Accuweather already came with the Autumn 2021 forecast, which expects early autumn snowfall across the continent, mainly in regions strongly influenced by stormtrack positions thanks to La Nina.
Moreover, above-average Hurricane season 2021 is still expected, which should mean more Arctic air on both sides of the Northern Atlantic, which will be pulled from the Arctic in a direction into the middle of deep pressure systems.
There are long-term signals, that AO- and NAO- phases will be more frequently such as usual, which should mean together with expected La Nina, strong hurricane season or QBO- early cold blasts already in September, October, and November 2021.
Early cold blasts should in many regions bring earlier the first snowing and large snowfalls during the next months, such is usual in Europe, North America, Asia, or even North Africa.
The situation should be similar, or a little less extreme such as in Autumn 2021 – mainly the end of September 2020 and October 2020, when winter season blasts came very early and parts of Europe, USA, Canada or Asia reported historic frosts or snowfalls /see our archive from October 2020/.
Colder autumns in the Euro-Atlantic region are often associated with changes of circulation – mainly the effect of melting the Arctic to Gulf Stream and regional stormtrack trajectory, which is usually anomalously shifted more southward, with the result of more frequent AO- and NAO- phases after 2000.
Exceptions such as Autumn 2018, when persisted above Europe sunny and very hot/warm weather however aren´t totally fully excluded.
The year 2021, thanks to the above-mentioned factors, however, very probably won´t surprise and the next colder, more rainy, cloudy, and prematurely snowy autumn in many mid-latitudes is the most probable.