Long-range forecasts for winter 2021-2022

I could see either of those working out and they aren't totally different outcomes by any means.

My own guess is maybe a bit closer to Pauldry than Danno above, but has elements of both included. I believe it will start out quite mild and perhaps relatively dry although with enough rain and wind at times to resemble a normal (recent) December into early January. There could be a colder spell from about mid-January to early February, but when this was the timing in 2012 the cold stayed largely to the east of Ireland. If it does expand enough to include Ireland then there could be one or two decent snowfalls. Then it seems likely to turn milder for much of February.

There seems to be potential for a severe winter in eastern North America and that often correlates with mild southwest flow patterns on this (or I should say your) side of the Atlantic. Even back in the era when cold winters were more frequent, this happened in years like 1875 and 1899. More recently it happened in 1934 and 2015 too. So there is perhaps some potential for this to turn out to be a mild to very mild winter with very little signs of cold, but being an optimist I will go for an outcome with at least some significant cold spells.

Well that did come at the end of a rather bland winter with a steady downturn in temperatures in late February, a three-day cold spell with lots of snow, and another brief cold spell about two weeks later with limited snow. Long-range forecasting is at a rather early stage of development and is more likely to catch overall trends than very specific events that may not have much persistence. A more spectacular change in the circulation that lasts for weeks, as in late 2010, might be somewhat easier to detect.

About that warm pool in the north Pacific, its influence is going to depend on the wave shaping -- if we get a shallow trough east of the Rockies and a lot of Pacific air flowing in, then cold shots will be very brief in the east, but it there's a larger amplitude wave pattern with the trough a bit further east than that, a lot of cold air can escape the arctic while milder Pacific air gets directed further north so that places like the Yukon and Northwest Territories get anomalous warmth. That's a fairly frequent La Nina outcome. The correlation with downstream weather for Europe is very weak as Oneiric3 noted.

Bumping this thread as there was a question relating to long-range forecasts in the main winter discussion thread. My own outlook has not changed much and I continue to be somewhat optimistic that we will see one decent wintry episode from blocking high pressure over central Europe or southern Scandinavia but question remains how strong the impact will be this far west. The dry November is overall a positive sign too. But there will probably be some mild or even very mild spells in the winter too, so it may be the case that one decent wintry spell and a few minor cold spells will be about the best we can get.

As we are getting closer to the actual winter season now, I hope to see a few other forecasts added to those already posted.

There was some talk about a winter forecast contest thread, but I think this thread should be enough of a vehicle for anyone who wants to post any specific ideas about the coming winter, it should be pretty evident from outcomes which forecasts are better or worse.

I feel optimistic that some interesting weather patterns lie ahead, this year has been rather variable in general with (by modern standards) a fairly good blend of warm and cold, so with no really strong signals of change, no reason to suppose this won't continue into the winter season ahead. Watch for high energy peaks to develop around the week before Christmas and a general downward trend in temperatures to follow.

It may still be largely a question of how far west blocking influences can extend.