The Polar vortex is just as important as the storms coming in (IMHO) We know that the strat 'drives' weather via various mechanisms and so keeping tabs on it , and trop forecasts, so we can better gauge impacts on the ice.
Should we see a warming down to ground level then we could see a period of HP dominance over the ice and isn't knowing such might be on the horizon important?
Then there is WACCy and the PV disruption. Without the poorly formed , errant PV through early winter would we have seen the Polar Jet flinging storms into the basin?
I know we have separate threads but when it is a pertinent observation of atmospheric forcing then it belongs here as much as any other chart ( again IMHO).
It really does not look like a major warming is underway. The polar vortex is severely weakened but westerlies are not ready to surrender. And if the stratopheric polar night jet remains in place, wave guide and waves propagation and so on are not going to be modified :
https://twitter.com/splillo/status/821488732796755968The displacement will probably bring some blocking patterns in February, but I really doubt the AO will go down to basement or that strong high pressure areas will be back over Arctic. It really does not looks like a major event underway. The PV is severly disrupted but the wave flux is too much "eaquator-oriented" int the stratosphere, probably as a result of unending westerly QBO and strong Brewer Dobson circulation. And so the PV, even displaced, is not looking like it will break up and be torn apart.
http://img11.hostingpics.net/pics/777795GFSOPNH0036041.pngIl plie, mais ne rompt pas.
In my opinion, about the early disruption in the season of the PV, in the Automn, wich was quite exceptionnal. Of course, all weather phenomenon are related, and probably the early disruption of the PV was a factor during the winter. But the troposphere was, until now at least, only weakly coupled to stratosphere. The two jets this winter are seperated (subtropical and polar or thermal and eddy jet, as you want). The strong, well established subtropical jet is typical of La Niña. Associated to this, the polar jet was displaced far to the North probably due to some combinaisons of tropical forcings (strong convective activity in Indonesia and in Venezuela - Northern Amazonia associated with a weak La Niña probably sent energy to the polar jet), heavily disrupted baroclinic zone (early and strong siberian cooling and extensive snow cover associated with extremely low arctic sea ice) and yes perhaps the early disruption of the PV, but I really doubt it was a major factor. In itself, the tropospherics forcings are quite enough to explain the strongs and well seperated jets.
And for the early SFW, I also really doubt it will be the case. If the PV is not able to explode now, it don't see why it will be more likely to explode in March. Perhaps the QBO is going to help, but for now the QBO is lost.