ASPEN – A prolonged and potent winter storm could bring a foot or two of snow to the mountains around Aspen, starting Saturday night, according to the National Weather Service.

A winter storm warning is in effect for much of western Colorado from 6 p.m. Saturday to 6 a.m. on Tuesday, and below-normal temperatures on Sunday will turn frigid by Wednesday, according to the weather service.

The snow level will start at about 8,500 feet Saturday evening and drop to the lower valleys by Sunday night. South-facing slopes will see the greatest accumulation, according to the weather service, and the Colorado Avalanche Information Center has posted an avalanche watch for several mountain ranges, including the Elk Mountains surrounding Aspen.

The watch means dangerous avalanche conditions may develop. Large natural and human-triggered avalanches will be likely Sunday if the predicted snowfall materializes, the avalanche center said. Travel in avalanche terrain is not recommended.

An avalanche watch is also in effect for the San Juan Mountains, the Ruby Range and the Grand Mesa.

The forecast for Aspen calls for 1 to 2 inches of snow Saturday night, 2 to 4 inches on Sunday and 4 to 8 inches Sunday night. Snow and blowing snow remain in the forecast through Tuesday night, with overnight lows dropping into the single digits on Monday and Tuesday nights, according to the weather service.

On Wednesday, a high of 18 is forecast, with mostly cloudy skies and a chance of snow. An overnight low of around 3 below is expected Wednesday night.

The Thanksgiving Day forecast calls for mostly sunny skies with a high near 23.