A winter storm watch is in effect for Denver and much of the Eastern Plains from Wednesday afternoon through late Wednesday night, the National Weather Service said.
Six to 8 inches is possible east of Interstate 25 from south Denver to the Palmer Divide, forecasters warned.
Parts of the high country could pick up as much as a foot of snow from the slow-moving Pacific storm, the National Weather Service in Grand Junction warned.
Farther east, the watch becomes a warning for parts of Colorado near the Kansas border, with more snow and higher winds expected.
Denver has a 30 percent chance of rain after about 11 a.m. Wednesday and a 70 percent chance of snow Wednesday night. The high is expected to top out at 38 degrees.
The city could pick up another half inch Thursday, when the high temperature is forecast to reach only 30 degrees. Temperatures are expected to warm into the more seasonal 40s Friday and Saturday, before another chance of snow and temperatures in the 30s Sunday.
The storm will leave several inches of fresh snow on most locations in Western Colorado from Wednesday morning to Thursday afternoon, as the state's snowpack continues to lag.
Steamboat Springs, Vail, Aspen and Telluride have snow chances from Wednesday to Sunday.
The statewide snowpack Tuesday was 71 percent of its 30-year average. The Colorado River basin was 65 percents, northwest Colorado was at 74 percent and southwest Colorado was at 83 percent of average.