Parts of Scotland could be doused in up to 60mm of rainfall and lit up by lightning strikes after forecasters issued a yellow weather warning.
The Met Office warned of “torrential thundery downpours” and urged residents and business owners in parts of the Highlands and North East to be prepared for potential flooding along with spray on roads adding to journey times for drivers.
Some interruption to power supplies is also possible.
Some areas may experience rainfall of up to 60mm while a possibility of lightning has also been highlighted between 8pm on Friday and 8am on Saturday.
Higher ground of Angus, Aberdeenshire and East Highland are likely to see the heaviest downpours.
The warnings are in place from 8pm on Friday until 8am on Saturday and apply to the North East of the Highlands and through Perthshire up to Aberdeen.
“Rain will become heavy and persistent across Scotland from the south this evening, clearing later in the night,” the Met Office forecast states.
“Many areas will see 15-25mm, with some places, particularly higher ground of Angus, Aberdeenshire and East Highland seeing as much as 40-60mm.
“Lightning may be an additional hazard in a few places. Some disruption to transport and infrastructure is likely.”
Traffic Scotland and Network Rail also issued a warning and advice to travellers.
However, the rail network provider said they expect timetables to run as normal
In a tweet, Network Rail said: “We’re expecting some very wet weather this evening and into the weekend. We have been working with our infrastructure teams and train operators to prepare. We’re also likely to see strong winds and some lightning strikes in areas too.
“Across the country, teams have been preparing for this, checking known flood sites and our fixed pumps are ready for the wet weather. Engineers are making sure vehicles are loaded with spare parts in case lightning causes damage to any of our signalling equipment.
“We’re expecting all train operators to run a normal timetable, but our weather specialists are monitoring the forecast and actual rainfall totals closely in case we need to impose speed restrictions for safety reasons in the worst affected areas.”
Presenter Philip Petrie said: “As we head into the weekend things are remaining changeable, unsettled, and turning very wet and very windy.
“We currently have two areas of low pressure out to the west of Scotland, which are merging together into one low pressure which crosses north eastwards through Saturday and Sunday.
“This larger area of low pressure will bring with it heavy rain through Friday night and into Saturday morning, and therefore the Met Office have issued a Rain weather warning that covers two parts of the country.
“Starting at around 6pm on Friday we will start to see cloud and rain spreading in from the south – just in time for rush hour so we will likely see some disruption with spray and surface water on the roads, localised flooding and strengthening winds.”
He added: “With the heavy and persistent rain most places will see 15-25mm of rainfall, with higher ground locations possibly seeing 40-60mm. Lightning will be a major hazard too during this time.
“The Met Office warning comes into effect at 8pm Friday night and runs until 8am Saturday morning, but the hazardous conditions don’t end. During Saturday the main band of rain clears northwards, still affecting the Hebrides for much of the day, but behind it we see heavy showers moving in and because we will be directly under the centre of the low pressure it means very light winds.
“This in turn means the showers will be slow moving, so if you are caught under a shower it will feel quite persistent. So unfortunately not a great outlook for the weekend, and things look set to remain unsettled for the foreseeable.”