Spring 2024

[kold weather]

 CryoraptorA303 im not sure that would have made any real difference between the date it happened and early August. Looking at the top 10 hottest days they all but one fall between 18th July and 10th August, interestingly 4 of the hottest days seem to be on either the 18th or 19th July, perhaps fluke but maybe suggestive of a peak heat date?

I'd also argue that between those dates any gain in sea temperatures (real marginal by that point to.be honest) is probably matched by an increase in night time length.

[Daniel*]

30C in March? That’s hilarious we haven’t even had 30C in May in 19 years in London (2005).

Edited February 21 by Daniel*

[CryoraptorA303]

14 minutes ago, kold weather said:

im not sure that would have made any real difference between the date it happened and early August. Looking at the top 10 hottest days they all but one fall between 18th July and 10th August, interestingly 4 of the hottest days seem to be on either the 18th or 19th July, perhaps fluke but maybe suggestive of a peak heat date?

Four? There's only three, and the only one on the 18th is 2022, so that's the same instance as the all-time record in of itself.

It's much more useful to look at the highest temperature for each day, and in those there is quite a clear peak in late July-early August with the last 10 days of July and the first 15 days of August holding the most 34°C+ days and by far the most 35°C+ days out of the year. From the 24th to the 14th, aside from the 29th, 30th and the 5th, every single day has reached 34°C, and the 29th and 5th might as well have reached 34°C. Most days of summer outside of that have not reached 34°C.

Here is July 19th's immediate surroundings:

You can see how much the 2022 heatwave sticks out in that crowd. Even the 2006 maximum would stick out quite severely.

Vs July 25th, August 3rd and August 10th's surroundings:

You can see that all three records stick out significantly less from their surroundings. It makes sense that the hottest days are clustered here, July 24th-August 10th is roughly the hottest three weeks of the year for most stations.

32 minutes ago, kold weather said:

I'd also argue that between those dates any gain in sea temperatures (real marginal by that point to.be honest) is probably matched by an increase in night time length.

There is barely any change in insolation by that point. There is just about one hour of daytime less on August 10th than on July 19th, and bear in mind there is a lag between sunrise and sunset in this direction, so the total insolation over the afternoon which is when temperatures peak will barely be lower at all. The overall increase in sea and airmass temperature, which is more significant than you give credit, will more than account for any loss in insolation. Also to bear in mind is the direction our hot air comes from, which is the south, and they don't see the effects of declining insolation until much later. Many if not most west coast climates have their hottest day in August, we are currently one of the exceptions due to a fluke.

In summation, latest July-early August will always be the favoured time for the very hottest temperatures in our climate, when all factors can perfectly align.

 Daniel* I don't think anyone actually expects such high temperatures to materialise anytime soon, this is just what is numerically possible with the same anomaly as Coningsby.

2005 isn't the last time we reached 30°C in May either. Hull reached 30.1°C in the 2010 heatwave and Inverailort reached 30.9°C in 2012. There is a world outside of London.

[kold weather]

⁸ CryoraptorA303 I agree with you roughly  on the dates but i just think you cant just ignore the 4 hottest dates ever recorded being recorded on the 18-19th July.

Therefore I'd extend your dates through to say 18th July to 10th August. In reality though we are debating miniscule differences!

Interestingly June 2019 is probably the hottest upper pattern I've ever seen, pretty similar in heat to July 22 (850hpa of just under 26c recorded) but the thickness was even more impressive and it was coming at ansolute peak isolation. A pro met worked out that using typical lapse rates would have led to about 42c. Unfortunately we imported a wicked north sea undercut. That would have been exceptional!

Anyway this is veering into summer territory.

One record I'm keeping a close eye on is the May CET, we've nor really even been that close in recent years and like Feb 1779 is one of those old holdups.

Sometimes those extreme temperatures people out feel unrealistic, but I think 10 years ago 21c+ in Feb would be unrealistic, 40c in July would be unrealistic. Pretty much every month there is a 4-6c record broken somewhere, so a May 35c is possible in theory.

[CryoraptorA303]

 kold weather

16 minutes ago, kold weather said:

I agree with you roughly  on the dates but i just think you cant just ignore the 4 hottest dates ever recorded being recorded on the 18-19th July.

Which is the fourth one? We have 36.5°C on July 19th 2006, 38.2°C on July 18th 2022 and 40.3°C on July 19th 2022. Two of them are in the same year so we can more or less assume the coincidence of 2006 and 2022 is a fluke.

18 minutes ago, kold weather said:

Therefore I'd extend your dates through to say 18th July to 10th August. In reality though we are debating miniscule differences!

Ok fair enough, and yes it is quite miniscule, maybe a 1°C difference.

18 minutes ago, kold weather said:

Interestingly June 2019 is probably the hottest upper pattern I've ever seen, pretty similar in heat to July 22 (850hpa of just under 26c recorded) but the thickness was even more impressive and it was coming at ansolute peak isolation. A pro met worked out that using typical lapse rates would have led to about 42c. Unfortunately we imported a wicked north sea undercut. That would have been exceptional!

That would've been our 2021 PNW heatwave before it happened. Absolutely terrible (or excellent if you hate the heat like me) timing.

20 minutes ago, kold weather said:

One record I'm keeping a close eye on is the May CET, we've nor really even been that close in recent years and like Feb 1779 is one of those old holdups.

A May heat spike is essentially unanimous in all suggested analogues so with these extremely high global temps this "may" be the year (don't laugh).

To be honest I don't refer to the CET much, it's quite useful in establishing long-term trends but pre-1860 the quoted figures are going to have a high margin of error due to the constraints of the available technology. These very old entries like May 1833 were almost certainly not warmer than more recent Mays but the same standards of measurement and technology we have today didn't exist then. Even today there is, in scientific terms, a high margin of error in records and they are constantly being adjusted. November 1994 being downgraded from 10.0°C to 9.9°C comes to mind.

[raz.org.rain]

6 minutes ago, CryoraptorA303 said:

That would've been our 2021 PNW heatwave before it happened. Absolutely terrible (or excellent if you hate the heat like me) timing.

34 minutes ago, kold weather said:

Given some of the ludicrous upper atmosphere temperatures we've seen in recent years and the growing persistence of Azores/Iberian highs, a PNW-style record destroyer occurring in NW Europe is seemingly a less ridiculous suggestion than it otherwise would be. I mean, France has arguably gotten pretty darned close lately. Some of the fantasy land ensembles were even suggesting 45° for Belgium last July.

[Metwatch]

16 hours ago, Rain All Night said:

And why is that, I'm assuming the reduced solar input compared to mid-July?

There is the element of the slightly weaker sun, but the main reason is we seem to get the strongest plumes and hottest air in July, and the infamous "weather goes bad once school holidays start" most summers from the end of July in many recent years. However Augusts 2020 and 2022 have started to buckle this trend and maybe that will continue with more August heatwaves in the coming years? We don't know.

Just made this graph quickly (I think the values are correct looking at Trevor Harley and for most of them Met Office climate summaries but not fully sure, could be a few errors within 0.5C), and you can see not much in a way of a rise recently. August 1990 had 37.1C for interest. Often quite variable year to year. (Also the title should be since 1995, didn't change it when I added temps until back to 1995)

July might look quite different if someone else wants to plot that.

7 hours ago, SunSean said:

always find it odd how May struggles to reach the 30c mark. We haven't touched it since 2005 in my area!

Yeah it seems to be a struggle to beat the spring records in recent years, but 2021 and 2018 have gotten close for March and April, I made another thread and post on that recently (might be better to continue the highest possible temperature records discussion there rather than here maybe!)

I explained one of the main possible reason for that here:

 

Edited February 21 by Metwatch

[reef]

Any chance we can discuss summer in the summer thread and leave this for Spring?

[CryoraptorA303]

9 minutes ago, Metwatch said:

but 2021 and 2018 have gotten close for March and April

2018 did beat the April record and by a degree as well. Unfortunately the Met Office continues to peddle the nonsense 29.4°C figure from 1949. 29.1°C in 2018 is the true record.

2021 also has the second warmest March day on record, so we're a lot closer to breaking these records than it might seem. May is the one we've struggled to reach really.

As for August, there's quite a clear increase in the average maximum. The 1990s-early 2000s simply had much more consistent Augusts.

Eventually we will see spring heatwaves of comparable magnitude to what we've been seeing in summer, it's just a matter of time. These extremes happened in the distant past so we know considerably more severe extremes are possible today.

[CryoraptorA303]

 raz.org.rain It's quite obvious by this point that we are getting closer and closer to the extremes we're talking about, it's just a matter of time.

[MP-R]

 CryoraptorA303 I don’t see why the 1949 figure is nonsense… 

[reef]

The Tornado and Storm Research Organisation (TORRO)

WWW.TORRO.ORG.UK

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TORRO is a privately-supported research body specialising in severe convective weather in Britain and Ireland

Only once you get to about 21st May do most days have records above 30C. I think these days its probably possible in the last few days of April but that would be pushing it. It would most likely require perfect synoptics, cloudless skies, no wind and well above average SSTs to do it.

26.5C is the highest in the first half of April. Most days in March are 21-22C before it picks up at the end.

Its often easy to forget Spring is quite a cold season. The average maximum doesn't hit 15C in most places outside of the south-east until mid-May.

[summer blizzard]

. Editing

Edited February 21 by summer blizzard

[summer blizzard]

In terms of my own Q2 thoughts;

 

QBO - Likely to be easterly and weakening given that we have already passed -1.8 for January. 

Years with 2 Q2 months below -1 (and at least -1 in April) are 1982, 1984, 1987, 1992, 1994, 2001, 2010, 2012, 2018, 2022. 

 

PDO - Likely to remain peristently negative given that it has blown through this Nino untouched

Years with all 3 Q2 months below -1 are 1991, 1999, 2001, 2002, 2008, 2012, 2021, 2022, 2023

 

ONI - Likely to weaken but remain positive given that we still hold moderate to strong raw ONI values.

Years retaining positive Q2 MEI values are 1980,  1983, 1987, 1992, 2005, 2015, 2019

 

As you can see, since 1979 (limited for standardised QBO values), there's not really a Q2 ONI-PDO match. Since ONI is probably the most important of the three, i would put 1987 and 1992 as primary anaologues but 2001, 2012 and 2022 as good secondaries. 

 

April - CET range is 7.7 to 8.7 when excluding the warmest and coolest. Mean is classic Atlantic High, Scandi Trough 

May - CET range is 11.8 to 13.1 when excluding the warmest and coolest. Mean is Atlantic/UK High (perhaps suggesting that the April pattern relents as the month progresses). Warm second half?

June - CET range is 13.5 to 14.9 when excluding the warmest and coolest. Mean is a Greenland High and southerly tracking Jet Stream. 

 

For interest and because it's a spring thread, i did apply these analogues to March. 

March - CET range is 5.2 to 8.0 when excluding the warmest and coolest. Mean is Atlantic Low, Scandi/Russian High. 

[WYorksWeather]

Still not a lot of certainty on the models tonight. I think we're still a few days away from being able to nail down the likely patterns for early March.

The ECM regime chart is showing the Scandinavian Block into early March as the likely regime. This is normally associated with cold.

However, it must be noted that the model assigned the Scandinavian Block for the period 15th-20th, which was of course very mild, so it's not a guarantee.

[raz.org.rain]

Fingers crossed!

 

[Weather Enthusiast91]

 raz.org.rain At the moment I'd take anything other than rain, whether it is spring warmth or a last minute wintry spell I don't care. I am just tired of getting drenched on my commute to and home from work.

[NEVES SCREAMER]

5 days to go. The cold and dark of winter gone again for about 9 months. Already daffodils emerging. The grass looking like it has a bit of strength in it. The sun has a bit of warmth in it. It's great !

[Barry Reynolds]

 NEVES SCREAMER Yes, very spring-like today in Hereford. Bright sunshine for a while, I could feel the warmth on my face.

[East Lancs Rain]

Wouldn’t it be great if we got a repeat of March 2012, April 2020 and May 2018 this spring? Especially after this awful winter. It won’t happen but we can dream!

[al78]

 East Lancs Rain Yes, but from the point of view of allotment cultivation, rain once a week.

[East Lancs Rain]

GavsWeatherVids has released his Spring forecast today.

 

 

[Markus03]

 WYorksWeatherYes, Scandinavian blocking seems to arrive over Western Russia for next week meaning that at least Finland will be dry. However the air isn't particularly cold as temperatures get to freezing only at nights while during the day will be freezing free in the South and Central parts of the country. So at the end of the day the wind direction likely won't come from the North East so you most likely won't see very cold tempeatures. The wind looks to come from the South East which is much more warmer for this time of year. So yeah, no beast from East so far but we'll see exactly what happens soon. But again, I don't think it's possible.

[Summer8906]

 East Lancs Rain I'd prefer something cooler than that to be honest in March and April, though not May. That amount of warmth and all the spring flowers would be gone by end of April! What I'd favour would be something like March 1995, April 2021 and May 1989.

 

Edited February 25 by Summer8906

[B87]

My ideal spring would be a repeat of March 2012, April 2011, May 2020, leading into a summer of June 2023, July 2018, August 2022.

Edited February 25 by B87