Incredibly steady 0 C sst shift, even if it is about our Great Lakes
~Winter 2020-21 was unbelievably warm for North America
~None better example than the 0 C temperature Isotherm
CMC daily sea surface temperature chart shows also theoretically calculated 0 C line over land, it has been well North of the Great Lakes for months. In the recent past winters, this line was usually at the Great Lakes Latitude. This is yet another example of staggering warming due to a major circulation change, which maintained the center of Cold Temperature North Pole (CTNP) , on the Siberian side of the circumpolar world. Ellesmere frequently was the CTNP center of late, but only for a few day cycles, always bashed back warmer repeatedly by North Pacific in origin moist cyclones. As a result a good chunk of North America has has had a warm start of Spring:
NOAA 30 day surface temperature anomaly, the blue Siberia Alaska bit portrays the Central Eurasian dominance, tagged along with short time cold air buildup cycles formed in the North Ellesmere area, not captured on a monthly average, almost continuously sent to the Southwest, giving the brunt of High Arctic cold waves to the Western NWT. WD April 18, 2021...... Yearly projection is coming next, as you may guess, there is absolutely a warm Spring-Summer already set.