Fwiw, here's an animation of -5 thru +20 lag of this composite. Far from perfect, but I think it gets the overall idea right. Brief warm-up at small positive lag as -EPO/AK ridge retrogrades to Siberia, then a very favorable pattern for E US cold/snow shows up ~1-2 weeks later https://t.co/GlvwdeR34j pic.twitter.com/pMYvqo7zz6

— Eric Webb πŸ‡ΊπŸ‡¦ πŸ‡ΊπŸ‡Έ (@webberweather) December 14, 2021