Europe on the long term 16th December

Here is the latest European outlook for snowfall prospects on the long term.

1st-5th January

In this period, EC Monthly shows troughing over the Alps and Southern Europe, with Scandinavian ridging/-NAO present. Warmer than normal for parts of Western Europe, and colder than normal for Eastern Europe.

6th-10th January

Troughing anomalies over Far Eastern Europe and off the Atlantic Coast of the British Isles, along with a Scandinavian high are present for this period on EC Monthly. Warmer than normal for Southeastern Europe. CFS is forecasting European ridging for this period.

11th-15th January

Scandinavian ridging and North African ridging are reducing troughing risks for Southern Europe, and increases it for Northeastern Europe on EC Monthly. Cooler than normal for parts of Eastern Europe. Wetter than normal for Southeastern Europe. CFS still forecasts European ridging to continue, but troughing develops towards Southeastern Europe.

16th-20th January

Ridging over Spain reduces snowfall over the Alps, and creates a zonal pattern over the UK, per EC Monthly. Warmer than normal for Western Europe including the Western Alps and the UK. Wetter than normal for the UK.

21st-25th January

Ridging over Southern Europe on EC Monthly reduces snowfall for the Alps, particularly for the South. A low in Scandinavia ensures a zonal pattern for Northern Europe. Warmer than normal for Southern Europe and the Alps, neutral for the UK. CFS forecasts more European ridging and a zonal pattern for UK.

Arctic Oscillation

The AO/NAO are both negative in the medium term per EPS Monthly, until the New Year. The impacts of this should continue into the first week of January, before a return to more zonal conditions.

GWO

A positive mountain torque is expected over the next few days worldwide, with the East Asian component lasting a few days and quickly heading back to negative. This is probably enough to dampen the fall of the GLAAM and head us through Phase 2 & 3 in the GWO over the next fortnight, eventually landing us in Phase 4 again as we enter the New Year.

If we take the composites:

We see a -NAO setup develop in GWO Phase 1 with a lag. This spawns a good couple of weeks for the Southern Alps IMO, with meridional setups created by the GSDM. In Phase 3 & 4, we start to see this breakdown into a more zonal pattern in the Atlantic, which is preceded by the development of a European High, particularly for the North. So I’d argue for a -NAO being present for much of the next two weeks, based on the factors that run through the GSDM. This -NAO will continue into the New Year for a little bit, but should start to wind down as the GLAAM heads into the more positive momentum orbits.

This means more cold and snowfall for the UK, even though the NAO’s alignment in this case is crucial and may weaken cold risks for the UK.

This also means a case for good snowfall for the Southern Alps, and probably less so for the Northern Alps. The rest of Southern Europe should benefit from this.

MJO

GEFS continues the consistent IO focused base state, but shows some signs of convection around the Atlantic over the next week.

EPS forecasts the IO base state to strengthen over the 10 day period, and then weaken in the last week of December. This allows the Western Pacific to take control more so, within the pattern.

EPS shows some signs of the forecast heading towards a Phase 6 in the MJO for the New Year, after RMM prescribed neutrality in the next two weeks. This would contribute to a -NAO potentially, but also add to momentum that would diminish the -GLAAM base state.

Stratosphere

All this talk of meridional anomalies is likely to be dampened after the next week or so, by the downwelling strong SPV anomalies moving down into the troposphere. When it precisely does manage to weaken the -NAM is unclear, but it’s likely to occur from the last week of Dec or perhaps the first week of January next year. When it does the EPS Monthly forecast used in the models section of the blog is more likely to manifest, with the drivers influencing a relaxation of any cold risks for mid-January.

Conclusions

  • Fair to say that the next two-three weeks are likely to feature some potential for cold and snowfall risks for the UK and Southern Europe. This doesn’t mean snowfall is necessarily imminent for the UK, just that potential is enhanced. This effect may be stronger for Southern Europe, as opposed to the UK, as the anomalies lack a lot of strength.
  • This is generated by the -GLAAM state going through a low orbit of the GWO and the current -AO and -NAO state.
  • This period is likely to end around the first week of January, when a more zonal pattern takes root for the middle section of January. This would favour snowfall for the Northern Alps.
  • A potential next period for -NAO and -AO risks would be early in February, maybe.

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. 

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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