00:00Hi there, I've been a meteorologist for almost 20 years and this week it's one of the most
00:04exceptional weeks of weather I've seen in my career. A red extreme heat warning in force
00:08for Wednesday, Thursday, amber for Monday to Thursday. And it's not just about the expected
00:13temperatures this week. Though they are extreme, there are a number of factors that have informed
00:19those extreme heat warnings, including overnight temperatures, as well as the duration and
00:24extent of the heat, and perhaps one of the most important things, the humidity, because
00:29when the UK all-time temperature record of 40.3 Celsius was set back in July 2022, dewpoint
00:37temperatures were in the single figures. This week, they're likely to be in the low 20s.
00:42Dewpoint temperature is an indication of the moisture in the atmosphere. In other words,
00:46it's a proxy for humidity. And that means that the humidity this week will be on a different level
00:52compared with July 2022, making it much more extreme and more dangerous than what we saw
00:58a few years ago. Why is it so humid? It's because of the source of the air. It's coming
01:02further towards the southwest and that Atlantic. Moist air is being caught up in a developing area
01:10of high pressure across central and northwestern Europe, which is intensifying over the days ahead.
01:14And underneath that high pressure, the Atlantic air gets compressed, squeezed and heated through
01:21compression, allowing for day-by-day temperature increases and those temperatures peaking on Wednesday
01:26and Thursday this week, aided, of course, by very strong sunshine each day.
01:32We start off Tuesday with strong sunshine across the UK. Perhaps some thunderstorms clearing the
01:37east of England first thing. One or two other showers for northern England, parts of Scotland.
01:41Otherwise, it's blue skies widely up and down the UK. Just some patchy medium and high-level cloud
01:45here and there and temperatures rising quickly. We're going to see several degrees higher temperatures
01:52compared with Monday. We're talking about widely across Scotland and Northern Ireland into the 20s,
01:59if not the high 20s, and for England and Wales into the mid-30s of Celsius. The most likely high
02:06temperature on Tuesday, 37 Celsius. That would break the June temperature record. 90% chance of that
02:12record being broken on Tuesday. 35.6 Celsius. It currently stands. And that record has held since 1976.
02:21But if we don't beat that record on Tuesday, it's almost certain it will happen on Wednesday and
02:26Thursday as temperatures rise further. Here's the amber extreme heat warning on Monday and Tuesday.
02:30A large part of England and Wales covered. It then gets more extended further north. And a red warning
02:36added for Wednesday because it's just going to get hotter and hotter, not just by day, but by night as
02:41well.
02:41These are the overnight temperatures Tuesday into Wednesday. Widely the high teens, low 20s in
02:46places. And of course in the UK, not many homes have air conditioning. Our homes really struggle
02:51to cool down with this kind of weather. So uncomfortable nights, really quite oppressive for
02:58sleeping. Some patchy cloud in the far north on Wednesday with some showers. Elsewhere, it's
03:02unbroken blue skies and very strong sunshine, very high UV levels, allowing temperatures to rise.
03:11Again, mid to high 20s across parts of Scotland into Northern Ireland and then widely across
03:16England and Wales. A very hot day indeed. We're talking about widely the mid 30s, if not the high
03:2330s. 39 Celsius, the most likely high temperature on Wednesday afternoon. But with aerobars of two
03:31degrees, that means there's a range of likely temperatures between 37 and 41 Celsius. The all-time
03:36temperature record, of course, is 40.3 Celsius. There's a 20% chance that will be broken on
03:42Wednesday or Thursday. But it's not just about those remarkably high daytime temperatures.
03:49Dewpoint temperatures are as follows. This is Wednesday afternoon. High teens, low 20s in
03:55places. That really is a sign of how oppressive the heat is going to be, how high the humidity
04:00will likely be. Now, on Thursday, there's a change across northern Scotland. We've got
04:04more cloud and some outbreaks of, at times, heavy rain. Elsewhere, a bit more cloud in
04:09the west, some showers and always a chance of a lively thunderstorm breaking out as temperatures
04:13rise elsewhere. And we're talking about very isolated thunderstorms where they occur, frequent
04:18lightning, hail, gusty winds and torrential rain. But most people will keep the sunshine and
04:24the extraordinarily high temperatures. Look at that, 37 Celsius in Cardiff. Other parts of
04:29Wales could be even higher. And we're talking about a large part of England seeing temperatures
04:33above 37 Celsius, if not 39 Celsius. So widespread, oppressive and extreme temperatures. In two parts
04:42of Scotland, we're reaching the high 20s, if not the low 30s. For the north of Scotland, it's a
04:47different story once again. It's warm, any showery rain easing, but we're not seeing those extreme
04:53temperatures that we're seeing across this part of the UK. That's where we've got amber and red heat
04:58warnings. Now, a lot of people say, well, we enjoy this kind of heat when we go to Spain
05:04for holiday or whatever, but it's a different story, isn't it, compared with going on holiday,
05:07staying in an air-conditioned hotel, sitting by the pool all day, and in a country where their
05:13infrastructure and their buildings are set up to deal with this kind of heat. In the UK, of course,
05:17we don't have infrastructure to deal with this kind of heat. We can expect power cuts and travel
05:22disruption as temperatures rise through the week, and more worryingly, wide population, wide adverse
05:30health impacts, not just for vulnerable people, but for the fit and healthy, especially if you're
05:35outside doing anything that requires physical exertion. So make sure you stay safe during this spell of
05:41exceptional heat and humidity. Stay hydrated, stay out of the sun as it reaches its peak during the
05:48middle part of the day. Stay protected from the very high UV. Keep your buildings cool, of course,
05:54and look out for each other. Make sure that you check in on people who may be on their own,
06:00vulnerable people in the community, and so on. Finally, on Friday, there is a sun respite for some
06:06parts of the UK. It's still going to be hot towards the east of England, still lots of sunshine around.
06:10Further west, we've got showers and thunderstorms developing, a lot more cloud, and less hot wind
06:16coming in from the south and southwest. It's still going to be very warm, mid-20s widely, low 30s,
06:23perhaps mid-30s to the east of England, but we've lost that truly exceptional heat. And it turns a bit
06:28cooler and fresher again into the weekend. We've got low pressure in the west. That's going to send some
06:33weather fronts towards the UK, bringing cloud and some showers or thunderstorms into the north and west
06:37as we go into the weekend. Staying drier with a ridge of high pressure remaining towards the
06:42southeast, but you can see the really quite extreme heat is being shunted towards the continent. So,
06:49the weekend promises something a little more comfortable, even if there are some showers
06:53and thunderstorms to watch out for. We'll keep you updated on that, of course, but in the meantime,
06:56stay up to date with our forecasts here and our warnings, and make sure you stay safe by following,
07:01well, sensible advice where possible. Bye-bye.
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