Data from Bloomberg shows that mentions of "polar vortex" in corporate media typically begin to surge in late December or the first half of January, signaling that the countdown has begun. 

On Wednesday, private weather forecaster BAMWX pushed out new weather models on X, showing confidence is growing for a polar vortex split to occur for the Lower 48. 

"The stage is set for Arctic outbreaks to round out December and kick start the new year!" BAMWX wrote on X.