Cold, snow to arrive in time for Thanksgiving.

A cold front moving into Northern California will bring freezing temperatures to some parts of the Bay Area this week and another round of snow to the Sierra just in time for Thanksgiving, forecasters said Saturday.

The cold, Arctic air is predicted to move into the Bay Area by Wednesday, when temperatures are expected to drop into the 40s and upper 30s in San Francisco, said Steve Anderson, a forecaster with the National Weather Service in Monterey.

Much of the Bay Area should see near- or below-freezing

temperatures Wednesday and Thursday mornings. Daytime temperatures are predicted to be in the low 50s.

Those making their Thanksgiving trips early in the week should see light rain showers Tuesday and Wednesday in the Bay Area as well, Anderson said.

Travelers heading to the Sierra should run into cold and snowy conditions. The northern Sierra probably will get

another batch of snow Tuesday — with the heaviest amounts coming in the afternoon — and into Wednesday, said Eric Kurth, a forecaster with the National Weather Service in Sacramento.

Snow should fall above 5,000 feet Tuesday before lower temperatures bring the snow level down to 2,500 feet by Tuesday night and below 2,000 feet by Wednesday morning, Kurth said.

The snow system, which could bring 4 to 8 inches by the end of Wednesday, will probably force drivers on Highway 50 and Interstate 80 to use chains by Tuesday.

Holiday travelers headed to the mountains should try to leave Monday rather than Tuesday, Kurth said.