A brief study of last winters pattern
Last year‘s La Niña winter produced below average snowfall for most of the country. The exception was the Pacific Northwest, specifically north of Oregon. There were two big systems that were about two weeks apart In the middle of this year’s 46.3 day cycle. I called them co-signature or CoSig storms because they were about equal in their production. They produced well in every cycle, with cycle 3, Feb 4th, being the biggest producer for CoSig 2 and cycle 4 March 14th for Co-Sig 1.
Below is the evolution of CoSig 1
CoSig 2
The second signature storm occurred a little less than two weeks after CoSig 1 each cycle. A quick note about the second storm, when it came through in February, the energy from this system dislodged the polar vortex and caused it to wobble. A week later it hit Texas.
You may have it backwards! “…A quick note about the second storm, when it came through in February, the energy from this system dislodged the polar vortex and caused it to wobble….”. It could very well be that a disruption to the Polar Vortex created the strong storms.
Have you started reading the blog I mentioned to you last year: https://www.aer.com/science-research/climate-weather/arctic-oscillation/, as Judah Cohen postulates a mechanism that could relate to the recurring patterns?
Also, I have been closely watching how the cold air from the North Pole is being dumped into the Bering Sea this late summer, and hope THAT pattern repeats this winter! Looking forward to your predictions for the coming season.
I have been following Judah Cohen, thank you for mentioning his blog. We have corresponded in regard to some pattern mechanisms and his insight has been helpful.
The polar vortex came after the deep trough and it is just my guess that was the cause of the wobble. That’s more of Dr. Cohen‘s expertise so I would defer to him for a better explanation, but when I watch an animation of the half-disc 500 mb with vorticity it appears to be connected.
The cold air dumping into the Bering Sea May be part of the evolving pattern. I have been watching how the systems have been moving through the Gulf of Alaska and they are definitely different than last year. There is that big warm blob of water, in the Gulf, which seemingly has changed the steering of the systems moving through the Aleutians. We’re going into another La Niña so it’s going to be interesting what changes will occur. Thanks for your comment!