Drivers have been asked to go somewhere else if the car parks at busy beauty spots reach full capacity.
It comes as May 30 could be the hottest day of 2023 so far, with the Met Office forecasting temperatures could reach 25C in parts of the country.
Car parks at Loch Lomond and the Trossachs National Park began to fill up early on Tuesday, with visitors told enforcement officers were out to tackle dangerous parking.
The Inveruglas, Rowardennan and Balmaha Visitor Centre lots in particular reached capacity shortly before 11am.
Park authorities also warned blocking access and parking illegally could prevent emergency services getting through to the park.
On a similar day in 2021, more than 40 fines were handed out to drivers who had parked illegally and “risked lives” at the national park.
The west of Scotland is the most likely area expected to experience soaring temperatures on Tuesday.
STV meteorologist Sean Batty said: “The good weather is set to continue through this week in the west of the country with temperatures probably reaching their highest point on Wednesday before coming down a degree or so on Thursday and Friday.
“On Tuesday, temperatures will reach 24-25C around Perth, Aviemore, Inverness, Fort William and Glasgow.
“Top temperatures on Wednesday are likely around Fort William, Tyndrum, Lochawe, Inveraray, around Loch Lomond, Glasgow and Paisley with 26C possible.
“It should be noted that UV levels are near their highest level now with burn times down to around 20-30 minutes and frequent reapplication of sun tan lotion is highly recommended, as well as seeking shade during the afternoons.”
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