GEFS has begun suggesting a transition to the Alaskan Ridge regime may occur in the middle third of January. Of the 4 North American regimes, days assigned to the Alaskan Ridge have the highest risk of severe cold for most of N America. One to watch! https://t.co/ExQKUsKNXC pic.twitter.com/CAxAl5nnXY

— Dr Simon Lee (@SimonLeeWx) December 27, 2021