Saturday morning looks to easily be the coldest night so far this fall/winter season. A frigid Canadian air mass will be moving southward in the wake of deep upper trough (see map).
Clear skies and diminishing winds, along with very dry air, will make for this big chill. Lows will range from 15 in the normal cold spots to lower 20s most locations.
Temperatures are expected to moderate as southerly winds return Sunday, but clouds will cause it to remain on the cool side of average for early December (average is highs mid 50s, lows mid/upper 30s).
Another shot of chilly air lurks in the models for about Wednesday. It seems this active and cold early winter pattern will continue for a while.