This next cold shot is different because the epo finally goes negative and injects some arctic air. Guidance continually tried to cool the N American profile at range and in defense that’s what historically SHOULD happen this time of year. Additionally even when the pattern in the pacific reverses and the coldest air shifts to N Amer it’s pathetic. Frankly the only place that seems to sustain truly arctic cold air masses lately regardless of the pattern is Siberia.