Europe on the long term 28th Dec

Models

8-9 Jan

GFS shows a Front coming from the North, into the Northern Alps early on the 8th with heavy snowfall in the back.

11-14 Jan

A low on EC Monthly starts late in the 11th of Jan, coming in from the Southern Alps with moderate-heavy snowfall, dragging along the Southern region until the 14th, easing over the 14th. The most recent run shows it more like rainfall at lower mountain regions.

14-17 Jan

Just hours after the last one left, another system comes from the North and brings moderate-heavy snowfall across much of the Alps. The snowfall starts to send the snowfall on the South and the East on the 17th, and ease.

19-21 Jan

Another low on EC Monthly comes along the Southern Alps on the 19th, with moderate-heavy snowfall. By the 21st, the snowfall is heaviest in the Eastern Alps. The brand new EC Monthly run (not linked) likes the 21-23 Jan period.

EC Monthly

The general latest modelling likes more snowfall and troughing for the Alps from roughly the 7th of Jan, until at least the 21st of Jan.

Climate Drivers

  • A positive East Asian Mountain Torque is currently occurring, which helps speed up the North Pacific jetstream. This increases global +MT, and with a 3-5 day lag, creates a +AAM. I expect a peak in +AAM during the first week of January. The corresponding GWO Phases 6 & 7 support a more -NAO like outlook in the weeks succeeding the peak, along with influence from the Stratosphere.
  • The AAM (Atmospheric Angular Momentum), while being positive for the first two weeks of January roughly, should go negative late in Week 3 and Week 4 of January, creating the way for a less favourable Early February, in accordance with the waning impact of the SSW.
  • The MJO GEFS forecast is heading for a Phase 5-6-7-8 orbit over the first two-three weeks of January, with a very amplified MJO signal forecast. Meanwhile EPS is heading for the weak circle in the next few days. I believe because of the way the extratropical components are laid out, I think the more amplified MJO is a more plausible forecast. Phase 6 & 7 support a -NAO regime with a 10 day lag.
  • We currently have a SSW occurring, with a weakening of the SPV expected to reverse the winds at 10hPa 60N. GEPS and GEFS show a near disintegration of the polar vortex in the stratosphere, with a minor split of a smaller part of the PV. EC (below) is the closest to a genuine split of PV, but it isn’t quite there. I think we will see a very weak SPV, off the bat of a continued wave 1 attack, that lacks the means to fully split the PV. The vortex looks to probably be dislodged over Scandinavia, which brings more cold into the region of Europe, but also more zonal winds. But given we should see a -NAO develop in the first and second weeks of January, this impact should be negated. In the latter three weeks of January, the SSW given a lag, will have a colder influence of Europe.
  • The overall impact of the SSW, and extratropical/tropical factors is a favourable Week 2-4 of January in Europe, and relaxation of the favourable pattern in Early Feb. Overall there will be more cold for the UK and the Southern Alps. It may be less snowy for the Northern Alps, than the South, but they still should get a decent amount of snowfall.

Thanks so much for reading. I hoped you enjoyed reading it.

Disclaimer: There is low skill asssociated with using (slightly outdated, sorry!) long range model forecasts to find snow systems.

Thanks again for reading this European long range snow forecast, follow me on Twitter @longrangesnow and subscribe to my email list by clicking on the tab on the main header above.

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