DISCUSSION: With everyone feeling the chill throughout the country it has been exceedingly difficult to find places that are experiencing seasonal temperatures. Recently California has experienced rainfall, snow in higher elevations, frost, and much cooler than average temperatures, which is no surprise as the rest of the country experiences colder temperatures, and an early start to winter.
Californians experienced a cold snap for overnight temperatures beginning Friday, December 16, seeing lows in the mid to upper 20's in and around the San Francisco Bay Area. These cooler than average temperatures lingered into the week making headaches for those traveling for the holidays. Temperatures are expected to rebound today as the previous high pressure system located off the coast of California had pumped cold air moved into the mainland. Some places can expect to see highs in the mid to upper 60's.
While locations such as Tahoe can expect snow for the holidays, Californians are crossing their fingers as rainfall is forecasted into Christmas Eve. With the presence of an upper level low churning to the southwest of Southern California, we should expect this precipitation to pull through downstream of the closed low as seen on the 500 mb map. Tonight for the Bay Area, lows will be much warmer and seasonal in the 30's and 40's. Current maps are showing the slight intrusion of a cold front located to the North, still not seen well on models but this will be the next area of concern for the Christmas Eve forecast. Coupled with the low outside of southwest California, moderate precipitation is expected with increased winds with snow possible in North Bay and Santa Lucia mountains. Between Thursday and Saturday totals between .5-1 inch with 2-4 in the mountains.
~Meteorologist Jessica Olsen