meteorology

Next week, the monthly forecast promises more than 20 degrees for a large part of the country. KARI PEKONEN

Foreca’s new monthly forecast promises that the weather will continue to be warm even until the beginning of October. Next week the temperatures will resemble July.

– The week starts out sunny for us and the temperatures are at the level of the usual mid-July, but as the week progresses, the weather becomes cloudier and rainier and at least a little cooler. The week as a whole is still clearly warmer than usual, Foreca meteorologist Joanna Rinne says in the weather blog.

According to the monthly forecast, the average temperature in Finland is up to 4–6 degrees warmer than usual. Temperatures of 20–24 degrees are predicted for the southern and central parts of the country at the beginning of the week, and 16–21 degrees for the north.

– By the end of the week, it will probably be 16–23 degrees in the southern and central parts of the country, and 15 degrees on both sides in Lapland, says Rinne.

In a large part of the country, according to the monthly forecast, rain will either be the usual amount for the time or in some places slightly less than usual. In the western and northern parts of the country, it is rainier than average in some places.

In the third week of September, the weather is still warmer than usual.

– Although the strongest high pressure has already moved further east over Finland, the week is still warmer than usual and the amount of precipitation is usual.

The monthly forecast shows signs of warmer-than-average weather also for the end of September and the beginning of October.

– Based on the monthly forecast, warmer than usual weather will continue for us in the weeks starting on September 23 and 30, at least in the weekly average temperatures.

Rainfall is pretty close to normal. At the end of October, Finland tends to be rainier than usual.

The weather in the first week of September is expected to be record hot and summery. There may even be several hot days during the week and it is possible that records will be broken. Temperatures can rise up to 25–28 degrees.

– High pressure is east of Finland and it turns the current to blow from the south. Thus, very warm air can flow from southern Europe to Finland, Foreca meteorologist Sara Salonen tells.

The hailstorms at the beginning of the week will decrease by Wednesday, when high pressure will strengthen from the east. Overall, the week’s weather is sunny throughout the country.

From Wednesday onwards, the week will even be hot.

– High pressure will keep the weather in a large part of the country still sunny on Saturday and Sunday, but individual rain showers are possible. During the day, the temperature is still between 20 degrees in the south and 15–20 degrees in Lapland.

Record broken?

If the forecasts are correct, Finland’s hottest day record will be broken this week. On Tuesday, September 3, this year’s 64th hot day was measured. Finland’s record for hot days is from 2002, when 65 hot days were measured in the country.

September heat is not an annual phenomenon, and on average autumn heat is measured less than one day somewhere in Finland. The last hot days in September were in 2019, even then there were three.

The September heat record was measured on September 6, 1968. At that time, temperatures of 28.8 degrees were measured in Rauma. Forecan Salonen thinks that the record limit can be exceeded, but it is unlikely to be broken.

This year there were a record 16 hot days in May. There were 14 hot days in June, 20 in July and 13 in August.

There is also a slight chance of large hail Friday afternoon and early evening, along with strong thunderstorms. Tiia Heiskanen

Thunderstorms can cause damage over the weekend, warns the Finnish Meteorological Institute.

In particular, the risk of urban flooding has clearly increased on Friday and Saturday.

On Friday, warm and humid air will arrive in Finland from the west, compared to the time of year.

At that time, thunderstorms occur in the western part of the country and in Northern Ostrobothnia. According to the Finnish Meteorological Institute, damages can be caused mostly by urban flooding caused by heavy rains.

There is also a slight chance of large hail Friday afternoon and early evening, along with strong thunderstorms.

Advice to the Venetians

A rainy weather front will move east during the night. The risk of urban flooding exists even at night.

– According to the forecast, the three-day rainfall from Friday to Sunday is 15 to 70 millimeters in a large part of the country. There are probably more thunderstorms with more rain in the southern half of the country than in the northern part of the country. In Lapland, the amount of rain will be less or even non-existent towards the north, writes a meteorologist in Foreca’s weather blog Joanna Rinne.

According to the Finnish Meteorological Institute, thunderstorms may occur during the day on Saturday in the vicinity of the eastern border, and they may also be accompanied by strong thunderstorms.

Slow-moving thunderstorms in the Southern Ostrobothnia region may cause urban flooding on Saturday.

– Those visiting Venetians should be prepared for Venetian conditions in some places, i.e. rubber boots are sometimes needed. Those who move outside should also regularly monitor weather warnings and weather radar during the weekend, advises the meteorologist on duty at the Finnish Meteorological Institute Pauli Jokinen in the bulletin.

On Sunday, the rain will intensify

According to Foreca, the rains will intensify on Sunday. According to Rinne, the heaviest rains fall in the western part of the country. There can also be thunder in some places.

– Sunday’s rain accumulation is 10–30 millimeters in a large part of the country, in the west it can rain even more in places. In Lapland, the rains will be less, a good 10 millimeters of precipitation will only occur in southern Eastern Lapland. In the rest of Lapland, there is little or no rain, Rinne says in the weather blog.

On Sunday, the wind from the north will be strong in the western sea areas.

According to Foreca, the daytime temperature on Sunday will mostly be 15 degrees, and during rain it will be 10–15 degrees. In sunny areas, between rains, it can be 15–18 degrees at its warmest.