A brief window of calm weather activity will develop over parts of the far West on Thursday as the Pacific disturbances of the region trek eastward.As these disturbances exit, high pressure will nose into most of California, Nevada and Oregon with drier weather conditions. Chances of showers will persist along the Pacific Northwest coast and northern California coast as low pressure sets up offshore and the next frontal disturbance approaches these areas Thursday evening. In the western interior, a cold front will sag across northwestern Colorado and Utah through the day. The front will blanket the mountains of Utah and Colorado with snow showers and periods of heavy snowfall. Snow accumulations are expected to range from 8 to 18 inches by Friday morning. The highest accumulations are expected above 7,000 feet.Meanwhile, a nice warm-up is expected to the east of the Rockies as a large ridge of high pressure builds over the Mississippi River Valleys. Daytime highs are expected to climb into the 60s in the Upper Great Lakes and the 80s in parts of the Plains. In addition to warm temperatures, a cold front moving through the Upper Great Lakes will bring chances of showers and thunderstorms to Wisconsin and northern Illinois.Warm weather should reach the Eastern Seaboard by Friday.Temperatures in the Lower 48 states Wednesday ranged from a morning low of 17 degrees at Alamosa, Colo., to a high of 91 degrees at El Centro, Calif.———Online:Weather Underground: http://www.wunderground.comNational Weather Service: http://iwin.nws.noaa.govIntellicast: http://www.intellicast.com