Ah but it's cold outside indeed with Wednesday morning lows in the 20s in several areas, including 21 degrees reported in Petaluma, according to the National Weather Service.

Other low temperatures included 27 in Santa Rosa and Rohnert Park and 31 degrees in Geyserville and Sebastopol, according to local residents reporting to the weather agency.

"This past night was probably the coldest. It'll be chilly again tonight but not quite as cold," said Austin Cross, National Weather Service meteorologist.

Wednesday's clear and frosty weather was due to turn to rain starting by midnight.

Holiday shopping weather Thursday was slated to be very wet.

As much as four inches of rain could fall by Thursday night in the wettest areas, said Cross.

Santa Rosa was expected to get as much as two inches.

Thursday's storm will pack some strong winds, blowing 20 mph at times.

Snow wasn't part of the North Bay forecast, except perhaps a festive dusting on upper reaches.

Cross said the cloud cover should keep temperatures above freezing levels.

Friday's rainfall should be lighter than Thursday and showers were due to continue Saturday and taper off by Sunday.

Christmas Eve will include a slight chance of showers, according to current forecasts.

"It's looking to be dry by the 25th," said Cross.

Black ice was reported in some area early Wednesday, but the CHP reported no serious problems involving vehicles and ice.