A low pressure area moving in from the southwest, bringing heavy rain and thunderstorms, began heading across Finland on Wednesday.
North Ostrobothnia and Kainuu are expected to be the hardest-hit regions over the next few days, possibly with precipitation reaching record levels.
"There will be heavy rainfall on an axis running through North Ostrobothnia and Kainuu. The low pressure area will also rotate over the region on Thursday. There will be some showers and thunderstorms in the south," reports Yle Meteorologist Joonas Koskela.
In Ostrobothnia, along the west coast, rainfall on Wednesday and Thursday is expected to reach 20-40 mm. However, over the next few days, the heaviest downpours are likely to hit North Ostrobothnia, North Savo, and Kainuu, where total rainfall may average 40-60 mm.
July has been rainier than average so far. In some places, rainfall has been 100 mm above the monthly average.
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Daytime high temperatures are forecast to remain close to 20C degrees on Wednesday, for most parts of the country.
On Thursday, the heaviest rains will hit central regions, while southern Finland will see lighter showers.
On Friday, the low pressure area responsible for this week's rain will gradually move off to the east and precipitation will decrease.
"On Sunday, rain showers will be developing again, but despite this, in terms of temperatures the weather will remain quite summery," says Koskela.