Winter 2021/2022 - General Discussion

Last winter was close to what I would like our average winter to be, maybe still slightly below par though because it was just a bit too Atlantic driven for my liking and not the exciting kind (there was hardly any storms) with the mild/wet period in mid-Dec and a very wet January with slow moving fronts up against blocking to the north but not enough cold air fed from the east. The February easterly was also a big disaster. The novelty of snow on New Year's Eve was cool even if it was barely a dusting, the severe frost on 9 January was interesting especially with no snow even though it was the coldest morning since December 2010 for most and the localised snowfall I had on 24 January that was mainly a northeast coastal Dublin affair. 6 December was a great day too with persistent freezing fog nearly all day.

Not counting our surface conditions, it was such an unusual season though with vast amounts of blocking in the Arctic Circle that wouldn't recede until the intensification of the stratospheric polar vortex through mid-February. The last time there was that amount of high latitude blocking for such a prolonged period of time was probably either winter 2009-10 or March 2013.

As for 2021-22, first thing I look out for is the North Atlantic sea surface temperatures come late November and see how they are doing. Right now, the North Atlantic is just in a very warm state in general which doesn't give much indication besides the onset of an active hurricane season perhaps in a month's time.

I'd imagine any leaves were to do with heat stress as opposed to cool weather. In the East at least we've had slightly above to very above normal temperatures since the end of May.

Leaves on the ground in Ireland in July aren't a sign of winter or autumn coming.

As someone who likes cold spells in winter last winter was better then the last 2 and better then many since 2010/11 but flattered to decieve especially the cold spell of February. The synoptics around Xmas looked good on paper but the air wasn't cold enough.

Perhaps last winter was some kind of attempt at a low solar minimum like winter like what we had a decade before. We are at the point in the current solar cycle of coming out of the minimum (as we were last winter) which can give cold winters so I'm hopeful this winter might be a step up from last winter.

Christ no, that winter 13/14 was just rotten storm after storm,hardly any frost etc

Another thing about that winter was despite the lack of cold,frost and snow etc it wasn't a particularly mild winter either. Max temps often in the 7c - 9c range,therefore the reason for example why the Highlands of Scotland got plenty of snow that winter.

Bit depressing to be thinking of winter already but anyways. I’ll just state for the record that before the autumn and the multitude of posters seeing more berries in trees than ever before, the hawthorn tree in my garden was complete white with blossoms this summer, as in you couldn’t see anything but white. So, I’ll expect a bumper crop of haw berries which has no way to predict with how harsh the winter will be.

Dunno what the winter will be like just yet, I’ll wait till end of August and I’ll have a better idea.

Ah Now........... Winter?..........

Although, I must check our heating oil.

Wet and mild.

Easterly QBO - increases the chances of a weak/meridional jet stream and sudden stratospheric warming events. The last time the QBO was easterly was way back in 2017-18. There was a second failure of the easterly QBO in 2020 only 4 years after the only other failure in the record in 2016.

Weak La Niña - La Niña favours -NAO more in the earlier part of the winter so the earlier part is likely to be colder than the second half.

Negative to neutral IOD - a strongly positive IOD was believed to have helped the rapid intensification of the stratospheric polar vortex in 2019-20 with little tropical wave activity to disturb it. So a negative to neutral IOD this time around should mean few impacts from it.

Warm North Atlantic - less conducive to explosive cyclogenesis in the North Atlantic and if a tripole forms can be more conducive to -NAO.

Weak jet stream during 2021 so far - the jet stream has been very meridional and weak during a lot of 2021 so far. This has been theorised to being down to low solar forcing.

Siberia has overall been colder this year so far as compared to 2020 when it was approaching record warmth so polar continental airmasses that advected eastward from here were unusually mild. It has been a similar story in the Arctic where it has been a cloudy summer so melting hasn't been as great as many recent years.

This well above average September could well be making the bed for the coming winter. We will have to lie in it. Not what I want. But the one positive is it would help with the heating bills.

Atm I reckon a mild and dry winter is most likely.

Well if it won't be mild and dry , mild and wet. One or the other. Either way mild imo.

Wouldn't be at all surprised if this winter will be one of the mildest on record.

Perfectly acceptable if there’s definitely not going to be proper cold and snow.

Perfect for me. Absolutely hate rain and wind. Absolutely hate rain with no wind. Absolutely hate wind with no rain. In winter, absolutely love dry with no wind. In winter, absolutely love dry weather. In winter, absolutely love no wind......you can see the pattern there!

No wind and dry weather means you can do outdoors stuff in a comfortable manner. Introduce wind into the equation and it becomes less pleasurable. Add rain into the mix and it is just yuck. Have both wind and rain and I have no urge at all for outdoor activities of any kind.

I took a look at the 'QBO' monthly index data for the period Sept-Dec and compared it with the Dec-Jan NAO index, and as far as I can see, there is little correlation to be had:

Orange line = NAO vs Blue line = QBO since for the years 1979 to 2021.

A run of negative QBO values in the last quart of the year does show a very, very slight bias towards a negative NAO but correlation is poor: 0.16 to be exact.

Of the top 5 most negative QBO Sept-Dec periods, only one (following) Dec/Jan period came in with a mean negative NAO value with the average NAO coming in at 0.9c.

Of the top 5 most positive QBO Sept-Dec periods, no following Dec/Jan period came in with a mean negative NAO value. Average NAO value stands at 1.7.

Yet, looking at this data in a different way. The top 5 lowest Dec/Jan NAO values have a mean Sept-Dec QBO value of -6.4 (3 out of 5 were negative), while the top 5 most positive mean NAO values for this Dec-Jan period came in with an average preceding QBO value of 1.01, but with 3 of the 5 of values being also negative.

I'll take a look at the Jan-Feb period later if I am in the mood to do so.

Edit: Data sources I used:

Thanks Syran.

I only used one measure though that didn't consider a 'lag effect' (if one exists) between the QBO and the NAO, though I thought, maybe wrongly, that a 4 month lag would be sufficient. That may be a wrong assumption though.

For what it is worth, I posted a video on the climate thread the other day that showed new findings regarding the stratospheric winds patterns etc and cold weather outbreaks which you might be interested in given that you know far about this phenomena that most.

How climate change is making winters colder - YouTube

Just something else to keep an eye on and consider this coming late autumn/winter season.

There have been three intervals of relatively cold weather so far in 2021, January into early February, April into May, and August. This makes me rather optimistic since the current warmth seems to be extending the general concept of a three to four month periodicity, and the next cold period should therefore be in the early winter. Early winter cold as we saw in 2010 (and 1981-82) is best because it can be more sustained and there\s less of a tendency for daytime temperatures to rise into snow melting ranges.

But not a prediction at this point, just an optimistic note that I hope to find more support for when I do the winter forecast in mid-October.

Nice informative post @hatrickpatrick. I am only getting to post now on the matters with university et al keeping me uber busy at the moment.

The idea of the Indian Ocean Dipole (IOD) was that in 2019 we had seen a strong positive phase through the autumn. This minimised atmospheric wave upwell from the troposphere to the stratosphere and in turn, the stratospheric polar vortex (SPV) was able to develop strongly with no disruption through the early winter period into the New Year of 2020. There was one minor warming event in late January that resulted in a slight deceleration of the zonal mean zonal winds but it was very minor and was not nearly enough to drive a change in the atmospheric pattern. The persistently strong SPV with little disruption throughout the season from December 2019 to even April 2020 interested stratospheric scientists in finding out what could have caused it. Zonality is normal of course but how stubborn the SPV was in a strong state was very remarkable. It was found that the IOD was the culprit in a study last winter but I had never heard about the IOD in affecting our weather before 2020. So the idea that the IOD will be neutral or slightly negative this autumn means it likely will not impact the winter patterns much as compared to 2019-20.

I will not open a stratosphere watch thread until November at earliest (although of course anyone is free to do so) as in my opinion, it is still too early for the stratosphere to mean much in the grand scheme of things and causing very blocked patterns. However, I see lots of people talking about the prospects of a major SSW (a reversal of the zonal mean zonal winds at 60°N 10 hPa) in late October which would be unprecedented as far as 10 hPa stratospheric records began in 1951 and thus it is extremely unlikely that such would occur and those models that showed such would have been outlier perturbations in an ensemble suite that shows a weak SPV. A major SSW in November meanwhile has happened before in 1958 and 1968 but the rarity of such with it occurring only twice in the 70 year record and last time being 53 years ago would make one hold a bit of skepticism as to the possibility of this happening in 2021. Canadian Warming events where the SPV is displaced towards Eurasia and a warming occurs over Canadian side of the pole in comparison are much more common in November and have occurred in many years but strangely has not happened since November 2000. These warming events are not strictly limited to 10 hPa and can occur in the lower stratosphere at times too such as 1962. Some of the recent modelling forecasts would be close to a technical Canadian Warming by late October, however the very latest ones have had a tendency to decrease the certainty of a dramatic weakening of the zonal mean zonal winds at 60°N 10 hPa and show the SPV recovering through November. This is nothing unusual and in fact lots of recent autumns have been characterised by fair amounts of blocking with October and November 2016 particularly standing out before the SPV recovered through the winter. Autumn 2017 had it, 2018 had it, 2019 had it with a trop-strat disconnection and 2020 had it too to an extent during October. So I'll wait and see developments through November before thinking about what the stratosphere will do or else I'll probably drive myself insane again with uncertainty!

Meanwhile, recent developments in the Pacific have shown the La Niña signature to become more central based which historically has led to overall +NAO winters including the Decembers which I have said before have an increased chance of observing a -NAO during a La Niña. Why this is the case is due to the MJO. An active MJO will increase the risk of blocking but a centrally based Niña is said to 'kill' tropical activity and in turn results in an inactive MJO. This is of similar mechanism to how the IOD impacts the SPV I outlined above with regards to atmospheric waves. It is too complicated for me to simplify so I won't get into anymore details than that.

P.s. I'm holding off on the 2010 comparisons! :-)

But we have frost most October's and will do at the end of next week too.

Oh you said it was Fakebook

A little more realistic:

According to that FB charts, we don't see frost here until early December on average, which is ridiculous but... it'd not surprise me if we didn't see any frost until then the way things are going this Autumn/Winter season. Ridiculously warm nights for the time of year.

It's ridiculously warm for the time of year:

We may be at that time of year where you would expect the seasons to be changing rapidly... it's just that they don't seem to be changing that much at all.