22/09/2016 Weather for the Week Ahead

Hello. Low pressure systems, weather fronts, isobars,

some sunshine and some early-morning mist and fog -

the weather for the next week or so is a classic autumnal mix-up.

And it is often, no matter which way you measure it,

as of Thursday, because Thursday marks the autumn equinox.

All to do with the position of the Earth rotating around the sun,

and it's in such a position on Thursday

that day and night are pretty much equal,

so from now on,

the nights will be longer than the days.

We are pretty much in autumn, and you can

tell by weather fronts out in the Atlantic.

The first of those fronts fizzling out during Thursday,

just bringing cloud across central areas

and a few showers tracking eastwards.

Either side of that, some September sunshine

lifting temperatures potentially over 20 degrees

across East Anglia and the south-east,

more typical values elsewhere 15 to 17.

There'll be showers in the far north-west.

We'll see a few more showers in the evening

across Northern Ireland, Scotland,

north-west England,

but for many, it will be a dry night

and a cooler night

across the south and the east.

Some mist and fog,

but that will clear quickly and for most,

Friday is a fine, bright, dry day

with sunny spells.

Notice the wind starting to pick up,

another weather system in the far north-west.

Temperatures 15 to 19 Celsius.

That weather system drifts to the north of the UK,

but its trailing weather front

is the main player through the weekend.

Lots of isobars, so winds picking up,

and this front bringing a lot of heavy rain,

looks particularly soggy over western Scotland.

Turning wet across western parts of England and Wales.

Ahead of that front, southerly winds

yet again sucking up some warmth,

so we could, with hazy sunshine,

reach 23 degrees Celsius.

Some uncertainty about the timing of that front,

but it could be draped across East Anglia

and the south-east on Sunday morning,

potentially a damp start here.

It clears and then we see sunny spells,

a bit of a breeze,

temperatures close to the average

because we've got more of a westerly influence.

There'll be plenty of showers on Monday,

and behind me, things are

getting complicated out in the Atlantic,

and that's the main problem next week. Why so?

Well, not to do with this storm, Lisa,

but more to do with this storm, Karl.

It is a tropical depression.

It'll intensify and drift northwards.

As it does so, it's likely to get close to Bermuda through the weekend

and potentially may become a hurricane.

When these kind of storms start to drift north,

they interact with our weather

because they interact with the jet stream,

that fast-moving ribbon of air high up.

Usually, the jet stream drives the system

at the ground,

but when you've got something with as much energy as

a tropical storm,

or potentially a hurricane,

that can influence the jet stream,

so it adds to complications

and uncertainty, so the jet stream

tending to come in like this

through much of next week,

which means the wettest,

windiest weather will be across

more northern parts of the UK,

but we are also going to be

on the warm side of that jet,

and there's the potential

to draw up someone warm air,

especially around the

middle part of the week.

I'm using words like "potential"

and "possibly" because of Karl,

and the interaction grows the uncertainty

so generally next week, often quite blustery,

the wettest in the north-west,

but Karl adds uncertainty,

hints it might get a bit warmer.

We'll definitely be keeping you posted.

Watch this. It is amazing.