ODOT's southwest Oregon regional manager. Vial said some crews have been working 12-hour shifts to keep roads passable.

ODOT spokesman Gary Leaming said motorists could face long delays getting over Siskiyou Summit if chain requirements are imposed.

ODOT can require all vehicles to put on chains, even those with four-wheel drive, in extreme conditions.

Gettman said freezing levels will likely fall low enough by late Sunday to bring some snow to the low-elevation passes on Interstate 5 north of Grants Pass.

Clear skies could continue as long as Wednesday, but temperatures will drop appreciably. Sunday's predicted high in Medford is just 28 degrees, and the overnight low could drop as low as 19 degrees. New Year's Eve will likely be clear and cold, too, with high temperatures in the 20s.

Rain and mountain snow could return as soon as next Thursday, he said.

For all the gray skies, total precipitation for the month has been relatively small. As of Thursday, just 2.42 inches of rain had fallen, .13 inches below Medford's average through the first 27 days of December.

Reach reporter Bill Kettler at 776-4492 or e-mail bkettler@mailtribune.com