The Met Office has issued a yellow weather warning for much of the south east of England, and certain areas of the UK may get between 50 and 70 mm of rain on Saturday.
The warning will cover the area from Portsmouth, Hampshire, to Ipswich, Suffolk, and will be in effect from 6 a.m. to 1 p.m.
It comes after Storm Lilian on Friday severely disrupted travel.
Expect a slight inconvenience in travel while under the yellow warning.
Eslick, Liam, Met Office
The PA news agency was informed by Met Office meteorologist Liam Eslick that rain is expected to arrive from the South West and continue during the early hours of Saturday morning.
He said: “We are expecting quite a bit of rain in that South East corner.
“We’re expecting between 15 and 30mm, but in exposed spots and higher hills we’re looking at up to between 50mm and 70mm, which is quite a bit of rain to fall in a short space of time.”
The warning comes ahead of what could be the busiest August bank holiday on the roads on record.
The RAC estimates 19.2 million leisure trips by car will be made over the weekend, with 3.2 million on Friday alone.
This is the highest since the motoring services company began recording data for the summer bank holiday in 2015.
Mr Eslick said: “With that yellow warning, expect some small travel disruption.
“I know it’s the start of the bank holiday so people may be out and about trying to get to their holiday destinations.
“We do say take care when driving on roads, stick to the main roads where you can because more local tracks could see some surface water.
“So do take care when travelling around through Saturday morning.”
The heaviest of the rain is expected to move away around mid-afternoon, but showers will linger around central and south east England, as well as western Scotland.
A wind warning was in place across northern England and North Wales until 11am on Friday, with Storm Lilian bringing widespread travel disruption including delayed and cancelled flights.
“Winds aren’t expected to be too much of an issue on Saturday though,” said Mr Eslick.
“It’s mainly going to be the rain.
“Winds will be pretty light in the south of England, though you may get the odd gust around the very far South East through the English Channel.
“But mainland is going to be pretty light.”
It will be a lot calmer coming into the Bank Holiday Monday and it will be nice to have that extra day this weekend to enjoy
Liam Eslick, Met Office
Moving into Sunday, conditions are expected to ease – though some showers are forecast in the east, Northern England and southern Scotland.
Winds will pick up once again and it will be blustery for much of the UK.
But, according to the Met Office, this will not be as strong as the winds on Friday morning.
Looking ahead to the Bank Holiday Monday, Mr Eslick said: “Monday looks like the best of the days.
“There will be more in the way of some sunshine and winds are expected to ease.
“It will be a lot calmer coming into the Bank Holiday Monday and it will be nice to have that extra day this weekend to enjoy.”