Heavy rain and thunderstorms look set to ruin football fans' plans to watch the Euro 2020 match outdoors tonight.
A yellow thunderstorm warning is in place for much of England and Scotland from 6am until midnight today.
There is also another thunderstorm warning including the Dumfries, Galloway, Lothian & Borders areas and Northern Ireland from 10am to midnight tomorrow.
The Met Office has also issued a warning for heavy rain for large swathes of the South West from 1pm until 9pm.
It means that tennis spectators hoping to attend Wimbledon or football fans planning to gather in pubs or fan zones for England's match against Ukraine at 8pm could see their plans spoiled by the wet weather.
Passionate England fans met in outdoor settings such as squares and parks, as well as beer gardens, to support the team during the previous football matches.
But if they are forced to change their plans due to severe weather conditions, they will still be able to meet indoors as long as they stick to coronavirus restrictions, including the rule of six.
Wimbledon fans who want to brave heavy rain to enjoy the tennis tournament will need to make sure they have their umbrellas or raincoats with them.
The weather alerts warn that people could see flooding to homes and businesses, delays or cancellations to transport services and also a danger that communities may become "cut-off".
Met Office forecaster Tom Morgan said: "We have two yellow weather warnings in place, the first covering the South West of England including parts of Cornwall, Devon and Bristol, which will see heavy and persistent downpours and even some flooding from Saturday afternoon.
"Another warning of thunderstorms will cover large swathes of central England, spanning from the south to north, starting from 6am on Saturday.
"These areas will see scattered, heavy showers, thunderstorms and even some hail."
Mr Morgan put this down to an area of low pressure over the UK, brought about by a jetstream bringing changeable, wet weather.
He added: "There are quite a few sporting events over the weekend, including England's Euro 2020 match against Ukraine in Rome at 8pm on Saturday.
"While the players will be playing in 28C temperatures, back in England spectators in pubs and fan zones will be hit with heavy downpours.
"It may also be a washout for tennis-goers at Wimbledon, who I'd advise to have an umbrella to hand, despite there being some sunny spells."
Those in Wales will be hit with wet and even thundery conditions on Saturday, while parts of Scotland and Northern Ireland will see mostly cloudy conditions along with some rainfall.
The beginning of next week will also see wet weather hit parts of the country, with showers in northern areas.
On Tuesday, windy weather is set to arrive from the South West, the Met Office said.
The weather will remain unsettled on Wednesday before more settled conditions move in by the end of the week.
UK 5 day weather forecast
Today
A very unsettled day across most of the UK as early showers and rain in the south spread northwards, becoming heavy and thundery at times. Parts of northern, eastern and southwestern England are likely to see the heaviest rain.
Tonight
Early evening showers and thunderstorms slowly fading away leaving many areas dry later. Still some showery rain over Scotland and the far south of England by dawn though.
Sunday
Warm sunny spells for many areas, but cloudier in coastal parts of eastern Scotland and northeast England. Heavy thundery showers also developing in many regions from late morning.
Outlook for Monday to Wednesday
Unsettled in the north with heavy, thundery showers, fine and dry in the south. An area of wet and unseasonably windy weather arrives from the south-west Tuesday. Remaining unsettled Wednesday.
