[VIDEO] Chris Tomer’s Mountain Weather Update 11/18: Significant Atmospheric River Set to Dump up to 3 Feet of Snow on California

Denver-based meteorologist Chris Tomer is one of the most accurate forecasters we know. Check out and subscribe to his mountain weather forecast videos to see where North America will get the most snow.

“Storm system delivers light to moderate snow accumulation 11/18-11/19 in UT/WY/ID/MT/CO.
Then large trough of low pressure and major storm system with a moderate intensity atmospheric river (AR, Moderate) hits the West Coast 11/20-11/23 with feet of snow accumulation for the Sierra, Cascades, and high volcanoes. Interior Rockies will also benefit.

Snow Timeline:
Wasatch: 11/18(L), 11/23-11/25(H)
Tetons: 11/18(H), 11/21(L/M), 11/23(H), 11/26(L)
Colorado: Late 11/18-11/19(L/M), 11/24-11/25(H)
Tahoe: 11/18(L), 11/20-11/21(H), 11/22-11/23(H), 11/25(L)
Interior BC: 11/18(M), 11/20(L), 11/22-11/23(H), 11/26(H)”

– Chris Tomer

Brief highlights are below, but please watch the full video for the in-depth forecast, and while you’re there, subscribe and support the fantastic work that Chris Tomer does.

• Related: Brain Post: Atmospheric Rivers—Nature’s Moisture Conveyor Belt

Current Storm System

A Pacific Northwest storm system is pushing snow through Idaho and approaching the Tetons, Big Sky, Yellowstone, and the Wasatch range. Light snow is also transitioning into parts of Colorado.

• Wasatch Range: Expecting 1-4 inches of snowfall today through tomorrow morning.
• Tetons: Anticipating 3-8 inches, with higher amounts on the western side near Grand Targhee.
• Colorado: Light to moderate snow accumulations are expected between late today and tomorrow, especially in the central and northern mountain corridors. Generally, a 2-5 inch range is predicted.

Upcoming Atmospheric River Event

A significant weather event is forecast for the West Coast and interior mountain ranges:

• Timing: November 20-23, with effects lasting until around November 26.
• Intensity: Moderate intensity atmospheric river setup.
• Areas Affected: Cascades, Sierra Nevada, and interior Rockies.

Sierra Nevada:

• Mammoth: 1-2 feet of snow
• Tahoe: Up to 3 feet of snow
• Mt. Shasta: Potentially the biggest winner, with several feet of snow expected

Cascades and Pacific Northwest:

• Mt. Ashland: About 2 feet
• Oregon, Washington, and BC: 1-3 feet over high Cascades and volcanoes

Interior Mountains:

• Idaho: 1-2 feet
• Tetons: Significant snowfall expected
• Wasatch: Forecast uncertain, but potential for increased snowfall
• Colorado Western Slope: 1-2 feet, extending to the San Juan mountains

Extended Forecast

After the atmospheric river event, additional storm systems are expected to bring more moisture to the West, potentially lasting through November 27.

This weather pattern marks the first atmospheric river setup of the season, promising a significant boost to early-season snow conditions across many Western ski resorts.