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Space weather forecast: Aurora light show possible as far as southern Finland

Discharges through an opening in the sun's corona could trigger a Northern Lights display over Finland this weekend.

Image: Jussi Lindroos / Yle

Meteorologists have said that there is a high possibility for skywatchers to witness a display of Aurora Borealis or Northern Lights on Saturday or Sunday night.

The event is caused by a rapid electromagnetic discharge from an opening in the Sun’s corona towards the earth. According to forecasts by the Finnish Meteorological Institute FMI, the speed of the discharge could exceed 700 kilometres per second and could trigger a minor magnetic storm.

"Things are happening in space! In the nights ahead it’s possible that we will see Northern Lights in our skies," FMI tweeted on Saturday afternoon.

It added that if the storm is even a bit more powerful, then the phenomenon known as Aurora Borealis could be visible as far as southern Finland around midnight on Saturday.

FMI: Uncertainty over timing

FMI said the biggest uncertainty about its space weather forecast is in the timing. "If the impact of the opening in the corona is the same as last time [on 5 August] it will begin in Sunday, in which case the Northern Lights show will begin Sunday night," the agency said on its website.

"However the opening has expanded since the last time so this time the discharge could arrive earlier, in other words on Saturday night," it added, advising the public to monitor the situation from Saturday evening.

"If nothing happens then, you should check again on Sunday night," FMI continued. It’s also possible to follow the agency’s online space weather forecast in English (siirryt toiseen palveluun), however the Finnish-language service provides more information (siirryt toiseen palveluun).

"In terms of [expected] cloud cover there is a good chance to see the Northern Lights, at least in southern and central Finland. It will be cloudier in the north, but there could be breaks in the clouds in some areas," said Yle meteorologist Joonas Koskela.

According to the latest weather forecast, skies will be clearer on Sunday night.