Met Office spokeswoman Nicola Maxey said that tropical storm Chris, which is building on the US east coast and is predicted to become a hurricane, “will influence the weather but we cannot tell what that influence will be at the moment because it is still developing”.
There is still “uncertainty” about the possible track it will take and it would be an ex-hurricane by the weekend when it may hit the UK.
Meteorologist Aidan McGivern, speaking in a Met Office Facebook post, said: “Developments on the other side of the pond could very well disrupt weather patterns in the vicinity of the UK.
“Tropical storm Chris is predicted to become a hurricane and move north over the next few days.
“(By the weekend) Chris is likely to join the jet stream and its remnants are likely to be carried towards the UK.
“Now, those uncertainties mean there are big differences in the forecast for the start of next week.
“One projection showing low pressure just to the west of the UK is bringing wind and rain, but on another Chris is barely there.
“One common theme emerging from the start of next week is that low pressure will be a little closer and the weather will turn more changeable than we have seen recently.”
Much-needed rain is on the way but it is still too early to write off the summer as warm weather is still expected over the coming week.
Average summer temperatures are 19C (66F) but across the UK we have seen 10C above that, according to Ms Maxey.
She said a “blip” in the current hot weather, which is not down to Chris, is seeing temperatures in the south east drop to around 23-25C (73-77F) and further north to 21-22C (69-71F) in Birmingham or 17-18C (62-64F) in Newcastle but temperatures “will increase a few degrees to the weekend”.
Ms Maxey said: “Certainly next week after ex-hurricane Chris has passed through we are looking at weather that is more mobile or normal (for this time of year) but that is not to say that we will not have another hot spell of weather.”
She said that ex-hurricanes like Chris happen regularly.