The image above shows observed temperature readings (in Celsius) of the stratosphere and the troposphere for January through March of this year. However, because we are in January, that's all that has been filled in thus far. If you look at the colored portion of the image and see the encircled section, you will notice deep reds. This is the sudden stratospheric warming (SSW) phenomenon I have been discussing for days on end. When there is a SSW, warm air is forced into the stratosphere, weakening the semi-permanent Arctic polar vortex and permitting cold air to make a run at lower latitudes.
Usually, sudden stratospheric warmings will come and go, and their effects will come and go as well. Warm air pushed skywards will typically dissipate when the warming event has ceased. However, this time around, warming from recent SSW's is making its way downwards, filtering through the upper stratosphere down into the lower levels of the stratosphere. This, as previously mentioned, should coerce the polar vortex into at least a small degree of weakening; the extent of which is unknown at the moment.
If this warming filtration can persist, the polar vortex will continue to sustain very heavy damage, continuing to open the door wider for a colder back-end of winter in coming weeks.