The ECMWF and GFS models are pointing towards a snowstorm for the Northern Plains, including the Denver, CO region. The GFS projects a strong low coming north from the Colorado area and producing snowy conditions for the Dakotas. That blue line is the rain-snow line: anything north will be snow, anything south will be rain, theoretically. The 0z ECMWF takes it to another level, bringing not one, but TWO strong low pressure systems along for the ride. Now, in some aspects, this would mean twice the snow. That is not necessarily true. However, the prospect of 2 lows does indeed increase snow potentials. Below is a snowfall 3 hour accumulation map from the ECMWF. Credit to Wundermap.
Check out how strong the line will be for North Dakota between rain and snow. Accumulations may go as high as 6 inches (of higher), but that remains to be seen. Stay tuned with The Weather Centre, your winter weather service provider, as we track this system across the model boards.