10 Day Trend – Warming up but for how long will the sun shine? 18/09/19 - video Dailymotion

Met Office

The rest of this week will see temperatures rising and plenty of blue sky once some morning fog has cleared. A big change is on the way with next week having a very different look and feel. Alex Deakin takes us through these changes.

Transcript

00:00Welcome to the Met Office 10-day

00:02trend, where we take a look at the

00:03bigger picture and some of the

00:05flavours affecting our weather into

00:07next week.

00:08It's fair to say the next week will

00:09taste very different to this

00:11week. If you're enjoying the

00:13sunshine, we'll make the most of the

00:14next few days, because for many,

00:16the sun will last through the rest

00:18of this working week and into the

00:19first part of the weekend.

00:21And the days will be getting

00:23warmer as well.

00:24But we are going to see a little bit

00:25more mist and fog around in the

00:27mornings, particularly Thursday and

00:29Friday morning.

00:30After that, we will see the change.

00:32Now, there's a bit of uncertainty

00:34about exactly when we'll see the

00:35change, but basically by next

00:37week, expect much

00:39cooler weather, cloudier weather.

00:41And with some places hardly seeing a

00:43cloud this week, that won't be too

00:44hard. And yes, after

00:46a pretty long dry spell for some, we

00:48will finally start to see a bit more

00:50rain coming in.

00:52Let's take a look at the bigger

00:53picture. We can see why the weather

00:54has been so fine and settled this

00:56week. The jet stream is driving to

00:58the south, way out

01:00in the Atlantic, then to the north.

01:02And this ridge

01:04is allowing the surface high

01:06pressure to dominate.

01:07It's been sitting across the country

01:08for a number of days and will

01:10continue to sit across us through

01:12Thursday and Friday.

01:15Now, as the nights are getting

01:16longer and temperatures drop

01:18off at night, it will turn cool

01:20enough for some mist and fog patches

01:22to form, particularly close to the

01:23centre of the high where the winds

01:25are light. So expect some mist and

01:26fog, as I say, on Thursday and

01:28particularly Friday morning.

01:30But the high is gradually

01:32ambling away.

01:33It's very slowly

01:35just drifting to the east and that

01:37is allowing southerly winds to pick

01:39up and they will waft up some

01:41warmer air by the time we get to

01:43Friday and Saturday.

01:44So in the sunshine, it'll feel quite

01:46a bit warmer by the time we get to

01:47Saturday. How much warmer?

01:49Well, temperatures like last weekend

01:51could be back into the mid-20s

01:52across parts of the south,

01:55depending exactly on the wind

01:56direction, because if it's coming in

01:58from the North Sea, parts of the East

01:59Coast could be a little cool and

02:01it perhaps won't be quite as warm in

02:03the West because here we're

02:05starting to see a change on

02:06Saturday. There'll be more cloud

02:07rounds and that's because a weather

02:09front is approaching.

02:11Now, there's a bit of uncertainty

02:12about the exact timing of this

02:14weather front.

02:15That's because it's a blocking

02:17area of high pressure that we've had

02:18in control.

02:19And when that breaks down to

02:21low pressure and weather fronts,

02:23there's always a bit of uncertainty

02:24about exactly how that happens.

02:26The computer models struggle a

02:27little bit with that changeover.

02:29So as I say, the timings of this

02:31weather front open to a bit of

02:32uncertainty.

02:33But what this weather front will do

02:34is bring more cloud into the West

02:36and eventually some showery rain.

02:38Actually, it's developing into an

02:39area of low pressure, which will

02:41throw rain across many areas by the

02:43end of Sunday.

02:43And this cold front sweeps away

02:45that warmer air, so it will be

02:47turning cooler and fresher.

02:48And with isobars pinching closer

02:50together, it will also turn quite

02:52blustery. So a very different feel

02:54by the end of Sunday.

02:55That transition happening this

02:57weekend, the sunshine or

02:59maybe still to start for many on

03:01Saturday when it could be pretty

03:02warm, but it will be turning wetter

03:04and cooler during

03:06the weekend.

03:07Now, I said there's a fair bit of

03:08uncertainty about the track and

03:10position of that weather front as

03:12it moves across the country on

03:13Sunday. Why so?

03:14Well, there's a number of factors

03:15going on. If you look at the bigger

03:17picture again for the early part of

03:18next week, you can see it's

03:20pretty confused as areas of low

03:21pressure, in particular, the jet

03:23stream is no longer in a

03:25straightforward pattern.

03:26It's trying to cut off here and

03:28there's another stream of it there

03:30across the near continent.

03:31And it's also developing out

03:33in the Atlantic. So it's a bit of a

03:34messy scenario with what's going on

03:35high up in the atmosphere.

03:37There's also events going on across

03:39Greenland that are affecting things.

03:40And also this area of low pressure

03:43is adding an extra complication

03:45because of where it's come from.

03:46Now, by the time we get to Monday,

03:48it looks like this will be bringing

03:49in weather fronts and isobars.

03:51So we'll see a spell of wet and

03:53windy weather. But there's a lot of

03:54uncertainty about the timing of

03:56this weather system as well,

03:57because if we

03:59track it back over

04:01the previous few days, coming

04:03back to the current position of

04:04that low pressure system, and we

04:06actually discover that low is

04:08currently a hurricane

04:10affecting Bermuda over the next

04:1224 hours or so.

04:14Now, it's a hurricane, lots of

04:15isobars on the chart there,

04:17very strong winds, and it's been

04:18driven by the warm waters over

04:21the tropics.

04:22As it moves further north, well,

04:23it will change.

04:25It won't be a hurricane anymore.

04:27In fact, by Friday, it's just an

04:28area of low pressure.

04:29Certainly by the time it approaches

04:30the UK, it's just a standard

04:32area of low pressure.

04:33But it is set to bring

04:35a spell of wet and windy weather.

04:36Notice how it's lost that warmth,

04:38that energy.

04:40And it could be affected

04:42by the jet stream.

04:43And that's why there's uncertainty.

04:45This low pressure will bring energy

04:46and that really confuses

04:48the atmosphere a little bit.

04:50And so there's always more

04:51uncertainty when you draw up

04:53one of these old tropical systems

04:54close to the country.

04:56But it may well get affected by the

04:57jet stream because the jet

04:59stream has changed position by

05:01early next week.

05:02And that's the big change for next

05:03week. Compare and contrast the jet

05:05stream this week.

05:06We saw it earlier up across

05:08Iceland and down to the east

05:10of the UK, allowing that high

05:11pressure to sit across us.

05:12Next week, the low the low

05:14pressures are being driven by the

05:15jet stream, which is much further

05:17south.

05:18So with the jet stream in this

05:19position, our weather patterns will

05:21be very different.

05:22It means we'll see low pressure

05:24systems moving pretty much directly

05:25across the country.

05:27Now, this is next week.

05:28The exact position of these lows,

05:31how much rain they bring, how

05:32strong the winds are, open to

05:34a lot of doubt at this stage.

05:36But the main themes, a big change

05:38on the way, a big change to much

05:40more changeable weather.

05:41We're not going to see endless days

05:43of sunshine. There will be spells of

05:45rain, but it probably won't rain all

05:46week. There'll be some drier and

05:48brighter spells in between.

05:49Very typical autumn fare,

05:51you may say.

05:52Now, for the very latest details day

05:54on day, always follow the Met

05:56office on social media.

10 Day Trend – Warming up but for how long will the sun shine? 18/09/19

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