09/02/2024, 6:37 am EDT
As early September arrives, most striking, is the cool weather set-up in the Midwest/East U.S. centered on the 6-10/8-12-day period. At that time, both the arctic oscillation (AO) and North Atlantic oscillation (NAO) shift to negative phase supporting a high latitude blocking ridge and amplified polar vortex centered on Ontario and the Great Lakes.