10 Day Trend – Thundery breakdown, then what? 24/06/20 - video Dailymotion

Met Office

A thundery breakdown brings an end to this week’s brief burst of heat. But what happens after that? Met Office meteorologist Aidan McGivern has this week’s 10 Day Trend.

Transcript

00:00Hello, and welcome to the Met Office 10 day trend.

00:04George II apparently said that the British summer consists of three fine days and then

00:09a thunderstorm.

00:10And that's certainly the case this week.

00:12A brief hot spell, then it all goes bang.

00:14Thursday night into Friday, the thunderstorms clearing the air and allowing more typical

00:20British summer weather to arrive from the west.

00:23And that means it will turn cool, changeable, without breaks of rain or showers this weekend

00:28and throughout next week.

00:31Actually, not everywhere has seen three fine days.

00:34Western Scotland and Northern Ireland has seen a wet week so far.

00:38But on Thursday, the hot sunshine extends right across the UK and temperatures will

00:43soar as a result.

00:45Thirty Celsius possible, Glasgow, perhaps the Murray coast as well, widely mid to high

00:49twenties elsewhere and across the heart of England as well as parts of Wales, 30 plus.

00:56I think the hotspots will be West Midlands, West Wales, 33 Celsius possible here or even

01:0234.

01:03If you don't like the heat, head to the coast.

01:05There'll be some cooler sea breezes here, but wherever you are, the sun will be really

01:09strong.

01:10We've just had the solar, the summer solstice.

01:13And that means with Thursday's sunshine, well, the sun is about as strong as it gets at this

01:18time of year with high or very high UV levels across the country.

01:24So make sure you cover up if you're spending time outdoors and hay fever sufferers take

01:28note.

01:29We're looking at high or very high levels of grass pollen as well.

01:33Another risk comes along later Thursday, and that's because we've got the heat in place

01:37across Western Europe, but looking at the Atlantic, the jet stream is beginning to make

01:43inroads.

01:44In fact, that's dipping just to the west of the UK, it's dipping to the south and it's

01:47scooping up areas of low pressure and much cooler air.

01:50And as that cooler air collides with the heat across Western Europe, well, it's all going

01:54to go bang.

01:56And on Thursday evening, well, it's across Western parts of the UK where we'll see those

02:00thunderstorms start to move in.

02:02Severe thunderstorms, hit and miss, as is always the case with thunderstorms.

02:06Not everywhere we'll see one, but where they do occur, they could cause issues.

02:10Now into Friday, it's across Central and Eastern Britain that those thunderstorms move.

02:15And again, the risk of severe thunderstorms in places.

02:18That's why the Met Office have issued yellow warnings for Western Britain on Thursday night

02:22and for Central and Eastern areas for Friday and into the start of the weekend.

02:27A thundery breakdown is expected with the risk of some very heavy rainfall in a short

02:32space of time, 50, 60 millimetres in a few hours, and additional hazards of frequent

02:37lightning, large hail, as well as gusty winds.

02:40Like I say, not everyone will catch one of these severe thunderstorms, but where they

02:44do occur, well, they could cause a few issues.

02:48Once they're out of the way, well, it soon starts to cool off.

02:50Another hot day in the east on Friday, but by the weekend, westerlies across the country

02:56and much cooler air.

02:58Now on Saturdays, there'll still be some heavy showers and thunderstorms about.

03:02They'll be moved along fairly briskly by the wind, so I don't think they'll cause so many

03:05issues as Friday's thunderstorms, but some sharp showers around, certainly, mixed with

03:10some sunshine and a keen breeze.

03:13On Sunday, I think there'll be some drier weather across southern parts of Britain,

03:15particularly later in the day, some sunshine even, but it will certainly feel much cooler

03:20with a breeze coming in from the west and some increasingly persistent wet weather for

03:25western Scotland, I think, developing through the day and continuing into Monday.

03:31For the start of next week, well, taking a look at the bigger picture, we've got the

03:34jet stream in a straight line, more or less, across the Atlantic and heading towards the

03:38UK, and that means that it will pick up further areas of low pressure and send them our way.

03:44Now, the jet stream has often been in a weak and fairly flabby setup through spring and

03:48early summer, but it's not unusual for this time of year, late June, to see that jet stream

03:52pick up some oomph and for the westerlies to return.

03:56In fact, climatologist Hubert Lamb called this return of the westerlies back in 1959

04:02a return of the westerlies because westerlies are the default weather for the UK, not this

04:08hot sunshine that we've got at the moment.

04:11What does that mean?

04:12Here's a map for the middle of next week.

04:15In fact, this is taken from the Met Office medium range computer model and there's a

04:1975% chance, according to that model, that this weather pattern will prevail next Thursday.

04:26That's quite a high percentage chance, looking that far ahead.

04:29In fact, it's the same weather pattern, more or less, throughout next week with low pressure

04:32to the west or to the north of the UK, these westerlies bringing breezy, cool and changeable

04:38weather.

04:39The weather models are in agreement that that's the kind of setup we can expect through

04:43to the end of this 10-day period.

04:46What they all vary on is, of course, where we'll see the showers and rain from day to

04:50day, but that's always the case looking ahead more than five days or so.

04:54But the general theme for next week is that it will be much cooler than we are experiencing

05:00at the moment.

05:01It will often be breezy and we'll have a mixture of rain or showers.

05:04Good news for gardeners and farmers, of course.

05:07Good news for people who don't like the heat.

05:09But if you do like the heat, make the most of the next day or two because it's not going

05:13to last.

05:14Back to normal next week.

05:16Find much more detail, of course, on the Met Office social media channels.

10 Day Trend – Thundery breakdown, then what? 24/06/20

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