Welcome to my 13th annual UK, Europe summer forecast. As always, when compiling this forecast for the upcoming June-August period there are multiple factors which have been taken into consideration. They include the past winter pattern, type of spring just observed as well as other factors including current ENSO state, global and regional sea surface temperature anomaly, current solar state and the recent eruption of the Shiveluch volcano in Far East Russia.

Glance back to Summer 2022

June-August 2022 highlights

June temp anomaly

Summer hit early and hard courtesy of Africa. For a 7-day stretch, somewhere in Spain reached or exceeded 40C with a max of 44.5C at Andajur (only 0.7C off the national June record) and it’s said to have been the country’s earliest ‘intense heat in over 20 years’.

France observed it’s earliest 40C day, hottest June day and one of it’s hottest of all-time with Pissos recording a national maximum of 43.4C.

While it could be considered ‘hot’ with a UK peak reading of 32.7C at Santon Downham, Suffolk, the UK largely escaped the heat due to the presence of deep low pressure positioned N of Scotland which produced unseasonably strong winds of over 50 mph near sea level, 85 mph above 4,000ft in the north and west and held temperatures below average even into NW England. This low drove a cold front south, quickly driving continental air back out as fast as it arrived.

The immediate day after the near 33C spike, temperatures over the Midlands were a full 15C lower and even struggling to get above 10-11C mid-afternoon at the same time Paris was in the high-30s! A contrast rarely observed.

July temp anomaly

July was a bookend month featuring cool opening and end but with a blistering ‘short lived’ surge of heat in between which set new records in England, Scotland, Wales and UK overall.

Even Ireland’s Phoenix Park in Dublin hit 33.0C.

HIGHEST TEMPERATURES FOR JULY 2022

47.0C Portugal **NEW JULY RECORD & 0.4C OFF ALL-TIME RECORD SET IN 2003**

46.0C Spain

43.4C France

40.3C England/UK **NEW ALL-TIME RECORD**

What fueled the record heat across much of Western and Central Europe was the months of extremely dry conditions. The first 6 months of the year was England’s driest since 1976.

August temp anomaly

Last summer was one of the hottest on record for Europe.

Drivers at play in 2023

Developing El Nino

Following the 3-year La Nina, we are back in an official NEUTRAL ENSO state (El Nino-Southern Oscillation) but more or less ALL long range computer models point to the development of an El Nino this summer with some models suggesting a strong Nino event by as early as August but more likely moderate to strong later into next autumn.

Whether the ‘still developing’ El Nino has influence over the next 3-months remains to be seen.

Record warm Atlantic & Global SST’s

While El Nino conditions can have a warming influence on UK and Europe temperature, it can also have a wetter influence too.

The Atlantic is very warm and the overall global ocean surface is believed to be at it’s warmest levels on record, this you would assume would increase the chances of a ‘warmer-than-average’ summer across much of the Northern hemisphere. However, it is much more complex than that of course.

While the Atlantic Multi-decadal oscillation (AMO) remains firmly positive (warm), the Pacific Decadal Oscillation (PDO) is negative (cold) despite a warming of the eastern equatorial Pacific and therefore this can mix things up with regard to the upper pattern.

CFSv2 SST forecast for Jun-Aug 2023

I believe the much warmer than average waters extending from the Azores towards the UK could increase summer rainfall IF we have a low to the W or SW. Air circulating around LP could sweep over this warm ocean surface and increase moisture within the atmosphere and therefore increase precipitation.

As the below tweet shows, El Ninos can bring both types of summer to Europe…

https://twitter.com/WorldClimateSvc/status/1656727279555280899

Wet spring (UK, Ireland, central Europe)

It’s been a relatively cool and wet spring for much of Europe with drier Scandinavia and Iberia. For the UK and Ireland it’s been near average temperature-wise and wetter than average. This is thanks in part to the lag effects of the mid-Feb Sudden Stratospheric Warming (SSW) as well as the Madden Julian Oscillation (MJO) which helped enhance a negative Arctic and North Atlantic Oscillation (-AO/NAO) with dominant blocking between Greenland-Iceland and Scandinavia which in turn has forced a southward displacement of the storm track (jet stream).

The result of wetter soils (could), not only increase humidity in which some of the sun’s incoming energy would have to go into evaporation rather than heating (slightly cooler surface to air temperature as a result) and or may help enhance lower pressure which increase chances for precipitation (also resulting in a cooler temperature) with the help of warmer-than-normal surrounding SST’s.

Dry ground breeds heat, hence with the extreme drought over Iberia, we saw Spain record it’s hottest April day on record of 38.8C. Incidentally, a wetter pattern now is helping ease the heat and drought situation.

This spring’s rains has potential for a VERY different outcome this summer for many parts of particularly central and southern Europe compared to last year when many central European rivers partly dried up.

According to some sources, Italy is experiencing it’s wettest May in 70 years.

500mb geopotential anomaly 1 March through 14 May

Eruption of the Shiveluch volcano (Russia)

A major eruption of the Shiveluch volcano in Russia’s Far East Kamchatka peninsula occurred April 11, 2023. While eruptions are not unusual in this region (part of the Pacific Ring of Fire), the intensity was, about the strongest in at least the last 30 years. It’s said to have released an ash cloud above the 54,000ft level and possibly higher.

What may be important about this is the fact this volcano is located pretty far north and with release of ash potentially well into the stratosphere relatively close to the Arctic, there’s an outside possibility that this may have weather and climate implications over the next few months and beyond. While there’s no way to prove that this volcano will or could affect the upcoming summer pattern, I believe it’s plausible that it could perhaps aid a possible cooling effect and increase chances of seeing more rain.

Strengthening solar cycle 25

In terms of the current solar cycle (25), we are likely 12-18 months away from the maximum or first of two peaks. The strengthening of the current solar cycle would certainly point to a potential warming influence but that being said, according to several sources, the global SST anomaly is at it’s warmest on record and each month which goes by appears to see earth’s atmosphere within the top 5 ‘warmest on record’. So, whether the solar cycle is at a minimum or maximum, warmth continues to rule these days.

In terms of where we’re at with the current cycle, we appear to be on par with the period 2012-2014 in terms of activity. Interestingly the current solar cycle appears to correlate nicely with the last time we came out of a multi-year La Nina and observed the onset of an El Nino.

Perhaps a striking difference now compared to the past 10 to 20 years is the warmer overall backdrop compared which favours warmer than average but all things aren’t equal so there are exceptions to that rule.

Increasing power from the current cycle suggests warmer but could equally increase rainfall, aided by warm SST’s and El Nino developing.

The Prediction

Based on all of the above and considering the likely WARMING influence from solar cycle 25 approaching a maximum, developing El Nino and warmer ocean surface, I will firstly suggest that a WARMER-THAN-AVERAGE summer 2023 is likely for most of the continent including the UK and Ireland!

JUNE

As for rainfall, I believe it’s going to be quite a mixed summer with likely lower pressure across the south and through the Mediterranean basin during June with above average heights at both 500mb as well as the surface across more northern parts of Europe including Scotland and Scandinavia, possibly extending south to include England and Wales. This would point to a warm, dry June for much of the UK, Ireland and northern Europe, average to below average temperature and above average rainfall across Iberia and much of the central and western Med, possibly including the Alpine countries and Balkans.

I do suspect the presence of low pressure near to the Bay of Biscay with possible influence reaching southern Ireland, England and Wales could increase potential for heavy rain/thunderstorm activity which could greatly temper heat and increase ‘localised flood threat’.

Meanwhile Scotland, Northern Ireland and possibly Scandinavia as well as Germany and Poland observed warm to very warm days or 27C+ Scotland, 30C+ Sweden, Finland, 32C+ Germany, Poland.

TEMPERATURE: Above average, esp Scotland RAINFALL: Slightly wetter than average, esp England/Wales.

UK maximum: 28-30C (Scottish borders, Greater London)

CFSv2 for June

JULY

I believe July could see somewhat of a reversal in the upper air setup with lowering heights over or just north or west of the UK, this could encourage warmer sourced air northwards from Africa and Iberia bringing 1 or 2 visits of 30C+ days to particularly the south and east UK.

Scotland is beneath or close to the influence of low pressure, more rain and cooler temperatures. Quite the opposite to what June may offer.

Stronger low pressure influence is possible at times which could bring below average days and wet weather to much of the UK and Ireland. Unusually cool days and nights like seen back in 2015 is a possibility and days like 2012 is also possible which was very wet of course.

We could see a bit of back and forth in the upper setup across the continent with spells of low as well as high pressure with typical hot conditions over the Med and southern/central Europe

TEMPERATURE: Near average overall, possibly cool for Scotland RAINFALL: Wetter than average, esp Scotland.

UK maximum: 31-33C (Greater London, Kent, E Anglia)

CFSv2 for July

 

AUGUST

August could become the warmest month for Europe, particularly south and east with heatwave conditions developing. Meanwhile low pressure could be dominant in the means close or over the UK as the possible influence of the El Nino with feedback off the warm surrounding SST’s. Warm waters could enhance rainfall potential.

Low pressure in the means however DOESN’T mean warmth cannot pay a visit and with possible hot conditions over Iberia or near continent, means we should see a couple of brief plumes of heat lifting north and edging in off the near continent but overall, I think low pressure wins the battle.

I think for NW Europe, August is slightly below average and wet, more so for Northern Ireland and Scotland, possibly NW England and Wales. Slightly warmer, less wet in the south and east of England, closest to the continent.

Depending upon the MJO, we also must consider an increase in tropical activity which may enhance a wet pattern for W/NW Europe.

El Ninos tend to decrease tropical cyclone development and activity within the deep tropics BUT with abnormally warm waters further north, we could see systems form and strengthen outwith the traditional MDR or Main Development Region…

Remember the abnormally warm SST’s may help tropical cyclones maintain strength and a warm core for longer than usual and closer to Europe than you would typically expect.

The tropics however can also boost high pressure patterns too so one needs to be cautious regarding recurving tropical systems over the N Atlantic.

UK maximum 29-31C (Greater London, Cambridgeshire)

CFSv2 for August

Of course these long range models will vary day by day following this publication.

THE JUNE TO AUGUST 2023 VERDICT

A SLIGHTLY WARMER & WETTER THAN AVERAGE SUMMER IS EXPECTED FOR THE UK AND IRELAND…

Tags: featured, long range, summer forecast 2023