The Met Office has issued a yellow weather warning for heavy rain in Scotland on Friday through into Saturday and it will ease on Sunday.
The weather warning comes into force from midnight on Friday until 06.00 on Sunday morning and many areas will be hit with heavy rain and of 50mm, but in some places Scotland will have between 100 to 150mm on higher ground.
Met Office Chief Meteorologist Matthew Lehnert said: “Rain is expected to become heavy and persistent across much of Scotland later on Friday and is likely to continue throughout Saturday. There is an increasing likelihood of disruption and flooding from this heavy rainfall, particularly across western Scotland.
“We’ll continue to review warnings in the coming days so it’s important for everyone to stay up to date with the latest forecast for their area.”
However, for the rest of the UK at the same time, some unseasonably warm air will move across much of the country from the south.
Meteorologist Alex Burkill said: “The jet steam is going to push its way northwards ahead of the weekend, which will allow for some very warm air to come in from the south.
“As we go into the weekend frontal systems will remain trailing across Scotland as this warm air moves into the south. For many further south it will be a fine, dry day on Saturday with temperatures getting to highs of around 25C, which is unusually warm for the time of year.
“By Sunday, it’ll be a more widely dry and sunny day for many. Highs or around 26C or even 27C in isolated spots is possible.”
RNLI National Water Safety Partner, Samantha Hughes, said: “With warm weather forecasted, we are likely to see people visiting the coast and inland waterways. As it is outside of the summer season, not everyone will be able to access a lifeguarded beach so we’d like to remind people what to do if they find themselves struggling in the water.
“Remember to float to live. Tilt your head back with your ears submerged, try to relax and breathe normally, move your hands to help you stay afloat. When it is safe, then swim to safety or call for help. If you see someone else in danger at the coast, please call 999 or 112 and ask for the Coastguard.”