The Met Office has issued a yellow weather warning for heavy showers and thunderstorms in Northern Ireland as majority of the country will be hit by a deluge of rain.
The extended Coronation weekend has brought typical British weather as rain descended on Charles and Camilla when they were anointed King and Queen in a service which took place on Saturday.
That was the complete opposite on Sunday as Brits basked in warm temperatures as high as 22C in some places as the Coronation celebrations continued with a special concert at Windsor Castle.
But with an Atlantic weather system sweeping in through the course of the week, Britain will be pummelled by more wet conditions on Bank Holiday Monday which could cause travel chaos.
A yellow warning for heavy showers and thunderstorms are in place for the whole of Northern Ireland between 12pm and 9pm on Monday. This means there could be some damage to a few buildings as well as the possibility of flooding.
Temperatures in the morning will remain mild due to extensive cloud cover across the UK, with Aberdeenshire and the Northern Isles failing to reach double figures.
But the wet weather from the Atlantic will work its way from the southwest and hammer much of the country with heavy rainfall.
Met Office meteorologist Greg Dewhurst said: "It is all change yet again with our weather after a fairly bright sunny day on Sunday. We've got wet weather on the way through Monday.
"In the west, the set of the Atlantic weather system start moving in here, bringing some outbreaks of rain as we head into Monday morning, some of this rain could be heavy at times. The wind starting to pick up along the Irish Sea coast too."
He added: "It is grey start for many of us, a wet start, particularly in the west. This rain slowly pushes eastwards through the day, perhaps East Anglia, parts of Kent holding on to a bit of brightness until later on.
"Behind the rain, it brightens up for Northern Ireland and Scotland, but the risk of some very heavy showers developing, some thunderstorms, hail and some localised flooding possible."
The mercury will certainly not reach the highs of Sunday but "in brightness we could still reach 20C" for Northern Ireland and East Anglia.
For the rest, it will be between 15C and 17C and with the mixture of cloud and rain it will feel "muggy".
The heavy rain will persist, particularly in England and Wales as we head into Monday evening, with the thundery showers in Northern Ireland and western Scotland also easing off.
UK five-day Met Office forecast
Today:
Early brightness in the east will be replaced with cloud and rain, heavy at times, which will move east through the day. Brightening up across Northern Ireland and later western Scotland with heavy showers and thunderstorms developing.
Tonight:
Scattered heavy showers clearing east across northern areas with clear spells and a few fog patches in the northwest. Elsewhere, rain clearing slowly east but remaining rather cloudy. Mild.
Tuesday:
Early rain in the east clearing to a mixture of sunshine and scattered showers. Some slow moving heavy showers and thunderstorms in the south and east during the afternoon.
Outlook for Wednesday to Friday:
Sunshine and showers Wednesday and Thursday, locally heavy with thunder but becoming dry for most Friday. Temperatures close to average but with mainly light winds, feeling warm in any sunshine.
