~There were Cyclonic incursions in the past , but there was more sea ice thickness
~Density Weighted Temperatures of the Northern Hemisphere undeniably demonstrate a warmed planet especially since 1998
~There is no sun over the Arctic yet we witness no "IRIS" effect when the planet is at its warmest
First we look back to late 1980 when the multi-year ice was very thick:
It was a warm Christmas over Siberia in 1980, much warmer than over the Canadian Arctic.
600 mb temperatures courtesy NOAA are very close to the Density Weighted Temperature (DWT) of the entire troposphere. Temperature picture December 26 (left) was not much different compared to December 29 (right), The Polar region in total darkness coldest air morphed a bit but everywhere temperatures of the entire atmosphere was colder than -20 C while in the Canadian Arctic as cold as -40 C almost all the way to the North Pole. DWT 's clearly show the center of the Polar vortex, where all Northern Hemisphere circulation driving winds turn counterclockwise around it.
El-Nino 1998 was strongest, likely stronger than 2015 to date, already we see the circulation pattern markedly different same December 26-29 comparison with 1980. Note the beginning of a Cyclone affecting the DW Temperature profile of the atmosphere about Iceland on December 29.
In 1998 the sea ice started to decline in thickness and extent. Its a marking year. Winter was still
strong during the holiday season. Day to day variations of DWT's were very reasonably predictable and not dramatic.
El-Nino 2015 is similar to 1998, except for a larger warmer sea temperature anomalies for the North Pacific. Yet December 26-29 DWT image is staggeringly different, as well as sea ice thickness and extent:
but rapid decrease in sea ice thickness since 1998 has had a major playing role decreasing the build up to winter.
From December 26 to 29 2015, the entire Arctic atmosphere significantly warmed in total darkness! An important Low pressure system, one following many, easily penetrated the North Pole region which had DWT temperatures usually close to -40 C, now more like -8 C, again this is the temperature of the entire atmosphere not just the surface, in the past not changing fast in a matter of days. In total -no sun - darkness the usual pattern was stable DWT's. Another marked feature of current 2015-16 season is this darkness warming, never readily noticeable in the past, as winter progresses it usually gets colder not warmer! Now we noticed with ease warming bursts at least 3 times since November 2015. The Cold Temperature North Pole (CTNP) and Arctic has warmed significantly since 1998. This allows Cyclones to penetrate a weakened state of winter which is made in great part in the Arctic, this affects weather world wide. But now, this is new, we witness temperature warming surges causing incredible dynamic changes undoubtedly which will continue to cause tremendously different weather scenarios, some good for warm temperature lovers, but will cause many severe stressful events for human infrastructures as much as on all ecosystems.WD January 2, 2015