Here is an example of what is known as a dry slot associated with large scale cyclones. This water vapor satellite image is from a storm in February.
As the upper level jet stream races overhead, we see heavy snow to the north of the jet and thunderstorms to the south of the jet. The dry slot, shown as the reddish region, cuts off the deep moisture, limiting the amount of precipitation.
We will try and nail down the details of this storm coming out of eastern Colorado tonight and Tuesday. Meanwhile, we watch and wait.