Will 2024 have the new hottest day on record for the uk?

[raz.org.rain]

 Summerlover2006 generally there's no strong correlation with ENSO states and summers in northwestern Europe, it's somewhat contentious. ENSO effects are more pronounced during winter in this part of the world.

[WYorksWeather]

 Don It unfortunately does seem quite likely. Unless we get a very notable warm spell to dry out the ground beforehand, and especially if we continue a tendency for our warmer spells to be more south-westerly than southerly to south-easterly, then I could easily imagine multiple spells of high 20s or low 30s with pretty high humidity being possible.

Anecdotally I was leaving work one day last June, and I distinctly remember 27C on my weather app, but with a feels-like of 32C.

 B87 I for one think and hope you're wrong! Not too long until we find out...

[BlueSkies_do_I_see]

What would the  July CET look like if we had a continuation of Spring 2024-like pattern of humid, cloudy mild nights with minimums consistently in the mid to high teens, with above average precipitation limiting the highs to temps in the mid 20s C at best? Could we get a record CET of 19.9C without hitting 30C the whole month?

This is not the weather I am looking for, just a theoretical question. What was the closest CET July  month to this?

Edited May 3 by BlueSkies_do_I_see

[Scuba steve]

Personally I see a protracted period of dry ish weather possibly out to  the beginning of July though not overly hot  possibly  increased thunderstorm activity   In August increased solar activity possibly the cause ? and an early autumn from the start of September ,I have 95% confidence in this

[B87]

 BlueSkies_do_I_see July with average days, warm nights, dull and very wet could be 2017 or 2021.

Mean temps of 19.4c and 19.6c respectively.

[WYorksWeather]

 BlueSkies_do_I_see I think it'd be very unlikely to get close to record territory limiting maxima to mid-20s. Almost every day would have to be reaching 24-26C to produce a record-challenging July or August under those parameters, with minima around 15C. That is a very high minimum - especially given the recording up to 9am which allows for temperatures falling in the early hours. In fact it has never happened in any month - highest monthly CET minima is 14.0C in July 2006 and August 1997.

I do think it might be possible if you extend the parameter to 30C. That way you could formulate a semi-realistic set of daily means. You could have two thirds of the month average something like max 28C min 14C (mean of 21C) and then say ten cooler days with max 23C and min 13C (cloudy, wet and humid, mean of 18C). That would give an overall mean for the month of 20.0C. Obviously exact numbers can be adjusted but that seems like it could be possible. Prolonged CET readings above 15C are very unlikely, hence why you need the higher daytime temperatures so they're not needed.

That still means though that somewhere outside the CET region in a favoured spot would probably surpass 30C in practice. I imagine a month similar to that outlined above would have an absolute max around 32C somewhere in the SE, but we wouldn't have any CET days with maxima over 30C. But the entire month not reaching 30C is probably pretty unlikely if it's going to be a record breaker or near-record month.

[Don]

 WYorksWeather In that case I'm not going to enjoy summer one bit!  That hot and humid week we had in August 2020 was dreadful and the worst I've ever known.  I was relieved the weather turned unsettled and cool during the second half of the month!

[WYorksWeather]

 Don I think the key will really be the wind direction. The absolute worst wind direction for the combination of heat and humidity would be a consistent SSW wind direction, coming in from the Mediterranean coastal areas, with heat sometimes turbocharged by more direct southerlies. An ordinary westerly would be just a classic washout, and if we get pure continental flows they'll generally be pretty dry I'd imagine with a higher temperature ceiling but lower humidity.

Anyway, we will soon find out. I'm already noting some positive feels-like temperature differentials on weather apps for next week (inaccurate though they are) with e.g. 20C feels like 21C. Not uncomfortable of course at that kind of level, but if we see relatively high humidity with temperatures in the high 20s and low 30s it will feel very uncomfortable.

Probably the worst period for that would be mid July to mid August - after that the lengthening nights tend to inhibit very high minima, and before mid July the SSTs are probably not high enough (though this year, with a record warm North Atlantic, we could even see serious heat and humidity combos in June).

 

[raz.org.rain]

16 hours ago, WYorksWeather said:

I think the key will really be the wind direction. The absolute worst wind direction for the combination of heat and humidity would be a consistent SSW wind direction, coming in from the Mediterranean coastal areas, with heat sometimes turbocharged by more direct southerlies. An ordinary westerly would be just a classic washout, and if we get pure continental flows they'll generally be pretty dry I'd imagine with a higher temperature ceiling but lower humidity

James Peacock discussed this a few weeks ago too, it's looking like the lower North Atlantic could be a major source of humid heat this summer.

 

[Ben Sainsbury]

 Weather Enthusiast91 Just catching up with this thread but personally, it is absolutely possible that we could break the UK hottest day on record this year. Will it happen... pretty unlikely. 

The funny thing about 2022 is that conditions weren't actually "perfect". Sure, all the conditions were top tier but not perfect. The peak of the 850hPa temps actually arrived during the overnight hours, the previous night. The period of extraordinary high temps only actually extended a few days too, if we were talking longer then we could definitely have seen higher than 40.3C. 

Nowadays, soil moisture seems to fluctuate very quickly. It only takes a few days of warm temps and dry conditions to really get rid of the soil moisture. All it would take is for a very warm, dry two-week period and we'd be in the position to break the record again assuming all other conditions fell into place.

Personally, I feel like under "perfect" conditions we could hit 41C, maybe even 42C.

This year, I don't see us hitting 40C but I think we'll only fall a few degrees short.

[WYorksWeather]

 raz.org.rain I was talking about this in the model thread last night - some warm SSTs around the UK and to our south-west building over the next 15 days, days 0, 5, 10 and 15 below (charts are much the same from ECM 00z as they were from last night's 12z:

 

 

[Don]

6 hours ago, Ben Sainsbury said:

Personally, I feel like under "perfect" conditions we could hit 41C, maybe even 42C.

If I remember correctly, there were some forecasts going for possible max's of 42C in July 2022, but as you say the peak of the 850hPa arrived at the 'wrong time'?

[Don]

 WYorksWeather Hmm, not looking great really, but what will be will be! 

Edited May 4 by Don

[Metwatch]

Short answer: Highly unlikely, less than 0.5% chance.

[ANYWEATHER]

We are now entering a phase of colder weather , the eruption of Hunga  tonga  ,has not been realised. Southern Europe this year will get one if not the coldest summer on record, and the UK will be lucky, to get 30c, although the caveat of some of the most intense thunderstorms in decades.........interesting times...☺

[WYorksWeather]

 ANYWEATHER I'd be willing to go with the following for this year with very high confidence:

• This year will be the warmest or second warmest on record globally, and minimum of top 5 for Europe.
• Less than 1% of the Earth's total land area will record a coldest on record year (so allowing maybe one or two countries only).
• Closer to home it will be at minimum a top 10 CET year, and top 5 in the shorter UK record.
• The UK's annual maximum will be at least 32C.

Looking slightly further ahead, and also with very high confidence:

• The overall global temperature for 2021-2030 will make it the warmest decade on record.
• The 5 year period 2026-2030 will be warmer than 2021-2025, despite the transition to La Nina and unwinding of any Hunga Tonga effect.
• Before the end of the decade, there will be at least one more temperature recording of 38C or higher in the UK.

With more moderate confidence, closer to 50-50, I would also add the following by 2030:

• Somewhere in Europe will officially record 50C for the first time.
• The UK record of 40.3C from 2022 will be beaten again.

Theoretically if you're right all of those would be highly unlikely. I'm more than willing to be quoted on any of these - feel free to bookmark my post. I will also try to bookmark it and revisit at minimum the predictions for this year (of course no one knows what they'll be doing at the end of the decade!).

 

[WYorksWeather]

 Metwatch I'd be interested to know why you'd go that low - not saying you're wrong necessarily! Is it that you think the Coningsby event was very exceptional, on the order of a 1 in 200 chance at the moment in any given year, or do you think it's higher than that in any random year, but that circumstances this year don't favour it?

Totally not a criticism, but always interested to hear alternative views. I do agree with the broader point of course that you certainly wouldn't bet on it happening in any given year, though.

[ANYWEATHER]

 WYorksWeather okay , will bookmark my thoughts against yours and see later the results! Goodnight.

[lassie23]

 Scuba steve I think it will reach 44 degrees on the 4 of July because of the sun's flares

[manutdmatt1986]

The early building of warmth across south west Europe and cold anomaly out in the Atlantic make me think we’re likely to see a warm summer but I doubt we’d break the record again so soon. Wouldn’t rule out a top 5 day, though.

[Metwatch]

15 hours ago, WYorksWeather said:

Is it that you think the Coningsby event was very exceptional, on the order of a 1 in 200 chance at the moment in any given year, or do you think it's higher than that in any random year, but that circumstances this year don't favour it?

A bit of both. It was quite an exceptional event even with today's climate, and this year well it just feels like there hasn't been as much of a buildup to it compared to spring 2022 where it was drier. Of course we've now entered a period where soil moisture is now prone to change dramatically which lasts until early autumn, but we won't find out if we'll see such dry soils this year until we're comfortably in a 2 week dry spell, perhaps this upcoming week is the start of a fairly lengthy dry spell we just can't know with certainty as of today.

I'll go for a guess and say 40C may only be reached once or twice again between now and the 2050s, and we're very unlikely to see it this decade. Typical highest temperature of the year in recent decades is still in the mid 30s.

[WYorksWeather]

 Metwatch Interesting set of points here - I guess the thing that gives me pause about only a couple more 40C temperatures up to 2050 is the fact that we've seen 37-38C quite frequently in recent years (not yet 50% of the time though, of course). I guess we will soon find out. A lot depends on whether we keep seeing temperatures approaching 40C in the years ahead, or whether the last 5 years starts to look like a bit of an anomaly, with a return to annual maxes mainly in the low to mid 30s rather than high 30s.

[Summer8906]

 BlueSkies_do_I_see Probably if we got weather typical of the first half of the spring in July, we'd get conditions typical of most recent Julys!

22 hours ago, ANYWEATHER said:

Southern Europe this year will get one if not the coldest summer on record, and the UK will be lucky, to get 30c

Mind you Southern Europe and the UK often trend on opposite directions. We saw that last year when July 2023 was dangerously hot in parts of southern Europe, but dull, wet and cool by day here. By contrast August 2022 was thundery and relatively wet in Greece, and 1976 was apparently one of Southern Europe's coolest summers on record.

If we fail to reach 30 here, I suspect Southern Europe will have another hot summer. Likewise if Southern Europe is unusually cold, it would imply low pressure there and probably anticyclonic E-lies here, hence warm and sunny.

 

Edited May 5 by Summer8906

[Summer8906]

 WYorksWeather I'd probably add to that:

- A significant chance of 2024 being the wettest year on record in the UK.

Simply because the year so far has been so wet, and the August to December period trends wet as a matter of course, particularly in recent years.

Edited May 5 by Summer8906

[Summerlover2006]

 Summer8906 2007 is another great example of this trend one of the hottest summers on record for southern Europe one of the wettest on record here