19/07/2017 Weather for the Week Ahead

Hello there. Our weather is in the process of changing.

Already that change has brought something quite dramatic in places.

Some thunderstorms creeping up from the south.

Tuesday started off innocuously enough

with blue skies for our Weather Watcher

there in Falkirk,

but look at the cloud that turned up in Plymouth.

See the undulating pattern in this cloud structure?

That shows you just how unstable the atmosphere became.

Those storm clouds eventually delivered

some thunder, some lightning,

and a lot of rain in places.

During Wednesday, this little weather front here

is going to continue to bring some thundery downpours

northwards across the country.

This cold front out west

will eventually complete the change, if you like,

and leave us all with some fresher air.

But we're still going through that transition

during the day on Wednesday.

Quite a messy day,

bands of thundery downpours

pushing across the country.

Eastern areas still very warm, quite humid -

30, 31, maybe 32 degrees across East Anglia.

More cloud, though, for western parts

of England, for Wales.

Could see some further thunderstorms

turning up in North Wales,

maybe eventually northwest England

through the afternoon.

A scattering of showers and thunderstorms

across Scotland,

and for Northern Ireland we'll see

increasingly wet conditions

spreading from the west. Again, there could be

some thunder and lightning mixed in.

But this rain is associated with that cold front

that I showed you a moment ago.

As these rain bands work quite erratically

eastwards during Wednesday night and Thursday,

eventually we will allow that fresher air

to sweep its way in from the west.

Actually, a lot of dry weather around on Thursday,

but look at the temperatures.

Way down on where they have been.

17 in Glasgow,

perhaps still up to 22 degrees there in London.

Through Thursday night into Friday,

it looks like we're going to spin up this little area

of low pressure and bring it in

across the British Isles.

Quite an unsettled look to the weather, I have to say.

We'll see this band of rain working its way through.

Some of that rain could be on the heavy side,

blustery winds with that.

Even once the rain band has cleared, some sunshine, yes,

but also some showers pushing into the northwest.

16-21 degrees.

Low pressure stays with us

into the start of the weekend.

Just pivoting around on top of the British Isles,

so there'll be further showers

through the day on Saturday.

Some spells of sunshine as well.

But those temperatures -

get used to values like these -

15 to 21 degrees.

Now for the end of the weekend,

low pressure essentially stays in charge.

It drifts a little bit further eastwards

and allows high pressure

to try to build its way in from the west.

High pressure would of course change things

back to a more settled weather set-up.

So is that going to happen?

Well, yesterday I showed you the jet stream.

I showed you this bend in the jet stream.

The jet stream bending its way northwards.

This is where the high pressure sits, to the south of the jet.

If this bend worked its way in across the British Isles,

it would allow the high pressure to build its way in.

But actually, through next week,

it doesn't look like that's going to happen.

It looks like the jet stream will stay, essentially,

right across the country.

That will keep us very close to areas of low pressure.

On balance, it looks most likely

that low pressure will remain the dominant feature.

So what does that mean next week?

Well, it means some spells of rain, some drier intervals as well.

That high pressure not too far away.

Fairly cool and often fairly breezy.

So how will our weather change next?

Well, join me at this time tomorrow.