We are getting a classic Alberta clipper. I saw these all the time when I first discovered these maps. A clipper is mixed with cold on the north, and a Pacific plume on the south. It's the main type of cold air incursion for Toronto. The big cold blobs, or air glaciers, are an entirely new thing.
A big clairslide is now hitting Europe.
And it is showing as a big ball in the temp anomaly map.
Just in time for the Christmas covid-cold to hit.
ps. the weather people are on this, but I like doing mechanisms.
Lots of snow at the boundary between the tropical plume and the cold air that it is dragging. The key diagnostic is the diagonal trend.