Hurricane Bertha has been battering the islands with gusts of more than 90mph, leaving thousands of homes without power.
The storm is currently moving across the Atlantic, with the remnants set to reach Europe towards the end of the week.
Andy Ratcliffe, of MeteoGroup, said: "The moisture associated with the hurricane could well lead to us having some heavy rain across the UK towards the end of the week. All parts of the country will be affected.
"There will also be a new low-pressure system caused by the disturbance from the remains of Bertha, leading to more unsettled weather. It could be quite breezy at times."
Mr Ratcliffe said the bad weather was here to stay, with no signs of any further heatwaves like the UK has enjoyed so far this summer.
He added: "There will be some fairly heavy rain tonight and into tomorrow and further spells on Friday and into the weekend but there will be some dry spells in between.
"Things are looking generally unsettled for the time being."