The prolonged (likely La Nina, low solar) induced warm, dry theme continues for UK, Ireland and Europe as well as much of the Northern Hemisphere over the last 12 months. Heavy rains have led to an unusually cool summer for parts of India and Pakistan and we’ve also seen much of Africa and southern hemisphere (albeit their winter) running below normal.

Year-to-date

500mb geopotential height anomaly 1 June-31 July, 2022

The warm July of 2021 was followed by a cool, wet blip in August followed by an incredibly warm September and autumn. The unusually warm September may well have been a strong enough indication of where winter was going but I admit I didn’t see it, possibly didn’t want to see it but winter 2021-22 was indeed a mild to warm one.

Indeed the warm winter was followed by a warm, dry summer 2022.

How about autumn 2022? Based on the persistency of warmth really extending back to the beginning of summer 2021 and the amount of heat sourced over the northern oceans, it’s hard to see it being anything other than warm.

Indeed the atmosphere ALWAYS throws in curve balls and surprises so although I feel warmth will prevail, there is always ‘in betweens’. In other words a warm overall autumn can have spells of cool or cold, wet and dry.

Current SST’s.

August 2022 temp anomaly

The problem is, calling warm may be a pretty safe bet BUT rainfall? Sure the La Nina is still present and looks likely to remain through at least the first half of the 2022-23 winter but seasonal shifts in the atmosphere could lead to different ocean-atmosphere feedback and while may produce one thing during one particular season, could produce the opposite in another.

My hunch is that while warmer-than-normal looks likely to continue through at least September, the natural cooling of the upper atmosphere and potential increase in ‘tropics to mid to high latitude interaction’ could lead to considerably wetter times ahead, likely LATER on into autumn, perhaps early winter (December).

Take a neutral to positive NAO in which Atlantic low pressure becomes more and more dominant for UK, Ireland and Western Europe mid and late September into October, the abnormally warm Atlantic, Med Sea could enhance rainfall ending the prolonged dry pattern and flipping it the other way. The atmosphere will always find a degree of balance, never exceeding it’s own limits. Prolonged dry spells almost always end with flooding and return to a much wetter pattern that can hold for some time.

Whether we see a major flip this autumn or winter or not, I strongly believe El Nino will make a return soon and when it does, heavy rainfall will become more typical than dry. This happened in 2012 which became one of the UK’s wettest summers following the prolonged dry spell of 2008-2011, caused by multi-year La Nina and low solar.

Could increase in solar activity influence our weather in the short term?

Hi Mark, 3 more M class flares departed the solar disk today, thanks for the shout out.
Xclass watch is now on. pic.twitter.com/l3yOGReJws

— David Birch (@Climate_Earth20) August 29, 2022

How’s September looking?

We start off September and autumn 2022 with a -AO/NAO signal, strong high pressure NORTH of the UK.

Based on latest run of CFSv2 weeklies.

WEEK 1. The high holds N of Scotland, trapping lows to the SW, S or SE and so focus of precip stays mainly south over France, Low Countries, England and Wales, except for fronts edging in from the WNW off the Atlantic into Scotland, Northern Ireland etc.

WEEK 2 looks to see the high shift west, reflective of the -NAO. With a lot of heat around, there may not be particularly chilly air associated with a trough that attempts to dive into Scandinavia or Russia initially at least but that ‘should’ change with time of course. Potentially more wet weather for southern UK, France, Low Countries, Germany, Alps.

WEEK 3: Ridge focuses over UK. Could be warm by day, cool by night. Dry theme overall! With trough further east, intrusions of cool likely into east Europe.

WEEK 4: Complete flip with trough over NE Atlantic, Ireland, UK… wetter period with systems pushing in off Atlantic.

Of course the further out you go the more unlikely the above solution becomes.

 

A -AO/NAO September is somewhat unusual as early autumn is more often dominated by a +NAO. Whether or not the negative holds remains to be seen.

IF the tropics do become more active with northward transfer of heat then we’re likely to enhance the pattern of either warm and dry or cool and wet.

I believe it’s a back and forth month. Warmer than average looks likely.

I will go for warmer and wetter than normal for Ireland and much of the UK with colder conditions affecting Scandinavia and Russia extending into southeast Europe in September.

Latest run of CFSv2 for September 2022.

500mb height anomaly

Precipitation anomaly

Temp anomaly

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