Thursday 30th July 2020

One very hot day ahead. And then a return to changeable conditions.

Thanks to Jonathan for the photograph.

Tonight will be clear, warm and rather humid in a southerly breeze, 18’C.

Friday starts sunny and will quickly become hot, it could be 30’C as early as 10am. A cold front will be approaching from the west later in the day, and there is a small chance, say around a 20% chance of a thunderstorm mid/late afternoon with torrential rain. A similar kind of chance of a bit of rain, and around a 60% chance that it remains dry but with more cloud. As often is the case, the breakdown and chances of any thunderstorms will remain uncertain right until the time.

Maximum temperatures will depend on exactly what happens with this cold front and how much cloud/rain it generates. I expect 33’C to be reached, I would not rule out 36’C. And it will be humid.

However, it will become less hot fairly quickly during late afternoon – temperatures probably peaking around 2pm, give or take. Variable cloud overnight, still warm and humid but becoming less so as the night goes on, 18’C.

Saturday will still be very warm, but nothing like Friday, and we are back in a more westerly flow having lost the southerly.

There will be sunny spells and variable amounts of cloud. A small chance of an afternoon shower. Very warm, around 24’C. Mostly clear overnight, down to around 12’C.

Sunday sees more sunny spells. Some cloud will bubble up, particularly around the lunchtime period, and there will be a small chance of an afternoon shower. Warm, 23’C. Fairly cloudy overnight, probably some rain but the extent and timing uncertain at this stage, 15’C.

Monday is a bit uncertain. It looks like a decaying low pressure will be heading towards the south of the UK, either brining cloud and bits of showery rain – or sunny spells and showers. Rather cool if cloudy, though on the warm side if sunny. It should be mostly clear and dry overnight, around 13’C.

Tuesday is also uncertain – good job I am not planning to do anything more exciting on my week off than clean the fridge. The general pattern looks like a deepening area of low pressure will be heading towards Scotland.

Exactly where the low pressure will be and associated rain fronts will determine our weather – it could easily be 15’C with strong winds and heavy rain, or we could end up very warm and humid with hazy sunshine – the weather front staying to our north.

Guess what? Wednesday is also a bit uncertain, the low pressure probably decaying but bringing some heavy showers, and likely warm.

What I am more confident about (though by no means 100%) is that Thursday will see high pressure in a more favourable position, similar to the end of the current week, allowing very warm air to spread up from the south again.

So the more likely outcome is Thursday sees sunny spells and temperatures around 25’C – give or take a couple.

Assuming we go for this hot southerly plume then the most likely outcome for Friday would be a hot and sunny day. 30’C easily. Maybe more. Maybe I haven’t booked the worst week to have a holiday after all?

At some point under this plume scenario a breakdown will come (thundery?!), but more likely than not the heat will last at least to Saturday.

Not bad for heat lovers or those with trusty air conditioning units.

Have a good weekend…I’ll update on tomorrow’s possible thunderstorm, in the morning, if there is anything to update you on. If you don’t hear from me than I have no further information!

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