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Very Cold Storm to Bring Rare Snow to Low Elevations in California

Feb 23, 2011; 2:30 PM ET

A very cold storm now in the Northwest looks still on track to bring California, and other areas, a rare taste of the white stuff other parts of the nation take for granted. This storm could be a once-in-20-or-30-years storm for parts of California for how cold it will be and how low accumulating snow will get. By Friday in the north and late Friday night and Saturday night in the south, it will be almost as cold as it can be. It is rare to see 500 mb temperatures dropping to around 35 below zero C around the Bay Area and 32 below zero C near Los Angeles. 850 mb temperatures will fall to a ridiculous 8 below zero in the north to 4 or 5 below zero in the south. This will be a no-frills update. I will give detailed forecast by region with text only.

Sierra:

Snow developing from north to south Thursday and Thursday night with gusty winds and heavy snow for about a 12-hour time period. Additional snow likely Friday into Saturday into Saturday evening but more showery in nature while still being locally heavy at times. Accumulations above 6,000 feet: 18 to 36 inches with blowing and drifting. Snow levels will drop to the lower foothills from north to south Friday and Friday night, and 6 to 12 inches is likely above 3,000 feet with locally higher amounts; 3-8 inches can fall down to 2,000 feet and a few inches are possible down to 500- to 1,000-foot level. Snow will end Saturday night but it will remain very cold through Sunday with snowcovered and icy roads likely to remain well beyond the ending time of snow.

Bay Area to Sacramento Valley:

Rain and snow will develop in the afternoon and evening Thursday from north to south and continue Thursday night. Snow levels will start at around 2,500 feet but by Friday will drop down to 1,000 and at times can drop down to at least 500 feet Friday afternoon and night. Snowflakes may be seen at even lower elevations. A few showers could linger Saturday, especially over southern sections of this region. Snow accumulations above 2,500 feet will be 7 to 14 inches with 3 to 6 inches down to 1,500 feet and a coating of snow possible down to 500 feet. It is entirely possible that in a heavy shower of snow could fall down to sea level. Travel in this area, especially above 1,500-2,000 feet, will be on snowcovered, icy roads. After the storm, very cold air will remain with near-record cold temperatures Sunday morning ranging from the low to mid-20s interior valleys to the low to mid-30s at the coast.

Central Coast to Central Valley:

Rain and snow will develop from north to south Thursday night and continue Friday. Between 1/2 and 1 inch of rain will fall. Snow level will be around 3,000 feet Thursday night but will drop to 1,500 to 2,000 feet by Friday evening. Coastal passes will have rain and snow with some pass tops having mostly snow. Showers and in places a thunderstorm are likely Friday night and Saturday. Snow levels fall farther, down to 500-1,000 feet by Saturday. Snowfall above 2,000 feet will be 4 to 8 inches, and a few inches can accumulate down to 1,000 to 1,500 feet. Snow could be seen in any heavy shower much lower than that. Precipitation will end Saturday evening and night but it will stay very cold through Sunday night with a hard freeze likely in the valleys Sunday night.

Southern California:

A little rain could break out as early as Friday afternoon, especially from the Los Angeles Basin on north, but the most rain will fall Friday night, then become showery Saturday into early Saturday night with a couple of thunderstorms possible as well. Snow levels initially will be around 3,000 to 3,500 feet Friday night, locally lower interior mountains. Snow levels will fall late Friday night and Saturday, bottoming out at between 1,000 and 1,500 feet, but dropping as low as 500 feet in a heavy shower Saturday afternoon and evening. Rainfall amounts of 1/2 to 1 inch seem likely but can be highly variable due to the showery nature of things Saturday. All snow is expected to fall at all the passes, The Grapevine, the 14 and Cajon Pass with 6 to 12 inches likely Friday night into Saturday morning. Additional snow will fall during the rest of Saturday and Saturday evening, but amounts will be quite variable. Roads will become snowcovered and icy with temperatures well below freezing. Travel on these roads may become impossible due to snow and ice on the road. Prepare for the worst if you are expected to travel. Accumulations at 2,000 feet could range from a few inches to over 6 inches in the south and west facing mountains. A coating of snow could accompany any heavy shower down to 500-1,000 feet around Los Angeles and 1,000 feet in the San Diego area. Snow is likely to accumulate in all Upper Desert locations with more snow likely in the Antelope Valley and elevations above 2,500 feet in the eastern Upper Deserts than other areas. However, anywhere along the I-15 could have snow and road conditions, especially around the passes, could become quite bad. Think back to that Sunday after New Year's Day when travel took 10 to 15 hours from Vegas to L.A. Temperatures will be very cold Saturday, low 50s along the coast, low 40s in the coldest valleys. Sunday night could bring freezing temperatures to the colder valleys.

Elsewhere:

I believe some snow will fall in Las Vegas, especially Saturday afternoon and early Saturday night. The greatest precipitation in Arizona comes Saturday afternoon into Sunday morning. This could be a 10- to 20-inch snowfall for Flagstaff and other mountains and snow here too could fall pretty low before it's all said and done, perhaps down to 2,000 feet Saturday night. I will have more on this later.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com