Extreme, record-breaking heat is increasingly possible for Sunday and early next week. Until then, hot and often sunny – though some cloud, and temperatures drop a little before the weekend.

Thanks to Chris for the photograph.

The Met Office does have an amber warning out for heat – I know the temptation may be to downplay it “hot weather in summer, shock horror”, but heat is dangerous for some people. The one saving grace for this heatwave is that humidity should be relatively low.

This evening and overnight sees lots of high cloud, which will keep the warmth in – down to around 18’C so a rather warm night.

Tuesday sees high pressure in control and the heat remains – though a weak cold front will be slowly edging down from the north-west.

The sun will be much hazier than the last few days, with lots of high/mid level cloud – some sunny breaks, but generally hazy sunshine, and cloud tending to thicken somewhat later in the day. Hot, around 31’C. Fairly cloudy overnight as the weather front continues its slow progress south/south-east – you might even scrape a shower out of it, though most places dry. A really warm night – possibly no lower than 20’C.

Wednesday starts fairly cloudy, you might even get a little showery rain out of it – but also some hazy sunshine. More sunshine from lunchtime onwards, give or take, but often hazy. Less hot, 27’C, maybe a little more. Still quite a bit of high cloud overnight, though a somewhat fresher night, down to around 16’C.

Thursday sees good spells of sunshine. Some high cloud at times, some fair weather cloud bubbling up – more so in the afternoon, but sunshine is the game. The northerly breeze taking the edge off, but still getting to 26’C. Reasonably clear skies overnight and a much fresher feel – down to around 12’C.

Friday again sees good spells of sunshine. Some cloud around – some high cloud at times, and some fair weather cloud, but temperatures also on the up, reaching around 28’C, give or take. Clear skies overnight, down to around 13’C.

So you may remember that I said if low pressure developed to the west of Spain/Portugal, it could lead to unusually hot air heading our way. Well, low pressure will be developing to the west of Spain/Portugal in the latter part of the week and will be advecting much hotter air north.

Saturday looks like seeing low spells of sunshine, though hazy at times. Hot, somewhere between 28’C and 30’C most likely. The warmer nights will be back too, getting down to around 17’C.

Sunday has more of a southerly flow so will be hotter. Long spells of sunshine, a bit of cloud but generally just hot and sunny, perhaps very hot. A little uncertainty on maximum temperatures but most likely in the range of 32’C to 34’C – but I wouldn’t rule out anything in the range of 28’C to 36’C. A warm night for sure.

The more likely outcome for Monday is that it is very, or extremely hot. And sunny. Temperatures somewhere in the range of 33’C to 38’C, with a small chance of 40’C. Aha.

It isn’t certain, these kind of plumes are tricky to get exactly right a week in advance – the extremely hot air may not reach these shores, maybe it drifts further east of us – so it is still very possible that we just end up with ordinary hot weather. Likewise, the low pressure system from Spain/Portugal may well track our way and destabilise conditions, ie thundery showers, before the real heat gets here.

So there is some uncertainty – as there normally is a week away. But the more likely outcome is that Monday is very hot, with a small-moderate chance of record-breaking heat.

Following this is uncertain – the very hot conditions may last another day or two, or Monday may be the last day. Some form of breakdown with some thundery showers seems fairly likely early/mid week.

The more likely outcome for late next week and into next weekend sees more hot sunshine.

Next full forecast will be on Friday due to work social on Thursday evening.