The country is already awash with water in its rivers and reservoirs so any further downpours could cause widespread problems today and tomorrow.
The Met Office has issued a yellow ‘be aware’ warning for thunderstorms beginning across most of the country around 11am today.
These should die out this evening but are forecast to return around the same time on Wednesday and rumble on until 10pm.
The warning states:” Flooding of homes and businesses could happen quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.
“Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services.
“Spray and sudden flooding could lead to difficult driving conditions and some road closures.
“Power cuts might occur and other services to some homes and businesses could be lost.”
As with previous alerts, weathermen stress that not everybody in the warning area will see the heaviest downpours.
But problems are expected, with 20mm (three-quarters of an inch) of rain falling within an hour in some spots and 30-40mm (up to 1.5 inches) falling in three hours elsewhere.
Today’s warning area includes the whole of Scotland, save for some parts of the Western Isles, Orkney and Shetland.
Tomorrow’s warning area is slightly narrower, but still includes most of the mainland.
Last night, the Scottish Environment Protection Agency has 15 flood alerts in place.
The agency’s most recent water scarcity report states that the country’s water levels have picked up significantly since a warm and dry spell was experienced in May and June.
The report says that river levels and soil moisture have improved, following rainfall across the Clyde and Solway areas.
Only eastern and coastal spots show lower-than-normal water levels for this timer of the year.
Communities have recently experienced the full effects of heavy, stormy, rainfall. Last week, parts of the A77 in Ayrshire were inundated by floodwater and power cuts were experienced in Kilmarnock.
At the weekend, roads were turned into rivers in Kilbarchan in Renfrewshire and train services were halted through Falkirk Grahamston after the tracks were submerged by water.
Yesterday “heavy flooding” on the railway resulted in “major disruption” on the west highland line, with services being cancelled between Glasgow and Oban and Mallaig.
A signalling fault also caused problems on the Glasgow to Edinburgh line.
On Sunday, part of a Premier Inn had to be evacuated at Grangemouth when floodwater left cars swamped.