Temperatures drop throughout Finland as rain and snow arrives

The cold change that was due to hit Finland arrived late on Sunday night. The change had been predicted since as early as the start of last week and the arrival of northerly winds for the first time in quite a while led to sharp temperature drops throughout the country. Rain and even snow has been seen in the south also.

Jyväskylä saw temperatures hold steady around 10C in the early hours of September 22, but the tripling of wind speed between 4am and 5am saw it drop to around 5C by 8am. While temperatures at this level at that time of the day have been seen in the recent weeks, it was what happened in the following hours that was different, as the graph below shows.

Temperature readings at Jyväskylä Airport from 3pm September 21 until 2:30pm September 23
Source: Finnish Meteorological Institute

In contrast to earlier this September, and actually not since June, temperatures failed to climb during the day. They only dropped further and it was below 4C by 3pm. 

With a maximum of only 3.0C, today was the coldest September day at least in the years since 2009. This is more than 2C lower than the previous lowest. The coldest September day since 2009 had been recorded last year on the 25th. It only reached as high as 5.3C then. The 29th and 30th of 2013 managed tops of 5.4C. Of the other four years (2009-2012), the lowest maximum was 7.2C in 2012, coincidentally recorded also on September 25.

Jyväskylä's chance at recording its driest September on record was quickly washed away in the three hours between 11pm Sunday and 2am Monday. Up until 10pm on September 21, only 1.7mm had been recorded at Tikkakoski since the start of the month. Those three hours, however, accounted for 10.7mm, leaving the all time record of 8.8mm from 1901 safe for now.

Yesterday afternoon saw fairly consistent measurements of just under 1mm per hour from 2pm to 7pm. That led to a total of 13.2mm yesterday, pushing the monthly total to 16.9mm. The 1981-2010 average of 38mm still seems a fair way off, but more rain is forecast later this week.

Jyväskylä also managed to avoid most of the precipitation associated with a trough that had been slowly moving east across Southern Finland. Precipitation mostly fell as rain in Jyväskylä centre during last night and early this morning, but some nearby locations reported snow. Jyväskylä's ski centre, Laajavuori, received some snow this morning as the picture below shows.

Snow on Laajavuori just before 8am on September 23

Eastern Finland, especially, saw heavier snowfall. Temperatures there hovered closer to 0C. Ilomantsi, close to the Russian border, reported a snow depth this evening of 9cm. Meanwhile in nearby Joensuu, the reading was 3cm. Jyväskylä centre received some wet snow from the middle of the afternoon today all the way into the late evening, but the moist and above 0C air meant that any that reached the ground immediately melted.

Wet snow falling in Jyväskylä's Viitaniemi during the afternoon of September 23

More wet snow is expected tonight and temperatures tomorrow shouldn't climb higher than 6C or 7C.