Stockholm - Snösätra • 4 Oct 2020
overcast, rain, windy @ 06.00

Stockholm Arlanda Airport........13.6°C
Sthlm City........
13.6°C
Tullinge........13.6°C

The Mild Howl

 

Large Cyclone over Europe

Europe has been affected by a large cyclone for quite some time - and especially over Scandinavia we have been for at least a week or more, in a strange flow going from east to west. This type of weather pattern isn't that common (in my opinion) for end of September and beginning of October. I would mainly associate that kind of weather pattern (sometimes) and not so often, during brief periods in the end of Spring, or Beginning of Summer.

The present weather pattern is supported by a larger anti-cyclone over Russia, and it's counterpart, low pressure over West Europe, pumping cool air into Ireland, UK, France and Spain. This appears to repeat and regenerate even in the upcoming week as indicated in the GFS prognosis

Also interesting is, that the Russian anti-cyclone is of a warm character. Normally, in October it is more common that you would associate it with cold airmasses - but this time - the anti-cyclone has established a constant inflow of hot air via the Caspian Sea - and once it reached us, it turned into a more moderately warm airmass coming in from the east.

The problem for Stockholm is that this time of the year - End of September to Beginning of October - the sun is not as strong anymore. And being a mild airmass coming from the east and southeast, it goes over the Baltic Sea. Altogether means lots of clouds. Night fog has become more common, and sometimes the clouds did not dissolve during the day. Other days we got sunny weather, in the end of September.

Perhaps it is because this weather pattern established itself very early in the season, that it turned out both warm (instead of chilly or cold), and even allowed us to get some sun after all - with temperatures up to 18-19° (despite the air flowing over a larger Sea before entering our realm)

 

Very High minimum temperatures in Scandinavia

As of lately however the clouds have dominated - so the MAX temperatures have been lower, around 14-15°C, (albeit 18° two days ago, on 2 Oct 2020) but the MIN temperatures are really VERY MILD not going below 10-13°C. (Average Normal MIN for Stockholm, 4 Oct 1961-90 is +6.7°C, low in the outer suburbs) In the past 24 hours it's been basically all around 14° constantly.

 

20-23°C in (some) Norwegian Fjords

Another effect the flow of mild air from the east towards the west has been, that in some of the Norwegian fjords, you got unusual high temperatures (due to Föhn winds), with temperatures between 20-23°C !

 

662 mm Rain in the Alps (1.5 days)

The large cyclone "BRIGITTE" over France, it's meandering as well regenerating into new cores - had created a very strong southern-southwestern airflow coming from the Gulf of Genoa pulling heavy laden clouds into Piedmont (Torino, Milano, Bergamo) and then getting stuck in the Alps - with extreme rainfalls.

This is a common phenomena in autumn - sometimes it hits the French Riviera, and often the Italian side with Genoa, or sometimes the Southern side of the Alps over North Italy and Switzerland. Absolutely mindboggling amounts of rain that get "stuck" there... like Aosta Valley and the Alps on the border to Switzerland.

During the time of 2 October until afternoon 3 October 2020, the Italian station Verbano-Cusio-Ossola registered 662mm rain. With devastating flash flooding in the whole area, ripped of bridges and streets. Torino/Turin got away with 60 mm rain during the same time. However, more rain has fallen since the numbers below ! And more is predicted to fall.


620 mm in Mergozzo
610 mm in Piedicavallo
552 mm in Fobello
495 mm in Oropa
452 mm to Camparient Refuge
439 mm in Mottarone
438 mm in Fomarco
423 mm in Cicogna di Cossogno
414 mm in Boccioleto

 

Hot Scirocco winds over Sicily

Yesterday temperatures over West Sicily, Italy as well along the north cost below the hill sides, very high temperatures up to 38°C were registered. And in the afternoon, it then dropped like a stone, at least by 10-12°C within minutes, starting first at the Airport of Palermo, and then an hour later reaching the city, going down to 24°C. While Stations like Milazzo and Vulcano had 36°C, just a few miles to the west, the temperatures was "only" 26°C, and Messina just 24°C.

This effect did not impact much Catania, which had temperatures around 24-25°C during the day.

 


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