An extremely cold airmass has settled into NorCal and is continuing to dive southward. The upper low is currently dropping down the coast, and still has a couple of vorticity maxima associated with it that are producing scattered showers. As these isolated to scattered showers continue to spin around these vort maxes, some light snow will be possible from the Eureka area south to the San Francisco area, ending from north to south overnight. The best chance for some flurries in the Bay Area will be after midnight. This is by no means certain, but would expect at least a few isolated low-topped convective showers to be able to maintain themselves in the offshore waters and move inland overnight, most likely falling in the form of snow. Some more isolated showers w/ low (1000-2000 feet) snow levels are poss. in SoCal tomorrow. The bigger story, however, continues to be the extremely cold overnight lows that will be experienced across all of CA the next few nights. Of particular interest is the Bay Area, where lows could drop into the mid 10s in the colder valleys and will be in the low to mid 20s almost everywhere else. Even Downtown San Francisco will see subfreezing temps tomorrow night (30-31 F). Similar lows (17-25) will be experienced in the Central Valley and up north near Eureka. SoCal will be very cold in sheltered valleys, mountaintops, and even the coastal plains. Winds will be quite strong and gusty tomorrow and tomorrow night, esp. in the Valley, w/ gusts to 45 mph. This could actually create localized windchills below 10 degrees in populated areas in the late night and early morning hours. On the Bay Area peaks, such as Mt. Hamilton, windchills could drop below 0 F! Needless to say these will be the coldest temperatures experienced in CA in a number of years, possibly as cold as the December 1998 event. Frozen or burst pipes and crop damage could be a serious problem in some areas that are certainly not accustomed to such cold. Temps will  s l o w l y moderate over the weekend but will remain on the chilly side through next week. Will discuss the dismally dry long term in more detail this wknd.