Medium-range forecasts are trending warmer across North America and especially the U.S. The catalyst to this warmer trend is a cold stratosphere over the polar region stretching south across Canada as indicated by the GFS in 5 days. As a review, the cooling and constricting stratosphere is compensated for by the warming troposphere below. Consequently, the upper-level pattern in the troposphere creating our weather is less able to produce cold air and arctic air generation is cutoff. Arctic air already present will retreat to deep snow cover.