The spring speculation thread

[Summer8906]

Not sure if it's appropriate to put this in "Winter" discussion, so moderators feel free to move it, Can't find a suitable forum though.

With the models offering little or nothing in the way of either proper winter weather or an early taste of spring, maybe now is the time to distract ourselves by thinking about spring proper and what sort of weather we might have? Am thinking more of the first two thirds or so, up to say late April; May I think is too far ahead to talk of just yet.

Specifically, does anyone have any thoughts about spring this year? I'd guess that the strong jet stream in late winter this year is one thing to consider; also I have heard talk that a large polar vortex can tend to 'drop' in spring and we end up with a cold cyclonic type come April, but is this actually the case?

I'll start by considering years similar to now, i.e Februaries with strong and persistent zonality since 1989, and looking at what happened in the following early-mid spring. (I'm discounting 2011 due to the exceptional cold spell in December which might suggest the overall state of the atmosphere was significantly different that year). Obviously if anyone wants to add anything more scientific, please feel free to do so!

The strongest analogues are perhaps 1989, 1997 and 2000 as all those had anticyclonic Januaries. But I'm including all of them.

So in 1989, the zonality had always been present even in January but pressure was high to the south, meaning very mild but very dry. Around the 13th or so the jet dropped and the rest of February, and most of March until the 23rd, was zonal, dull, wet, and apart from the last weekend in February, mostly mild. After that, a brief warm anticyclonic interlude from March 24-April 2, then a cold cyclonic type through April with a mixture of northerlies, easterlies and Atlantic air.

In 1990 the outcome was rather different, the zonality had been going in January but at the end of February the jetstream migrated north, and March was very warm, dry, sunny and anticyclonic. April had varying types and varying temperatures, with the emphasis on dry and sunny (though Easter was wet and cold).

Next analogue was 1995 which also had the zonality in January (and Dec too, to some extent) though somewhat less mild than 1990. The outcome was different again with the wind swinging round to the NW in late Feb while the lows kept coming. Result was a cold and at times somewhat snowy interlude early in March with a NW type, before the rest of March became dry, fairly sunny and generally warm but with one or two brief cold interludes. April was again predominantly dry and sunny though with varying types and a post-Easter cold spell.

1997 was a strong analogue in the sense that most of January (after the 11th) had been anticyclonic with average temps, though obviously colder before that! It was another year that the jetstream migrated north at the end of Feb, and March was warm, sunny and dry - as indeed was April.

2000, perhaps an even stronger analogue (no significant early-winter cold) had a similar progression with northward movement of the jetstream in March, which was warm and sunny once again. However April was rather different, cyclonic and at first cold, with lowland snow in the south in the first week.

2007 produced another northerly migrating jetstream, with a warm and sunny March and April.

With 2014, there had been an extremely wet and cyclonic winter, the jetstream gradually started moving north around the 16th Feb which resulted in the second half of the month being less wet than the preceding two months. Another case of a dry warm sunny March following, though the last 10 days were more changeable. April was changeable but warm.

Then 2016, which was quite radically different to the rest, which a change to sustained cold-ish weather in March, an anticyclonic type dominating for much of the month followed by a cold cyclonic type late month. April was rather cool and changeable, with northerly types common.

Finally 2020, in which the zonality persisted to mid March then the rest of the month, and April, was sunny and mostly warm with occasional cold interludes.

So a bit of a mixed lot there, but the one frequent pattern is a change to warm, dry and sunny in March as the jetstream moves north. This was observed in 6.5 of the 9 years (0.5 awarded for 2020 as the change didn't occur until mid-March).

April, on the other hand, seems more variable with less of a clear pattern, though perhaps a slight tendency for warm and sunny. However the cold cyclonic weather which some have suggested in years with a strong vortex only occurred relatively infrequently (1989, 2000 and perhaps 2016). Perhaps two general types do manifest themselves fairly frequently though: warm and sunny, and by contrast, cold and changeable.

So hard to know where we stand on spring as a whole, but perhaps one could conclude that there is a fairly good chance of a warm sunny March. April could be very warm, or cold! Any other thoughts?

Edited February 10, 2022 by Summer8906

[damianslaw]

Hi Summer8906 I note you started a thread about Spring 2022 last week, but it has had no comments. I have just started a new thread about Spring 2022 prospects and perhaps you can combine your thoughts in that thread. Apologise for starting a new one but feel it somehow has become lost against all the stormy weather of late, and now Spring is just over a week away, perhaps people's attention may now start to turn more towards Spring. I'm certain if we weren't enduring such a volatile period right now, more people's attention would be on Spring.

[I remember Atlantic 252]

settling down with high pressure from 27th March, will be signs of it on GFS from around the middle 15th or so

April to be dominated by E'lys and northerlies, South wettest, NW driest

May, mostly E'lys and northerlies, many days colder than the average Jan/Feb SW'lys in the north

[Summer8906]

16 minutes ago, damianslaw said:

Hi Summer8906 I note you started a thread about Spring 2022 last week, but it has had no comments. I have just started a new thread about Spring 2022 prospects and perhaps you can combine your thoughts in that thread. Apologise for starting a new one but feel it somehow has become lost against all the stormy weather of late, and now Spring is just over a week away, perhaps people's attention may now start to turn more towards Spring. I'm certain if we weren't enduring such a volatile period right now, more people's attention would be on Spring.

Hi @damianslaw ok will do.