Fig. 1: IMME global SSTA forecast for January 2022.
Discussion: Inevitable is the likelihood of the feared polar vortex pattern in January 2022. Why? Simply stated, there is precedent for persistent high-amplitude high-pressure ridge areas forming over large regions of much warmer than normal SSTA during the past 10 years in the winter season. Implied by the International Multi-Model Ensemble (IMME) are high-amplitude high-pressure ridge areas across very warm regions of SSTA just east of the Dateline and across western and central North Atlantic (Fig. 1). In-between the two ridge areas, the atmosphere (always looking for balance) compensates by allowing a cold upper trough (polar vortex) to form over central North America. How strong this feature will be or how far south this feature drift is a question mark. The most recent NCEP CFS V2 has the polar vortex on the Minnesota/Canada state line (Fig. 2). ECMWF is farther west with the January polar vortex (Fig. 3). The inevitable polar vortex pattern means plenty of snow cover, cold air mass source region and ability to deliver the cold into the U.S. Snow cover will dictate how cold the U.S. can be and the air mass trajectory determines who is hit hardest. Be prepared for at least one cold air outbreak during mid-winter!
Fig. 2-3: NCEP CFS V2 and ECMWF depiction of the January 2022 polar vortex pattern across North America.