Here's why. The low pressure system that will turn into our winter storm is over the Gulf of Alaska (pink circle showing storm at 15,000 feet). While there is useful weather satellite coverage, there are no weather balloons and few aircraft sampling the atmosphere. So, the computer models have a difficult time when there is low confidence in their analysis of the current state of the atmosphere.
The storm now over the Gulf of California is forecast by the models to move over far northern Mexico Sunday night. Snow is likely in El Paso (while it is raining in Toronto)! A second storm should get close enough to the first (i.e., within 1,500 miles) that it will "kick" the first storm northeast (purple arrow). If so, there will be a major snow storm in the Plains.
So, here is the likelihood of 6" or more of snow Saturday afternoon through Monday.
AccuWeather forecast for specific amount for your location.