My understanding of SSWs is a bit like doing a reboot to fix a problem with software. Sometimes it fixes it, sometimes it does nothing. In essence, that is basically what they do - more or less a complete reset of the northern hemisphere pattern. Personally, I think people cling too much on the example of the January 2013 SSW and the very cold late winter and early spring that followed. .
Originally Posted by: Bolty
There's a list of major SSWs on Wikipedia, so it's easy enough to cross-reference - but bear in mind you'll have a different list of snowy winters to me, as living here in Kent we rely on Scandinavian Highs.
https://en.wikipedia.org/wiki/Sudden_stratospheric_warming In the first half of the 80s, they seemed to more often than not lead to a colder spell (with sleet or snow) anywhere from a week to 3 weeks later. In one case (1987), it seems to have happened immediately
after a cold spell - perhaps the blocking led to feedback which disrupted the vortex.
In the latter half of the 80s, nothing - and the same for the two (seems low) that happened in the 90s. In the 2000s? Not much at all from them. 2010 saw one after the cold spell in January (in the same was 1987 did), then we have 2013 and 2018, both of which led to a cold spell (and in 2018's case, a record-breakingly cold one). After that - nothing much.
All in all, a thoroughly mixed bag. I think the "roll the dice" analogy is a good one, and given the parlous state of the weather at the moment - I would grab that opportunity with both hands. I can't think of worse winter weather than gales, rain and exceptionally mild temperatures, so literally anything else would be better.
Note, however, that the above all refers to major SSWs, i.e. reversals at 60N. The modelling has only shown a mean reversal once (the ECM of a couple days back), with the most likely event just a displacement, or a minor warming.
(The terminology really needs to be looked at IMO, as a major SSW and a minor SSW are quite different events, despite both being called SSWs. A complete reversal could do with having a new name, I think!)