Mammoth Mountain, CA today. photo: peter morning

NOAA has issued a Winter Weather Advisory for California from the northern boundary of Yosemite to into the Northern Sierra that is in effect from 8am – 11pm today.

3-8″ of snow is forecast to fall.

* SNOW ACCUMULATIONS...3 to 6 inches possible above 7000 feet with up to 8 inches 
over higher Sierra peaks. - NOAA Sacramento, CA

Mammoth Mountain, CA mid-mountain today at sunrise.

This is the first snowfall advisory and first snowfall of the season in California.

Snow has already been falling in Lake Tahoe & Mammoth, CA last night and this morning.

Half dome and Clouds Rest with snow in Yosemite National Park, CA today at sunrise.

3 California mountain passes were closed last night at 11:30pm due to snow:

9,945′ Tioga Pass (hwy 120)
9,624′ Sonora Pass (hwy 108)
8,736′ Ebbetts Pass (hwy 4)

Mt. Rose ski area with it’s first snow of the season in Lake Tahoe, NV today at sunrise.

Snow level will range from 6,000-7,000′ with this storm.

An unseasonably cool weather system will bring early season snow to the Northern 
Sierra today into early tonight. Snow levels are expected to range from 6000 to 
7000 feet with main snow accumulations above 7000 feet. There could be 3 to 6 
inches of snow along Interstate 80 above 7000 feet...impacting areas near 
Donner pass. Up to 8 inches is possible over higher peaks of the Sierra 
Nevada. Motorists traveling into these areas today and early tonight should 
be prepared for slick roads." - NOAA Sacramento, CA today

PURPLE = Winter Weather Advisory today. PIN = Squaw Peak at Squaw Valley, CA. image: noaa, today

Winter Weather Advisory for California:

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sacramento CA
404 AM PDT Thu Sep 21 2017

...Unseasonably Early Snow Over Northern Sierra Today into Early
Tonight...

.An unseasonably cool weather system will bring early season snow
to the Northern Sierra today into early tonight. Snow levels are
expected to range from 6000 to 7000 feet with main snow
accumulations above 7000 feet. There could be 3 to 6 inches of
snow along Interstate 80 above 7000 feet...impacting areas near
Donner pass. Up to 8 inches is possible over higher peaks of the
Sierra Nevada. Motorists traveling into these areas today and
early tonight should be prepared for slick roads.

West Slope Northern Sierra Nevada-
Including the city of Blue Canyon
404 AM PDT Thu Sep 21 2017

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM THIS MORNING TO
11 PM PDT THIS EVENING...

The National Weather Service in Sacramento has issued a Winter
Weather Advisory for early season snow, which is in effect from 8
AM PDT this morning to 11 PM PDT this evening.

* TIMING...From this morning into early tonight.

* MAIN IMPACT...Slick roads may bring spin-outs and longer travel
  times. Outdoor events and recreation may be impacted.

* LOCATIONS...Western Sierra Slopes, Interstate 80 impacting
  areas near Donner pass, Highway 50, high elevation campgrounds
  and trails.

* SNOW ACCUMULATIONS...3 to 6 inches possible above 7000 feet with
  up to 8 inches over higher Sierra peaks.