Accumulating snow expected across Colorado; atmospheric river on the West Coast sending leftover moisture to Rockies

A tale of two forecasts is shaping up across Colorado this weekend. 

The next system approaches with an atmospheric river currently impacting California, sending some leftover moisture into Colorado. Accumulating snow begins across the high country early Saturday morning, with impacts increasing by Saturday evening along the I-70 corridor and during peak ski traffic.

Confidence is high in the mountains. Most locations in the high country should see 4 to 8 inches, with 6 to 12 inches common at higher elevations. Snow totals closer to 12 inches are likely near Vail Pass and the Eisenhower Tunnel, while the far northern mountains, including Rabbit Ears Pass, could see up to 18 inches by Sunday morning. 

Travel impacts are expected to be significant late Saturday night into early Sunday. Delays are likely, and overnight closures on Interstate 70 cannot be ruled out. If possible, delaying mountain travel until later Sunday morning is advised. Given how warm conditions have been recently, roads should improve relatively quickly once snowfall tapers off.

Forecast confidence decreases for the Front Range, including downtown Denver. The realistic range remains anywhere from a trace to 5 inches, but confidence is higher that snowfall will land somewhere in the middle of that range. Current projections call for 1 to 3 inches along the I-25 corridor, with up to 5 inches possible in the foothills.

The biggest challenge will be temperatures. Highs reach 59 degrees on Saturday, with snow arriving roughly 12 hours later. Much of the initial snowfall will be lost to melting, especially on roadways. While snow may fall for several hours overnight, one to two inches could melt on contact.

Expect a messy, slushy accumulation. Most roads should remain wet to slushy, with localized slick spots, especially on bridges, overpasses, and untreated surfaces.