Say It Ain't Snow: Winter Isn't Over Yet

(March 18) -- Spring fever gripped much of the nation this week, with generally mild, dry weather from coast to coast. The weather, however, is about to issue a reminder that the calendar says March, not May.

A major change to stormier, colder, and in some cases, downright wintry weather will take place during the next several days, starting in the Rockies and spreading to the East Coast by early next week.

The warm weather preceding the cold front will make the change even more dramatic, especially in areas from the Rockies to the Midwest, where snow will accompany the blast of cold air.

The heaviest of snow -- perhaps a foot in Denver -- will occur in the central Rockies from tonight through Friday. Significant snow -- several inches -- also will spread eastward through Kansas and Nebraska on Friday. Snow might even extend from northern Missouri to northern Illinois, including to Chicago, from Saturday into Sunday.

Temperature changes will be dramatic as spring quickly turns back into winter.

In Denver, where the high temperature hit 70 degrees on Wednesday, daytime temperatures on Friday, with a strong wind accompanying the heavy snow, will be in the upper 20s -- a greater than 40-degree drop.

Temperature drops of 25 to 35 degrees will be common through the Plains and Midwest as well, especially since the wind will make it feel even colder. Chicago's temperature will flirt with 70 degrees today but will fall into the 30s by Saturday evening and hold there on Sunday.

Spring cold fronts like this are notorious for producing dangerous thunderstorms and perhaps tornadoes; it's one of the great weather dangers of spring. Fortunately, it appears as if the air in advance of the front will be neither warm nor humid enough to result in numerous dangerous thunderstorms, but isolated dangerous storms will be a threat from eastern Texas through the Deep South from Friday night through Saturday night.

The cold front will lose a little of its punch as it shifts through the Mid-Atlantic region and the Northeast over the weekend. A batch of rain will precede the chillier air, and high temperatures will be in the 40s and lower 50s on Monday and Tuesday. Although this will not be as cold as areas farther to the west, the chilly days following a few days with sunshine and high temperatures in the 60s and lower 70s will be a noticeable change.

This cold shot may not be winter's last, either. Additional cold air from Canada will move southward during next week, certainly bringing cold weather to the northern Plains and upper Midwest.

It's unclear how far to the south the cold air will progress, but given the fickle nature of March, it's certainly a reminder that it's too early to proclaim that spring is here to stay, especially across the northern tier of the country.