Cosgrove on board it would seem. Cosgrove = @CAPE?
“With the instability of the various longer-term numerical models, I have to tread carefully here. If you follow the goings-on with the stratospheric vortex, splitting and reshuffling, the cold wave forecast to get entrenched in North America will be three to four weeks after the 10MB event. Which means I am about six days off from my original December 7-8 start phase time, but reasonably close to have some confidence in the prediction through the end of December and the first week of 2023. So on the idea that this winter weather event will verify (which means ignoring the operational GFS scheme form 18z and the latest CFS and ECMWF weeklies), it would be wise to focus on the two drivers to this pattern.
One is the prediction of a Hudson Bay vortex digging southward and phasing with the storm complex moving out of California and northern Mexico around December 19-20. The ensemble platforms, as a rule, endorse a three-way jet stream merger and seem to point out surface cyclogenesis near Galveston TX. That low pressure center would travel east, then north-northeast, along the U.S. shoreline in a manner typical of "Miller A" cyclones. Climatology would favor a conversion to frozen types in the south central U.S. away from the coast. But as more Arctic air gets entrained into low pressure moving up the coast (just prior to Christmas Day, though the timing is suspect), chances would increase for a substantial, if not heavy, snow event in Appalachia, the Lower Great Lakes and possibly the Eastern Seaboard. Following the snow threat would be substantial wind and perhaps three days of numbing cold from the High Plains to the Atlantic coastline.
There is also the matter of another disturbance arriving in the Golden State or Baja California in the hammock week between Christmas and New Year's Day. The extensive blocking signature following the Arctic Circle from Alaska to Greenland should hold through the first week of January, so there would be the chance for another round of snow and ice along and below 40 N Latitude just before 2022 makes its exit. I will hold on to my forecast of the January Thaw occurring roughly between the 10th and 22nd of next month. But if analog forecasts verify, major cold and frozen precipitation potential will cover the eastern two-thirds of North America from January 23 through February 28”
