Vast and long-lived blocking ridges over Alaska are something of a rarity. But that is exactly what all of the model forecast guidance is telling us will occur, in a process that begins around November 20. As warmth and stability ensue across the northwestern part of the continent, colder values above the Arctic Circle will be forced southward. Working with a marginal snow cover in Canada, the cA regime will spread to the line of least resistance, which is the subtropical jet stream now making for a miserable day in Texas and Louisiana.
With the edge of the colder readings making it far south, interaction with the southern branch shortwaves from the equatorial Pacific Basin may lead to a significant storm or two. I do not yet have agreement from the equations on the track and intensity scenario, just the suspicion that the disturbance may ultimately follow the Panhandle Hooker “B” path from West Texas into the Quebec Eastern Townships around November 22 – 25. Of course this would involve the Thanksgiving holiday and its travel period for many.
What follows, using climatology for Alaska 500MB blocks, would be a mostly cold pattern into the first week of December. This is a pattern that allows for another important storm. While I think next month will have an “up and down” character in terms of air mass displacement, best odds on precipitation coverage will be along the southern and eastern tier of the U.S.
Well, you wanted winter weather, right?