apple tree not planted
Snow does not mean frozen soil. Even in St. Louis County, the ground should still be unfrozen. The simplest thing to do is to clear an area of snow over an annual bed or vegetable garden, then sink the pot into the ground. Then you can plant it in its proper location in the spring. But I'd do this now. Permanent snow cover is coming, as are very low temperatures, so you don't want to miss this window.
The alternative (much less reliable) is to winter protect the potted plant (using a heavy straw barrier around the pot) or to bring it into a warm-but-not-too-warm location (attached garage?).