Forecasting a winter storm is arguably the toughest call for a meteorologist. Will it be snow, sleet, freezing rain, or rain, or all of the above, and how much snow?

As a result, there's often a fine line between nailing a winter storm forecast and busting it. A perfect example of this was a storm in the Midwest about a month ago. In this sequence of satellite images (1) (2) (3) (4) (5) the storm is the blob of white moving northeastward through the middle of the country. The storm left behind a couple-hundred-mile wide swath of snow that stretches across Kansas, Nebraska, and Iowa. But notice how sharp the edges of the snowcover are.

In a close-up image a bit farther to the northeast, you'll see that while Chicago got snow, just to the south in places such as Champaign and Springfield, no snow accumulated. You can bet forecasters there used the phrase "near miss" a few times.