Our last big system was a disappointment because it was a snow-changing-to-rain scenario, and the rain washed away the little snow that we received.
Our next big system is likely to be a disappointment because it will be a rain-changing-to-snow scenario, and the temperature will drop below freezing about 3.2 microseconds after the precipitation leaves.
At least, that's what usually happens with these systems. To find a rain-changing-to-snow storm that really panned out, we might have to go all the way back to the Blizzard of '79.
Right now the amalgamation of the computer models shows that Cape Girardeau has a 30% chance of receiving at least two inches of snow:
The odds for 4+ inches of snow stands at 10%:
Of course, the probabilities increase to the northwest. An axis of heavy snow could develop somewhere around St. Louis, but there's a lot of uncertainty about that.
Warning: Geekery ahead
The big question is exactly when the cold air will arrive to change the rain to snow.
The Plume Viewer tool, which shows details of several computer model ensemble runs, is handy for visualizing tricky questions like this.
The plot below shows the projected temperature at three-hour intervals (in Zulu/Greenwich/UTC time) at Cape Girardeau. Each line represents a different model run, and the thick black line represents the average of them.
In a nutshell, most of the runs show the mercury plunging below freezing at 00Z 01-20, or 6 PM Saturday evening (circled in red). However, some runs are three hours earlier, while others are three or even six hours later.
Another question is the exact track of the low pressure system. Depending on how the storm evolves, we could find ourselves within a dry slot -- which means we'd get squat even if the temperature drops ahead of schedule. Or we could get an unexpected band of heavy snow right on top of us (I'm not holding my breath on that).
After a round of bitter cold and windy conditions, another storm system could bring rain or snow next week. If the past is any indication, the emphasis is likely to be on rain rather than snow.