Here on the blog we are going to look at some long term modelling and then the climate drivers…
We see an Atlantic ridge present and a strong Ural ridge, with a low in Southern Europe, bringing down cold air over the UK and Southern Europe
We still see the remnants of the Southern European low, but it’s weakening in favour of a European ridge downstream from the Atlantic high. We also see a strong polar vortex develop from the north.
We see a strong Scandinavian low drive mild and wet conditions for the UK and Northern Europe. On the opposite, we see a ridge develop over the European continent weakening snowfall over the Alps.
We see a mild outlook for the UK and Scandinavia driven by a +NAO/+AO. The rest of the continent is occupied by a strong ridge leaving dry conditions.
We see a +NAO driven outlook for a mild UK again, and ridging growing over Europe.
We see the same, a mild +NAO driven outlook for the UK and a ridge for the rest of the continent.
To buck the trend of the modelling above, a colder and snowier outlook for the UK and the Southern Alps/Europe seems to have arrived on the climate driver beat.
A sudden stratospheric warming is a strong weakening of the polar vortex in the stratosphere, which enables a negative Arctic Oscillation that helps to bring snowfall and cold for the UK and Southern Europe/Alps.
The chart above shows the extraordinary displacement of the polar vortex that is likely to help bring forth colder effects for Europe and bring a snowier outlook for the first 3-4 weeks of the new year of 2021 for Europe and the UK.
- From now to the 27th, we expect a -EAMT to come and weaken the North Pacific jet, that helps to push around the NH climate circulation a more +NAO look.
- Then we see a push towards a more -AO and the weakening of the stratospheric polar vortex with a strong +EAMT from the 27th to at least the 4th of January. This should combine with the stratospheric disturbance for a -NAO and -AO look from the 2nd and 3rd weeks of January as it comes around from the North Pacific.
For now the MJO is neutral for the next few weeks, so won’t affect the weather over Europe much.
But it is clear from the prognosis for the negative AO and the weakening of the stratospheric polar vortex, as well as the recent and future bouts of +EAMTs keeping the AAM relatively high, we may see some cold and snowfall for much of Europe in the first three weeks of January, particularly of interest for the UK and Southern Europe/Alps.
Thanks so much for reading. I hoped you enjoyed reading it.
Disclaimer: There is lower skill asssociated with using long range model forecasts to find snow systems.
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