10 Day trend - Any sign of the weather patterns changing? 13/11/19 - video Dailymotion

Met Office

The main themes of the UK forecast remain cold with spells of further rain. The weather patterns stay that way well into next week, with perhaps a subtle change later next week, Alex Deakin explains.

Transcript

00:00Thanks for joining me for this 10-day

00:02trend, where we look at the weather

00:04patterns and trends for the medium

00:05to long range.

00:07Now, in the short range, there's some

00:08more severe weather on the way.

00:10Plenty of heavy rain to come and

00:12there are weather warnings in force.

00:13I'm not going to go through those in

00:15detail here.

00:16If you want to know the latest on the

00:17severe weather, download the Met

00:19Office app or visit our website.

00:21Now, I'm looking at the longer range

00:23trends, which are for more of

00:25the same. It does look as if

00:26generally well into next week, it

00:28stays unsettled.

00:29Further spells of rain and often

00:31blustery conditions and always

00:32staying on the chilly side as well.

00:34There are hints that perhaps things

00:36could turn a little bit milder

00:38as we go through it next week.

00:39But the weather patterns kind of

00:41been stuck in a rut now for a

00:43number of weeks.

00:44Let's take a look at the big

00:45picture. This is the jet stream

00:46notice it driving down to the

00:48southwest of the UK, up across

00:50Greenland and then driving south.

00:52And in this position, it generally

00:53allows low pressure systems just to

00:55sit in here and mill around

00:58across the UK.

00:58That is why we keep seeing those

01:00spells of rain.

01:02Now, why are we seeing this

01:03repeating weather pattern?

01:04Well, one of the reasons is

01:06over in the United States, we're

01:07seeing a repeated pattern here.

01:09Cold plunges, areas

01:11of cold air drifting south from the

01:12Arctic over eastern parts of

01:14Canada and eastern parts of the

01:16United States. And we get another

01:17one of those pushes of cold air

01:19driving south this weekend.

01:21Why is that important?

01:22Well, the cold air derives south,

01:24clashes with the warmer air over

01:25the tropics, and that gives the jet

01:27stream a bit of oomph, a bit

01:29of extra energy.

01:30It pushes it to the north, up

01:31across Greenland, and then that

01:33drives down to the south

01:35to the west of the UK.

01:37Now, this is the chart for Sunday,

01:38but it does look remarkably like

01:40that one I showed you a minute ago

01:42for the one on Wednesday.

01:43So again, that weather pattern is

01:45set to repeat for the next few days

01:47and we stay on the cold side of the

01:49jet with low pressure nearby.

01:51Now, those low pressures will bring

01:53further spells of rain, one

01:54particularly across eastern areas

01:56into Friday night and Saturday

01:58could cause some further problems.

01:59And then this one just flirting

02:01with the southwest on Sunday.

02:03But notice it's not going to rain

02:04everywhere all weekend.

02:06Some places will be between those

02:07two weather systems.

02:08So there will be dry spells around

02:10this weekend, but just don't

02:12expect it to be warm.

02:13We stay on the cold side of the jet,

02:15so it's going to be chilly.

02:16Morning frosts are very

02:17possible and also some fog

02:19patches as well.

02:20But as I said, it won't rain

02:21everywhere all weekend.

02:22There will be some dry periods.

02:24We do need to flag that rain

02:25potentially across eastern England,

02:27certainly on Saturday morning.

02:30What about beyond the weekend?

02:31Will we continue with this

02:33repeating weather pattern?

02:34Well, chances are, yes,

02:36I'm going to show you a Hofmuller

02:37plot now. Now, it's quite a

02:39complicated graph, but it

02:40does show the repeated cycle

02:43quite clearly.

02:44Now, this is longitude along

02:46the x-axis to the bottom.

02:47There's the UK at zero, the Greenwich

02:49meridian. This dotted line

02:50represents where we are now.

02:52Things above that are going

02:54back in time and things below

02:56it are going forward in time.

02:58So this is the projection.

02:59It's basically a slice through

03:01mid-latitudes, medium

03:03or upper levels of the atmosphere

03:05where red represents

03:07higher pressure and blue

03:09represents lower pressure.

03:10Now, don't worry too much about

03:11deciphering the detail.

03:12I just really wanted to show you

03:14the repeated pattern as we go back

03:15in time here over the past several

03:17weeks. You can see that we've had

03:19this repeating pattern with high

03:21pressure, low pressure, high

03:22pressure. That's across the

03:23Mid-Atlantic and there's the UK

03:25stuck in that slightly blue zone.

03:27That's why we've kept on seeing

03:29low pressure systems across the UK.

03:31And it's also important because I

03:32want to show you going forward,

03:34that pattern is likely to stick

03:36around well into next

03:38week. So we're likely to stay with

03:40low pressure close to the UK.

03:42One subtle difference, though,

03:43that I want to highlight, just that

03:45red blob there, areas

03:47to the east of the UK

03:49just showing signs that the high

03:50pressure here may intensify,

03:53may get a little bit stronger next

03:54week. And if we see slightly higher

03:56pressure over the near continent,

03:58it means the lows may

04:00not be sitting as close to the UK.

04:01They're more likely to be a little

04:03bit further west.

04:04And if that's the set up, this is

04:05the most likely set up through next

04:07week. It means that the winds

04:09perhaps could start coming more in

04:10from the southwest.

04:11Now, that's important for a couple

04:13of reasons.

04:14It suggests that through next week,

04:15perhaps it won't be quite as

04:17cold. I'm not suggesting it's going

04:18to get warmer. We generally stay on

04:20the cold side of the jet, but

04:22it won't be quite so cold.

04:23Temperatures back closer to average.

04:25And it also means with the winds

04:26coming more in from the west, that

04:28it's western areas that are

04:30more likely to see the

04:31outbreaks of rain, which is good

04:33news with the flooding across parts

04:35of the east, of course, but not

04:37great news because it is very

04:38wet already across the west.

04:40So that's the themes into next week.

04:41Yet it remains unsettled.

04:43Low pressure will be the dominant

04:45feature, but we are more likely to

04:47see a subtle shift with more wet

04:48weather in the west compared to the

04:50eastern temperatures, perhaps just

04:52rising closer to average.

04:54As always, there's a lot of

04:55uncertainty. These are just the

04:57general trends.

04:57And as I said at the start, for the

04:59details of the very latest

05:01weather warnings, make sure you

05:02stay weather aware by visiting the

05:04Met Office website or following

05:06us on social media.

10 Day trend - Any sign of the weather patterns changing? 13/11/19

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