Fig. 1-2: Forecast models indicate the most negative global atmospheric angular momentum regime of winter 2021-22 is ahead and responsible for an amplified ridge/trough pattern in the northern hemisphere including a split in the polar vortex.
Discussion: Into the middle third of March 2022, emergence of a late season arctic air mass evolves in central Canada stretching to the U.S. Great Plains. At the same time, another late season arctic air mass emerges in West-central Russia and extends to Southeast Europe. The late season cold outbreaks are caused by a slowdown in the upper-level wind patterns of the middle latitude northern hemisphere as identified by the forecast for the strongest negative phase of global atmospheric angular momentum of winter 2021-22. The polar vortex splits with most intense centers over northeast Canada and north-central Russia peaking in intensity in the 6-10-day period.