19/08/2017 Weather for the Week Ahead

Hello there. We've been talking recently about how tropical storms

and hurricanes can throw computer models into a bit of a spin

and make forecasting weather here in the UK that bit more difficult.

Now, this area of the cloud has been named Tropical Storm Harvey,

it's heading into the Caribbean,

but this area of cloud here could develop into another storm

and that is further north

and could be entrained into the flow that heads across the Atlantic

towards the UK and we're seeing that at the moment.

Some of this cloud contains remnants of Hurricane Gert

combined with an area of low pressure

and it's making the forecast

that bit more uncertain,

even as early as Sunday.

Saturday looks fairly

straightforward, thankfully -

sunshine and showers.

The showers mainly across

the northern half of the UK,

not as many showers or as heavy showers

as we had on Friday

and it won't be as windy either,

but still not that warm for the time of year,

16 in Glasgow where we're likely to catch some showers,

21 in London where it's likely to stay dry.

Then as we head through the evening,

those showers will tend to fade away

because we've got briefly,

all too briefly,

a ridge of high pressure

building in across the UK,

so clearing the skies

and temperatures 10, 12 degrees,

similar to what we've seen recently.

First signs of rain, though,

arriving into the far south-west

towards the end of the night

and this rain contains

some of that tropical air

from that ex-hurricane.

Not much rain for the south-west

and Wales - at the moment

it looks like the wetter weather

is likely to be across Northern Ireland later

and further north and east across the UK

and it may well be dry

through daylight hours,

the sunshine turning more hazy,

but a decent day on the whole

and temperatures 18 to 20 degrees.

Now there may not be an awful lot of rain

from this ex-hurricane system,

but it's going to drag in some very warm air briefly

and some humid air too,

so you might as well find Monday,

Tuesday temperatures not far off

27 degrees, now that's mainly

the south-east of UK.

The warmer air coming in

behind this warm front here

and that will push some rain northwards

and eastwards overnight

and into Monday that rain quite slow-moving

across East Anglia and across

northern England and North Wales.

Again, the heavier rain

more likely for Northern Ireland,

perhaps into the south-west of Scotland.

So if we put the temperatures on,

you can see the difference

that we've got across

more northern parts of the UK

where temperatures are going to be up

to around 17 or 18 degrees,

whereas to the south

where we've got a conservative 24 degrees

there in the south-east, but it could be even

higher than that. It will be quite humid too.

And we still got some remnants of that humidity

and that warmth across the south

and south-east on Tuesday.

Further north, a messy mixture of showers

and some slightly cooler air,

so temperatures in that humid air

getting up to around 25 or so in London.

Now that brief warmth

is just going to be brief.

It's probably gone by Wednesday

and we're going to be cooling down

from the north as we see

a band of showers which could be

quite sharp heavy heading down

towards East Anglia and the south-east.

And we start later next week with low pressure

and it's slower to move away.

It does eventually move away out into the near continent

allowing a cool northerly airflow for a time.

Before, by the weekend, perhaps,

high pressure builds in across the UK.

Again, it's a bit slower and, again, there are uncertainties

across the computer models as to how far north the high will build.

Some of them only really build

the high briefly across more

southern parts of the UK,

allowing that Atlantic air

to come back in across the north

and bring with it the chance

of some rain, but everything's just that little bit slower now.

So we've still got some showers in the outlook at first

before the high pressure builds in,

but it may only hang around quite briefly

and more especially across the southern half

of the UK. But because of all those hurricanes or ex-hurricanes,

there's a lot to play for.