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Wanted to rewind to see key synoptic elements responsible for the Central US cold air outbreak.
Ridge building over Alaska & SE Canada dislodged a TPV complex into S Canada, where it persisted more than a week as the air mass grew colder before it was diverted S the Central US.
Ridge building over Alaska & SE Canada dislodged a TPV complex into S Canada, where it persisted more than a week as the air mass grew colder before it was diverted S the Central US.
The middle step, where tropopause polar vortices (TPVs) hang out in S Canada is crucial, allowing additional arctic air to pool up against the Rockies w/ little modification as it slowly sagged south.
End result: A remarkably high magnitude & long duration cold air outbreak.
End result: A remarkably high magnitude & long duration cold air outbreak.
No doubt an important part of this process was the widespread upper-latitude blocking (aka strong -AO) over N Canada that kept the TPVs equatorward cyclonically rotating in place.
Stu had a great visual of that a few days ago w/ a merger of two TPVs. https://twitter.com/StuOstro/status/1360274970371366917?s=20
Stu had a great visual of that a few days ago w/ a merger of two TPVs. https://twitter.com/StuOstro/status/1360274970371366917?s=20
