The September Heatwave in South West England

The United Kingdom Health Security Agency has issued a yellow Heat-Health Alert for South West England between 2 PM today and 9 PM on Sunday:

According to an associated Met Office press release:

Official heatwave criteria will be met for large parts of southern UK this week, with temperatures likely to exceed 30°C in some places.

Temperatures will be on the rise in the early part of this week, likely peaking on Wednesday and Thursday with 32°C possible in isolated spots in the southeast.

Met Office Deputy Chief Meteorologist Mark Sidaway said: “High pressure is situated to the southeast of the UK, which is bringing more settled conditions with temperatures on the rise through the first half of this week. While the highest temperatures are expected in the south, heatwave conditions are likely across much of England and Wales especially, with parts of Scotland and Northern Ireland also likely to see some unseasonably high temperatures.”

“An active tropical cyclone season in the North Atlantic is helping to amplify the pattern across the North Atlantic, and has pushed the jet stream well to the north of the UK, allowing some very warm air to be drawn north. It’s a marked contrast to the much of meteorological summer, when the UK was on the northern side of the jet stream with cooler air and more unsettled weather.”

Although very warm, there are some breezy conditions in western areas which could subdue the feeling of the temperatures for some…

In addition to high daytime temperatures, which could see official heatwaves be observed from as early as Tuesday in some spots, it will remain uncomfortably warm overnight, especially in the south, with a chance of tropical nights, which is when overnight temperatures remain in excess of 20°C.

The highest overnight minimum temperature for September on record is 21.7°C, and this record could be threatened on Wednesday and Thursday nights in particular.

Here are some temperatures recorded today across Devon and Cornwall according to the Met Office’s “unofficial” Weather Observations Website (WOW):

The Met Office forecast for West Devon currently looks like this:

[Update – September 5th]

A variety of different weather models are now suggesting that temperatures in West Devon will reach 27 or even 28 °C this weekend:

If that proves to be the case it will beat the 26 °C that Lisa the LEAF recorded on her trip to Holsworthy yesterday afternoon.

The UKHSA’s Heat-Health Alert for South West England has been updated to “amber” status between noon today and 9 PM on Sunday:

[Update – September 6th]

A misty sunrise this morning:

The Met Office forecasts a “sunny” day, with temperatures rising to 27 °C this afternoon:

[Update – September 9th]

The sun is out this morning, causing some lens flare on the slightly hazy picture of Yes Tor:

The Met Office’s rain radar web page shows that there’s been some rain overnight, enough to cause a sewage pollution incident in Plymouth:

It was rather misty on the north coast yesterday afternoon, so Chivenor has dropped off the Starlings Roost heatwave map, but as measured at Exeter Airport the heatwave has officially lasted 6 days so far.

The forecast is for another day with temperatures exceeding the heatwave threshold of 25 °C across South West England:

[Update – September 10th]

There has been some more rain overnight:

That has resulted in a nice clear view of #Dartmoor this morning:

If today’s Met Office forecast proves to be accurate, a maximum temperature of 24 °C means the heatwave in West Devon is over, after a grand total of 7 days:

To be continued…

Jim Hunt

I've been programming computers since the late 60s. In those days they didn't have computers in schools, so we had to build our own. What can I program next? Will I have to build it first?

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This Post Has 2 Comments

  1. Jim Hunt

    Here is this afternoon’s Met Office WOW temperature map for 14:00 to 14:59:

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