A developing storm system currently over the southwest is bringing an abrupt end to the spring-like weather weve been enjoying along the Front Range. Fog, snow, and severe storms are possible today as this system begins to impact the weather over Colorado tonight and through the day on Sunday.Areas of fog are possible this morning in northeastern Colorado until midday, and visibilities could be less than a quarter of a mile at times. Foggy conditions along the I-25 corridor south of Denver will continue clearing as the day progresses.Scattered showers and thunderstorms are possible this afternoon and evening along the Denver-Fort Collins urban corridor eastward throughout eastern Colorado. A few of these storms may become severe in the northeast, with large hail and damaging winds being the primary threats. Heavy rain is possible, and dangerous lightning is likely.Winter weather is the issue in the mountains this weekend. A Winter Storm Watch is in effect for the Front Range foothills and mountains overnight and through most of Sunday. Heavy snow is possible above 7,500 feet, with 6 inches to 14 inches of snow possible by Sunday evening. Winter driving conditions are likely, so Saturday is a good day to finish preparing your car for winter travel, especially if you will be traveling through Colorados mountains this weekend.Snow is possible along the Palmer Divide by Sunday evening for elevations above 6,500 feet, and light snow accumulations are possible.A Snow Advisory is in effect tonight through Sunday for the central mountains, from Steamboat Springs southward to Ouray and Telluride. Snow accumulations up to nearly a foot are possible.If you have plans to attend the Rockies game on Sunday night, or if you are running the Denver marathon, be prepared for cool, wet weather. Temperatures will be in the 40s on Sunday, and showers are likely in the morning and in the evening.Warmer and drier weather returns by the beginning of the work week.