Stratospheric warming event? When/if the polar vortex splits over the North Pole has been a “hot topic” on Twitter/X over the past several days as medium/long range ensembles certainly predict such an event. This is a multi-week process that eventually — if the stars align properly — would set the stage for a major Arctic blast to drop across Canada into the Lower 48. The main problem, as we’ve discussed everyday, is the lack of cold air in the Arctic to dump into lower latitudes. However, there is an extreme cold pool forming over the ice sheet of Greenland that will invigorate/intensify cyclonic PV anomaly on the tropopause.

This is similar to the process that unfolded over the past 2-3 weeks over Eurasia. A strong surface high must form — and intensify over snow cover w/radiational cooling — as the thicknesses fall due to the warmer stratosphere above.