|600 mb temperatures closely represents the temperature of the entire troposphere. Courtesy NOAA. February 1982 (left) Arctic Atmosphere was extremely cold almost covering the entire Arctic|
while February 2014 (right) was substantially warmer, with a much weakened Arctic Ocean winter. Lame , more than twice smaller.
How can most presenters claim Arctic blasts lowering the temperatures enough in Eastern Mid North America to almost freeze the Great Lakes completely, when a really cold historical Arctic had less an effect on the same lakes? The answer is spatial compression and also a greater potential of heat radiation to space over the continents primarily because the continents cooled more readily as they are physically unchanged, opposed to a cloudy Arctic bombarded with Cyclonic intrusions having changed Sea ice wise.
The latest North American "Arctic blast" was influenced by a very small Archipelago cold air vortex, the Cold Temperature North Pole (in blue), which grew significantly in size and cooled further over Sub Arctic! It was not quite an Arctic blast. NOAA's satellite
missed some extent of the boreal forest area cooling in Mid-Quebec, radiosonde measurements there were in excess of -43 C at 600 mb. But the rest of the Arctic ocean 600 mb temperatures were more than 20 C warmer.
The also common saying "the Arctic Cold air" was replaced by advection from the South, "pushed away" by advection. Not quite so. Over the Archipelago, where the coldest air was during Feb 23-26, the air warmed from a trough of warm air extending itself from a Baffin Bay Low pressure along with and incursion of warmer air from the North! Originating from the North Atlantic no less. The Archipelago atmosphere primarily warmed literally from above both ways, from Latitude and altitude. The correct interpretation of the latest "blast": the remnant of coldest winter formed greater over the Boreal zone, it was a Boreal blast! WD March 6, 2014