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Outrageous warm air advection! istheukhotrightnow.com

Simon Lee @simonleewx.com · 22/09/2026

GEFS is basically going for the Pacific Trough regime for the full subseasonal run. El Niño's North Pacific teleconnection activated and locked? simonleewx.com/gefs_north_a...

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Simon Lee @simonleewx.com · 19/09/2026

BBC News with yet another bizarrely weak way of saying “Climate change is driven predominantly by burning fossil fuels and will continue until net zero emissions are reached.” www.bbc.co.uk/news/article...

“Recent climate data combined with record heatwaves have given weight to the argument against further exploitation of fossil fuels.”

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Simon Lee @simonleewx.com · 18/09/2026

The nascent Arctic stratospheric polar vortex at 10 hPa (~30 km). What lies ahead this winter? Seasonal forecasts suggest a weak vortex in the second half of winter, likely driven by increased upward Rossby wave propagation from a deepened Aleutian Low in response to El Niño. earth.nullschool.net

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Simon Lee @simonleewx.com · 15/09/2026

Spotted some awesome fluctus clouds (Kelvin–Helmholtz waves) earlier this evening

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Simon Lee @simonleewx.com · 14/09/2026

The sudden stratospheric warming that took place in January 2009 remains one of the most spectacular atmospheric dynamical events ever observed. The poleward eddy heat flux anomaly associated with it reached 5.6 sigma – the largest N Hemisphere wintertime anomaly in the satellite era.

Time–pressure cross-section of ERA5 meridional eddy heat flux anomalies for Nov 2008 to March 2009 with respect to a 1979/80 – 2025/26 climatology. Negative absolute eddy heat flux is hatched. The max anomaly is 5.6 std dev at 10 hPa during the Jan 2009 SSW onset.

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Simon Lee @simonleewx.com · 14/09/2026

Broadly also consistent with a 2 sigma Pacific Ridge regime, which also features a SE ridge

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Simon Lee @simonleewx.com · 11/09/2026

Climate deniers on LinkedIn writing perfect climate science exam questions

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Simon Lee @simonleewx.com · 10/09/2026

8 years ago, I tweeted side-by-side maps from NASA GISS showing global temperatures in 1976 and 2018 – both hot summers in the UK. It subsequently went viral and was printed in the Daily Mail! The 2026 version is stark. Two locally extreme summers separated by 50 years of global climate change.

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Simon Lee @simonleewx.com · 07/09/2026

Intense squall passing through to St Andrews just now — a nice “welcome back” to our undergraduates, and a taster of what the Scottish weather can do for those new to the area!

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Simon Lee @simonleewx.com · 31/08/2026

IFS analyses suggest there have been 42 days of the Greenland High regime in summer 2026. The only other summers to have seen more are 2012, 2016, 2019 and 2023. doi.org/10.1029/2025GL119421

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Simon Lee @simonleewx.com · 26/08/2026

Summer 2026 is closing out with yet more of the Greenland High regime simonleewx.com/ecmwf_north_... This is consistent with the increased frequency and persistence of this regime in summer doi.org/10.1029/2025... although the anticyclone this year has often been slightly further west than typical.

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Simon Lee @simonleewx.com · 25/08/2026

Interannual variability in global mean temperature is most strongly related to temperatures in the tropics, here shown by correlating detrended global and gridpoint temperatures. There is very little relationship with temperatures over Europe and many parts of Asia.

A map of the correlation between local and global annual-mean 2 m temperature from ERA5 over 1979–2025, with the linear trends removed.

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Simon Lee @simonleewx.com · 20/08/2026

New paper from Jaewon Lee, Yutian Wu, and me published in @agu.org GRL examining the role of North Pacific weather patterns in modulating stratosphere-to-troposphere ozone transport ➡️ doi.org/10.1029/2026... @climate.columbia.edu @earthscista.bsky.social

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Simon Lee @simonleewx.com · 11/08/2026

This is much better — fossil fuels actually get a mention 👏 www.bbc.co.uk/weather/arti...

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Simon Lee @simonleewx.com · 07/08/2026

I've updated the archive of ERA5 daily-mean 10 hPa 60°N zonal-mean zonal wind time series plots on my website to include the complete 2025/2026 plot alongside a list of the dates of all 59 major sudden stratospheric warmings in ERA5. simonleewx.com/10-hpa-60n-z...

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Simon Lee @simonleewx.com · 06/08/2026

Gonna teach a whole class this autumn using only this map (ok, it probably won't be *only* this map, but woah, what a forecast! The ENSO and teleconnection lectures are going to be even more fun than normal 🤓)

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Simon Lee @simonleewx.com · 05/08/2026

Updated the NAM archive on my website to include last winter simonleewx.com/northern-ann...

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Simon Lee @simonleewx.com · 03/08/2026

I’ve said it before, but every time I open the Met Office app I find myself baffled by this visualisation. In this example, it turns out that it means yesterday was warmer than any of the following 7 days are forecast to be, while today is the coldest (or joint coldest).

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Simon Lee @simonleewx.com · 28/07/2026

Cheeky quasi-shelf cloud on the leading edge of some intense frontal rainfall in east Fife this evening (photo at 19:48)

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Simon Lee @simonleewx.com · 24/07/2026

Cairngorms wildfire appears to have affected local cloud formation — notable hole in the cloud deck today, perhaps through locally reduced relative humidity? Imagery: Terra/MODIS via worldview.earthdata.nasa.gov

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Simon Lee @simonleewx.com · 23/07/2026

Evening run spent contemplating how dry things are here. No rain recorded at Leuchars since 5 July.

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Simon Lee @simonleewx.com · 21/07/2026

Extremely amplified Atlantic Ridge regime present, with a possible Greenland High/negative NAO-type pattern by the end of the month. More at simonleewx.com.

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Simon Lee @simonleewx.com · 16/07/2026

“England’s green and pleasant land” becoming “England’s brown and scorched land” — effects of a long-lived heatwave and little rainfall on vegetation in England evident in these images from NOAA-20 today (left) and 18 July 2024 (right) during closer to average conditions.

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Simon Lee @simonleewx.com · 15/07/2026

Our shiny new Gill WindMaster sonic anemometer is moving closer to its initial deployment! 👀 😀 (not pictured: having oodles of fun creating various breezes/turbulence just to see what it looks like at 10 Hz)

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Simon Lee @simonleewx.com · 08/07/2026

Great to be at @exeter.ac.uk for the @rmets.org Annual Weather and Climate Conference 2026!

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Simon Lee @simonleewx.com · 04/07/2026

While I fully support explaining the specific meteorological conditions behind a heatwave, I still cannot understand not giving any mention to climate change. (Screenshot from a BBC article.)

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Simon Lee @simonleewx.com · 27/06/2026

Today’s GFS 18Z for 11 July showing max temperatures in England reaching 41°C Not to be taken as a deterministic forecast. However, this suggests that yet more extreme heat is possible in the next few weeks, which is made more likely and intense by climate change driven by burning fossil fuels.

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Simon Lee @simonleewx.com · 26/06/2026

Developing heatwave across the eastern US consistent with the Pacific Ridge regime approaching +2 standard deviations. The PR regime is the warmest regime on average in this region in summer.

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Simon Lee @simonleewx.com · 25/06/2026

Firth of Forth from Fife about 30 mins ago

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Simon Lee @simonleewx.com · 23/06/2026

This afternoon, I asked faculty, staff, and research students in the School of Earth & Environmental Sciences @earthscista.bsky.social for their predictions/guesses for the highest temperature that will be recorded in the UK this week. With 34 responses, our ensemble mean is 39.2°C.

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Simon Lee @simonleewx.com · 21/06/2026

Something no one has ever seen before: a Met Office forecast for somewhere in the UK (in this case, Reading) with two consecutive days of 40°C Whether or not this happens, the fact it is within the range of possible scenarios should give a loud warning of the climate we are now in

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Simon Lee @simonleewx.com · 20/06/2026

THIS IS ABSOLUTELY NOT “NORMAL SUMMER WEATHER” FOR THE UK — ESPECIALLY IN JUNE! (Record is 35.6°C) We are seeing the effects of climate change due to human activity playing out. Image is the latest Met Office forecast for London

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Simon Lee @simonleewx.com · 18/06/2026

ECMWF forecast Z500 anomalies for 27 June 2026 vs ERA5 Z500 anomalies for 19 July 2022, the UK's hottest day on record. The atmosphere is evolving towards a state conducive for extreme heat across northwest Europe.

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Simon Lee @simonleewx.com · 09/06/2026

While the climatological probability of the Pacific Trough regime is smallest in summer (~20%), current subseasonal ensemble forecasts suggest a notable and persistent suppressed likelihood. An example of more confidence in what the regime *won't* be, than what it *will* be?

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Simon Lee @simonleewx.com · 29/05/2026

This is NOAA's 20CRv3 Z500 anomalies from psl.noaa.gov/cgi-bin/data... for MAM 1921

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Simon Lee @simonleewx.com · 26/05/2026

If you’re going to use this meme as Greenpeace do here, at least use it properly — “hottest spring of your life so far” (closer to Homer’s original line) It’s extremely unlikely to be the coldest spring of the rest of your life due to natural variability, but it will be among the colder ones.

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Simon Lee @simonleewx.com · 25/05/2026

Interestingly the circulation pattern responsible for the extreme heat in the UK doesn’t project strongly onto any of the four Atlantic regimes — we’re in a decaying phase of a Scandi Blocking regime. Caveat that these regimes specifically might not be the best descriptors of the large-scale flow

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Simon Lee @simonleewx.com · 25/05/2026

Another record shattering heat extreme

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Simon Lee @simonleewx.com · 22/05/2026

A pleasure to host @timwoollings.bsky.social, Ken Mylne, @hcbloomfield19.bsky.social & @drchriswhite.bsky.social yesterday for the annual @earthscista.bsky.social symposium, this year on "From dynamics to impacts: Weather in a warming world". Thank you all for visiting and giving such great talks!

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Simon Lee @simonleewx.com · 20/05/2026

BBC also manage not to mention climate change, even when discussing the unusual nature of 30°C in May 🤷‍♂️ www.bbc.co.uk/weather/arti... I’m a bit baffled

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Simon Lee @simonleewx.com · 18/05/2026

I’d rather be chasing today’s Moderate risk in Kansas, but this fun little pileus on some shallow convection over northeast Fife will have to suffice

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Simon Lee @simonleewx.com · 14/05/2026

A big congrats to Josh Duffield, supervised by @drmichaelbyrne.bsky.social, for passing his PhD viva today with @ruthgeen.bsky.social and me as examiners. Some fascinating work on extreme temperatures that was a pleasure to read and discuss! 🥳 @earthscista.bsky.social

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Simon Lee @simonleewx.com · 07/05/2026

Great to present our work at EGU today investigating increased summertime Greenland blocking from a regime perspective — one of the largest model–observation trend discrepancies. Check out the paper in GRL doi.org/10.1029/2025...

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Simon Lee @simonleewx.com · 06/05/2026

Oh, the temptation… what Executive Editor wonders lie down this mysterious corridor? #EGU26

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Simon Lee @simonleewx.com · 04/05/2026

EGU 2026, here we go! Excited to see so many familiar and new faces, and hear all about the fantastic science everyone is doing (and maybe one or two beers, too) 😀

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Simon Lee @simonleewx.com · 27/04/2026

If you're heading to EGU next week, check out CL4.2 "The dynamics of the large-scale atmospheric circulation in past, present and future climate" – some really interesting talks & posters in there! I'll also presenting some of my work with Lorenzo Polvani looking at N American weather regime trends.

Screenshot of abstract for "Recent summertime North American weather regime trends in a very large seasonal model ensemble"

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Simon Lee @simonleewx.com · 19/04/2026

I've implemented a North Atlantic weather regime classification following the same method we introduced for North America, yielding NAO+, Atlantic Ridge, NAO– and Scandinavian Blocking (plus No Regime = nearer climatology than any regime). simonleewx.com/ecmwf_north_...

Stacked bar chart showing probabilities of four weather regimes (positive NAO, Atlantic Ridge, negative NAO and Scandi Blocking) plus No Regime

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