The first winter storm of the season arrives in the Bay Area tonight.
The heaviest rain falls in the North Bay from 10 PM to 4 AM Monday morning. I expect up to 0.25" of rain at the valley floors with snow mixing in as the event ends. A dusting to a couple of inches of snow will accumulate on higher peaks above 1000 feet.
We have a cold rain for you morning commute elsewhere around the Bay. The greatest amount of rain, 0.25 to 0.50 inches, falls between 4 and 10 AM. Snow levels will drop to near 1500 feet during this time with 3 to 6 inches of snow possible on the Diablo Range and Santa Cruz Mountains. Snow will mix with rain at lower elevations, no accumulation.
The biggest question mark is the cold air's arrival time. Everywhere around the Bay the cold air moves in as the moisture moves out. Snow levels will reach their lowest elevation after the moisture moves away.
With a clearing sky Monday night and the coldest air over us as the sunsets, frost is possible with a killing freeze in our valleys. A FREEZE WATCH is in effect Monday night through Tuesday Morning.
It is Snowing in Lytle Creek, Ca.
Started about 4:30 PM
Posted by: Adolph | January 20, 2010 at 07:43 PM