Night Shift 6z GFS. 7 Day GIF: 500mb height anomaly. Uhhh.... Okay. Quite a change this run. The ridge develops further offshore, and if it were stronger we could have gone right into a chilly air mass quickly, with possibly a backdoor cold shot. That little cutoff low knifing through the ridge messes things up. It was kind of close though.... Hmmm....
Day 6 (4-run trend) 500mb Height Anomaly, 850mb Temps. This really shows the potential. Note that arctic air is much closer to this run into British Columbia and Alberta. We just needed a stronger ridge.