Heavy snow and gusts to about 65 km/h (40 mph) are forecast for the West Slope Northern Sierra Nevada and Western Plumas County/Lassen Park in California on Monday, November 17, 2025, with a Winter Weather Advisory in effect until 16:00 PST. A brief break is forecast for Tuesday and Wednesday, followed by increased chances for rain and snow showers on Thursday, November 20.
A developing upper-level low along the California coast is forecast to drift south toward northwestern Mexico by Wednesday, producing West Coast precipitation and heavy Sierra Nevada snow mainly on Monday, with showers and embedded thunderstorms over central California through early Tuesday and high-elevation snow extending into the Southwest through Wednesday morning.
For the West Slope Northern Sierra Nevada, the forecast calls for heavy rain and snow today, tapering to chances of rain/snow tonight, then partial clearing Tuesday into Wednesday before another disturbance brings rain and snow showers on Thursday, November 20.
Snow levels are around 2 000 m (6 500 feet) today, lowering to roughly 1 700 m (5 500 feet) tonight, then rising again Tuesday afternoon. Expected accumulations today are about 8 to 25 cm (3 to 9 inches) at higher elevations, with little to none at lower elevations; up to about 2.5 cm (1 inch) is possible tonight at higher elevations.
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A Winter Weather Advisory remains in effect for Western Plumas County/Lassen Park and the West Slope Northern Sierra Nevada until 16:00 PST Monday.
Look at that spin 🤩 This system has been a menace to deal with from a forecast standpoint. It’s not winter yet folks; it’s definitely still transition season. Let’s transition into discussing what to expect from this system in the thread below ⬇️🧵 (1/5) #nvwx#cawxpic.twitter.com/TV8avrboP3
Forecast totals are 15 to 30 cm (6 to 12 inches), with 30 to 60 cm (1 to 2 feet) possible on the highest peaks. South to southwest wind gusts may reach about 65 km/h (40 mph). Advisory guidance places snow levels generally near 2 000–2 100 m (6 500–7 000 feet) today, lowering to roughly 1 500–1 800 m (5 000–6 000 feet) by Monday morning.
Travel impacts are possible across higher passes during heavier snowfall and gusty winds; motorists should check Caltrans conditions and chain requirements before travel.
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A brief break with partly cloudy conditions is forecast Tuesday and Wednesday, followed by increased chances for rain and snow showers on Thursday with moderate additional accumulations possible, then a drier trend Friday into the weekend.
The National Weather Service has issued a Winter Storm Watch for the western slope of the northern Sierra Nevada above 5,000 feet and Yosemite National Park, above the Valley floor, from late tonight until Wednesday afternoon.
Heavy snow is forecast.
The snow levels will initially start out between 6,000 to 7,000 feet tonight, before lowering to 5,500 to 6,500 feet on Tuesday, and then down to 4,500 to 5,500 feet on Wednesday.
The heaviest snowfall is expected Tuesday afternoon and evening.
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Minor accumulations of up to two inches is possible down to 4500 feet. The total snow accumulations above the 7,000 foot elevation, will range from three inches to as much as two feet.
Southwest winds could gust as high as fifty to seventy-five mph along the highest peaks. Such strong winds could cause tree damage.
Travel could be very difficult to impossible. Persons should delay all travel if possible. Roads, and especially bridges and overpasses, will likely become slick and hazardous. Visibilities may drop below a quarter of a mile due to falling and blowing snow. If travel is absolutely necessary, drive with extreme caution and be prepared for sudden changes in visibility. Leave plenty of room between you and the motorist ahead of you, and allow extra time to reach your destination. Avoid sudden braking or acceleration, and be especially cautious on hills or when making turns. Make sure your car is winterized and in good working order.
Persons in the Watch Zone are urged to stay indoors until conditions improve. If you must go outside, dress in layers. Several layers of clothes will keep you warmer than a single heavy coat. Cover exposed skin to reduce your risk of frostbite or hypothermia. Gloves, a scarf, and a hat will keep you from losing your body heat.
Monitor the latest forecasts for updates on this situation.
