Updated 12/12/10 8:08 p.m. C.T.

CHICAGO (CBS) — It’s shaping up to be a nasty weekend for weather in Chicago. First, the rain Saturday, then snow overnight. Now, frigid temperatures and high winds are in the forecast for Sunday.

A winter storm warning for all Illinois counties went into effect at 3 a.m. Sunday, and will last until midnight.

Rain fell Saturday afternoon, but cold air quickly spread across the region. Freezing drizzle and a mix of rain and snow fell overnight.

“It should transition to all snow by the morning,’’ NWS meteorologist Jim Allsopp said.

Chicago Streets and Sanitation Commissioner Tom Byrne said his team is prepared for whatever Mother Nature throws at them.

LISTEN: Chicago Streets and Sanitation Commissioner Tom Byrne

Strong, gusty winds are also predicted Sunday, the height of the nasty weather.

“The worst of it will be tomorrow during the day, with snow, strong gusty winds, blowing snow and wind chills below zero,’’ Allsopp said.

Two to four inches of snow are predicted for the Chicago area, but it could be much more for Indiana, especially in Porter County.

“In Northwest Indiana, there could be up to a foot of snow,” Allsopp said.

Winds will rapidly strengthen Sunday morning, with gusts in excess of 45 mph.

These winds, combined with the falling and newly fallen snow will create considerable blowing and drifting, with reduced visibility.

Temperatures will drop into the teens Sunday and brisk winds will persist, creating dangerous wind chills of 10 to 20 below zero on Sunday night through Tuesday morning.

The wind chills may reach as low as 30 below zero in some areas.

“If you have Christmas shopping to do, do it today,’’ Allsopp said. “You don’t want to be out there tomorrow.”