On October 8, 2020, DTN SVP & Industry Principal Weather Mike Eilts hosted a special webinar to help European energy trading organizations better understand, prepare for, and manage their winter risks for the upcoming season.
Eilts was joined by DTN Senior Energy Meteorologist Matthew Dobson and Prescient Weather Ltd/World Climate Service CEO Jan Dutton, who provided a preliminary forecast for the 2020-2021 winter season. They also discussed the previous year’s forecast performance and the benefits of model calibration in creating weather outlooks.
Here are some of the hightlights:
Was winter 2019-20 predictable?
It was a victory for numerical weather prediction (NWP) seasonal models. Several marked sea surface temperature (SST) anomaly patterns were evident during Autumn 2019. Notable events included:
- A weak/central Pacific El Niño
- Extensive, very warm north Pacific SSTs — aka “The Warm Blob”
- A record strength, positive Indian Ocean Dipole (IOD)
What to expect this winter in Europe
October-December 2020 summary | Confidence: medium to low
- The early October pattern has been cold in the west, but also very wet and windy. Drier and calmer in the northeast.
- High pressure over the northeast Atlantic rather than over Scandinavia should come to dominate.
- Further cold northerly plunges across western Europe, especially during November. Warmer over far southern and far northern Europe.
- Dry anomalies could develop more frequently in November and December over the west/southwest. Windy in Germany and Italy.
- Often wet across the southern Alps and especially southeastern Europe. Westerly flow into the north and northwestern Nordics will increase.
- NWP guidance suggests a warmer and wetter northern Europe in December. There could be a higher chance of negative North Atlantic Oscillation (NAO) patterns in December than in recent years, especially if the Polar Vortex doesn’t become strong in late November and December.
December 2020-February 2021 summary | Confidence: medium to low
- Notable contradictions in the current guidance (both NWP and statistical) mean low confidence for the northern half of Europe.
- Greatest confidence for a cold winter is over France, northern Spain, the western Alps, and eastern Europe.
- Cold over the United Kingdom (UK) and Germany in early winter; less of a feature later in winter as a positive NAO develops. This is due to the expected La Niña being at least moderate in strength, rather than just a weak event.
- Overall, the UK will be less wet and stormy than during winter 2019-2020. Germany and Italy will see intermittent windy northwesterly episodes.
- There is a 25% risk that NWP model predictions (especially CFSv2 and UKMO) will prevail with a milder westerly pattern.
- There is a 20% risk that early winter blocking patterns will persist or return at times, so conditions could be widely colder, drier, and calmer in northern Europe.