What No Castle?

[Graham Easterling]

Typical recent morning cloud base.

Marazion this morning

Below the cloud the visible is generally good or even very good.

Sennen - Cape Cornwall is around 5 miles

But once you rise into the cloud it's frequently been <400m. It was very thick above 50m when I drove to Helston on Tuesday. At sea level on the prom you could see several miles down the LIzard.

The forecast tends to give up trying to predict where the cloud base is a and just forecast poor for everywhere. It has been generally a very low cloud base rather than sea fog. There was a patch of sea fog in Pernzance yesterday afternoon. Lands End airport has had it's heaad relentlessly in the cloud since Monday, causing havoc with the flights. They should fly from Sennen beach at low tide!

It's very muggy!

Graham

Penzance

[Ashley haworth-roberts]

The Met Office and UKHSA have issued amber heat alerts for parts of England including the south west - and somewhat to my surprise they're already in force (I had expected upgraded and/or expanded heat alerts to come into force from Sunday). (I suppose an amber heat alert would not produce a higher temperature in west Cornwall than a yellow heat alert would in Leicester or Nottingham.)

[Freddie]

It's purely the UKHSA who issue heat health alerts, nothing to do with the Met Office.

It's a heat health alert, not a temperature forecast.  The population demographic comes in to any calculation of alert level, along with things like pre-existing NHS demand.

The level is an indication of the likely impact on health services due to the weather.  Amber on these warnings decodes as medium likelihood of medium impacts.  Yellow as medium likelihood of low impacts.

Tl;DR: You are misinterpreting the warnings.

https://ukhsa-dashboard.data.gov.uk/weather-health-alerts/heat

[Graham Easterling]

In Cornwall the big difference between the BBC forecast (which has been consistently low) and the MetO forecast (which has been consistently accurate) during warm/hot spells continues. This irrespective of which coast, and whether the wind's onshore or offshore/

For Penzance next week - wind tending onshore

                          BBC    MetO

Monday             22        26

Tuesday            21        24

Wednesday      21        23

For Newquay (offshore wind)

                        BBC    Meto

Monday            24       28

Tuesday           21       26

Wednesday     22       26

I assume meteogroup are aware.

Graham

Penzance 

[Graham Easterling]

Correction, Penzance MetO forecast for Wednesday is 25C.

Graham

[Ashley haworth-roberts]

Heat-health Alert service - Met Office

[Freddie]

It's the UKHSA who issue the warnings, not the Met Office.  The UKHSA obviously gets its weather data from the Met Office to help them inform their decisions.   It's a heat health alert, not a temperature forecast.  The population demographic comes in to any calculation of alert level, along with things like pre-existing NHS demand.

The Met Office does issue extreme heat warnings as a part of its National Severe Weather Warnings Service - but it doesn't attempt to forecast demand on health and social services.

[Graham Easterling]

Updated

                       BBC    MetO

Monday             22        26

Tuesday            22        26

Wednesday      23        28

For Newquay (offshore wind)

                        BBC    MetO

Monday            24       28

Tuesday           23       26

Wednesday     24       29

It's interesting to see some of the temperature forecasts for over the sea off the north Cornwal coast 9pm Thursday

On the subject of warm sea water, the press keeps going on about the recent Octopus bloom off the SW as being down to global warming, and whay a disaster it is. In fact it's happened on several occasions before. Whilst the take crabs/lobsters out of pots, it's a net gain for many local fisherman, due to the price Octopus gets, many in Newlyn are perfectly happy. In 2 years time it'll be back to normal.

Graham

Penzance

On Thursday, 18 June 2026 at 17:37:37 UTC+1 Graham Easterling wrote:

[Ashley haworth-roberts]

Some confusion over amber alerts (more amber heat health ones currently run until Friday at least in England):  Extreme heat alert extended with Wales due to hit 38C - BBC News

[Metman2012]

Do you think that when the Met Office issues a heavy rain warning and the EA issue flood warnings that both will finish at the same time? The rain will stop but the effects will continue, possibly for some time. Similarly  the heat warning ceases when the temperatures drop (please!) after Thursday, but the effects will continuer for a while.

[Ashley haworth-roberts]

If you're asking me, I agree. I was making the point that the headline on the BBC News Wales article seemed to confuse two different amber warnings/alerts that ended at different points in time.