This may help explain why forecasting snow is extremely challenging. If you are a weather enthusiast, you probably already know that if the storm changes path even by 15 or 20 miles, it can make all the difference in the world with regards to where the heaviest accumulation will setup.
Here is an example heading into this first big snow event of the winter season. One forecast model shown on the left , known as the NAM (North American Model), shows the heaviest snow staying south of Hwy 54 (click for larger image). The other, GFS (Global Forecast Systems) shows the higher amounts in central and eastern Kansas. So how do we make our prediction? We try to understand which model is doing the best job at the current time and base our forecast off of it and we have a few other models to try and help us figure out what's going to take place. We have other sets of data we can look at too, but I always tell people that figuring out snow accumulation is probably the hardest task we do as meteorologists. What's the second hardest? Probably swallowing a bad forecast... but fortunately we don't have too many of those. =)
Have a great weekend and be safe.