Gezien GEM/ GFS met blokkades rond het punt met de laagste waarden op 10 hPa. Technisch gezien weliswaar geen SSW, maar wel een impuls. Die -volgens Domeisen- tot downwelling moet leiden.
Het hoeft niet meteen een effect van de minor warming te zijn maar kan ook teruggevoerd worden op eerdere stratosferische impulsen, te weten de Canadian Warmings van december. In die geest schrijft ook Judah Cohen in zijn blog van deze week.
In fact, if you look at Figure 11 long enough, you can convince yourself that the predicted warm/positive PCHs in the lower troposphere and negative AO (see Figure 1) in early January are a result of downward propagation or influence from the upper stratosphere that was a result of the first Canadian warming and the timing is consistent with the rule of thumb two week delay. But all of this, I feel complicates what predicting what will be the impacts not just one but multiple PV disruptions. This situation reminds me of the SSW back in 2021 where it also was unusually complicated. Of course, the fact that I know to identify more different behaviors of the PV could add complexity not because the PV is doing anything unusual, just I didn’t know to recognize it previously and now I do.
https://www.aer.com/science-research/climate-weather/arctic-oscillation/