Winter weather 2017/18
The UK winter 2017/18 forecast headline is for a colder and drier than average season. The coldest periods are expected in December and January with mild spells becoming more frequent by February. The risk of widespread and potentially disruptive snowfall is considered to be higher than in any winter since 2012/13. However things appear to be quite finely balanced and a milder outcome is considered only slightly less probable.
The forecast was produced by looking at a number of factors, including:
- Seasonal forecast models
- Persistence patterns during recent seasons and historical analogues
- ENSO conditions
- Quasi-Biennial Oscillation (QBO)
- Atlantic sea surface temperatures (ssts)
- Solar activity
- Autumnal weather patterns and the development of snow cover in Siberia
Forecast confidence levels for this winter are again very low. A number of indicators such as the weak La Nina, low solar activity and the negative QBO all suggest an increased chance of colder periods. The weather patterns during September, October and November are also thought to favour a cold winter. Nonetheless seasonal computer models still suggest a positive negative North Atlantic Oscillation pressure pattern for much of the season and the likelihood of a milder and wetter winter.
In conclusion the TWO view is December and January bring an elevated risk of disruptive snowfall and cold weather.