Showers and snow in the mountains today, continuing through Wednesday. Widespread freezing temperatures Wednesday through Friday. Temperatures tend to warm up this weekend. Another round of unstable possible weather early next week.
Winter Weather Advisory until 10:00 p.m. PST tonight for Motherlode-Northeast Foothills/Sacramento Valley-Western Plumas County/Lassen Park.
winter storm Warning until 10:00 p.m. PST tonight for West Slope Northern Sierra Nevada.
Freeze Warning Wednesday 2:00 a.m. to Friday 9:00 a.m. PST for Carquinez Strait and Delta-Central Sacramento Valley-Mother Lode-Northeast Foothills/Sacramento Valley-North Sacramento Valley-North San Joaquin Valley-Valley south of Sacramento.
03:00 radar indicates that snow showers are currently continuing over the Sierra Nevada. We also received a few reports of light precipitation reaching some lower elevations. Temperatures are generally 10 degrees lower than yesterday, in the 30s and 40s in the valley and in the 30s and 20s in the mountains.
Some areas are also experiencing gusty winds with gusts of around 20-30 mph along the western edge of the Sacramento Valley, Delta and High Sierra. Locally stronger gusts were also reported over the Sierra Crete reaching over 100 mph late at night and early in the morning. HRRR and NAME Guidance from the high-resolution model indicates more widespread chances for snow and rain showers to develop this afternoon in northern California with the best chance over higher ground.
With the cold air mass in place, snow levels will be low enough that if showers develop in the foothills, some of this precip could fall as snow. Elevations above about 2,000 to 3,000 feet might see a few inches of snow.
The NBM WSUP viewer has about a 70 percent chance for Twain Harte’s Motherlode town at an elevation of about 3,500 feet to see at least 2 inches of snow by Wednesday morning and about a 90 percent chance for Arnold at an elevation about 4,000 ft.
There are also indications of the potential of showers convection associated with them. The best chance for showers of a more convective nature will be likely being just outside of our forecast region, in the Bay Area and south into the Central Valley. Although SPC included Sacramento Subway region and northern San Joaquin and Delta in their convection outlook.
The cold air left in the wake of the system starting mid-week will lead to sub-freezing temperatures early in the morning Wednesday through Friday. Some places could dip into the mid-20s in the valley, especially on Thursday when the coldest temperatures are expected. Lows can also approach daily record lows.
In-depth discussion (Saturday to Tuesday)
Higher level ridges are forming over NorCal on Saturday leading to a warming trend and dry weather. the Crete will move east on Sunday allowing short wave hollow approach. Sets do not agree with the strength of this wave and at the moment it seems that light precipitation will be possible mainly on the northern mountains. Higher level the ridge is building up on Monday with chances of precipitation retreating north.