peacockreports.bsky.social
Head Meteorologist at MetSwift, working to revolutionise delivery of weather information.
LinkedIn: https://t.co/pUCAQfAfRP
948 posts
348 followers
54 following
Regular Contributor
Active Commenter
comment in response to
post
If it does finish 'warm' i.e. at least 1°C above the 1991-2020 average by my unofficial definition, then conditions in the rest of this month will have been warmer than in 95.2% of the years 1772-2024.
Warmest June in the CET record is 1826 (16.61°C). 2nd warmest 2023 (16.41°C).
comment in response to
post
For me I think 2020's August has the edge, featuring the most intense heatwave I've experienced first-hand in this country (in terms of combined duration & heat), plus the most extreme downpour with considerable flash flooding.
2022's was more pleasant though, & notably dry overall.
comment in response to
post
Overall, we can't really draw confident expectations for this evening. This isn't unusual for a setup with a lot of convective activity involved, because such activity interacts with the environment around it in a feedback loop, which means any modelling error rapidly amplifies.
comment in response to
post
Yet - very confusingly! - the overnight ECMWF run paints a very different picture, with a sprawl of lively activity across most of southern England.
Meanwhile GFS depicts the complex affecting SE England but doesn't have the feature in the west that AROME & UKV predict.
comment in response to
post
Overall, the guidance on that complex has shifted eastward, but this follows a westward shift yesterday, so it's hard to know if it's a true correction or just uncertainty on display.
There's also less activity modelled between the two features compared to yesterday's runs.
comment in response to
post
Yes, just the one run I think but possibly a deterministic one. The reality was fortunately less ferocious, though still notably hot for some 4-5 days.
comment in response to
post
Most likely, they won’t behave in the required way & 40°C won’t be reached in the UK again, but to even see it in the spectrum of plausible events just three years after 2022 is pretty extraordinary if you ask me.
comment in response to
post
So the takeaway from this should be that given the anomalously warm seas around the UK, the extent & intensity of heat build over western central Europe, & UK soils drying out next week, 40°C in England is deemed possible.
Only if weather patterns behave in a certain way.
comment in response to
post
Of course, the viability of this depends on whether it's feasible for similar net sinking of air to be achieved when the air is less dense up to at least the 850 hPa pressure level.
Or perhaps there are roles for relative humidity & mid-upper troposphere stability? A fascinating subject.
comment in response to
post
One hypothesis I can think of is that with the much above normal predicted temperatures (which largely exist at the 850 hPa level too) comes a simulation of reduced air density, hence lowered sea-level pressure, which could be offsetting a positive anomaly associated with the circulation pattern.
comment in response to
post
Seems plausible that June will be a warmer than average month as a whole.
If the latest ECMWF seasonal is near the mark on July-August (moderately sized 'if') with it's >= +1°C ensemble mean anomalies, the summer as a whole would be impressively warm.
comment in response to
post
Then for September, an intriguing signal appears for above normal SLP focused to the NW of the UK. Usually a harbinger of cooler than usual weather in N Europe, yet the temp anomalies are above normal, though not as much as in July-August.
Weak prec. signal except for wet in northern Scandinavia.
comment in response to
post
For August, the sea-level pressure signal becomes less distinct, yet the precipitation & temperature ones don't change much.
It's a notably hot forecast for the bulk of Europe, including most of England. Heatwave risk much above normal widely, especially in July.
comment in response to
post
For the remainder of next week, uncertainty emerges.
The largest cluster, just over half the ensemble set, keeps high pressure in control.
The other two clusters drift a low in during the weekend (hot for a time, then rainy, risk of ⛈️), though cluster #3 spares northern UK.
comment in response to
post
Now for a daring statement: From what I'm seeing, this is setting up to be a summer where, if the right weather pattern sequence played out, 40°C would be reached in the UK.
Fortunately for those who'd rather that didn't happen, that's a very big 'if'. Just not as big as usual.
comment in response to
post
Meanwhile here's the latest GFS deterministic run for 16 days time on course for something likely even hotter in the subsequent day or two.
Again, not something to be expected. The point I'm making is that there's sufficient heat to the south that such scenarios are plausible.
comment in response to
post
Further to this point, here's the result of ECMWF's latest deterministic run bringing some of that very hot airmass into play (in 12 days time, I'm not saying this will happen).
34°C at noon suggests a 36-37°C max, which exceed the 35.6°C June record held by 1976 & 1957.
comment in response to
post
Similar situation with Friday evening & following night. There's been a general trend to restrict the most intense thunderstorms to SE England (classic) but beyond that it's a bit of a guessing game for the details.
comment in response to
post
@petagna.bsky.social kindly informed me a few weeks ago that UKV has a bias toward too much cloud cover, especially low-based. Good example of that today!
comment in response to
post
However, a few have shifted the high further east, allowing very hot weather to spread northward from Iberia for at least a day or two.
A possibility to keep an eye on, nothing more at this stage.
comment in response to
post
With such a vast area of such hot conditions in place, the positioning of ridges over NW Europe will have a big impact on temperatures there.
Lately, model runs for next week have tended to favour an overhead position with any hot weather 'homegrown'.
comment in response to
post
Despite all the cloud, perhaps even partly because of it (reduced instability, fewer showers), rainfall to-date is only a little above the 1991-2020 average.
That might change tomorrow night, depending on how exactly the potentially thundery spell of rain shapes up.
comment in response to
post
After an initially very askew run, GEM's deterministic model has been fairly consistent on a scenario akin to what ECMWF's has been trending toward.
If the true outcome is like the latest GEM & ECMWF runs, it will be an impressive showing by GEM if you ask me.
comment in response to
post
Meanwhile, the GFS deterministic model has been flailing about, not really settling on any one outcome. It seems to be battling with a long-present bias toward depositing small cut-off lows near or over NW Europe (which hang about, producing showery, cool weather beneath).
comment in response to
post
Past experience suggests the most likely outcome is somewhere between UKMET & GEM, on the basis that the GFS scenario requires the low to become 'cut off' from the jet stream, which requires the setup (jet stream position etc.) to fall within a narrow margin.