Explosive cyclogenesis under a rip-roaring jet stream in the Pacific is about to bring extreme weather down the west coast of North America.

Nerd bit: I have contoured mean sea level pressure under the jet to show the text book interactions of the left-exit. Poetry in motion. pic.twitter.com/B1Gk2TR3K7

— Scott Duncan (@ScottDuncanWX) October 23, 2021