Material from: Linus, Ervin
1. Overview
In the beginning of January 2026 large parts of Europe was under a cold spell and snowfall. The most extreme temperature anomalies were in Northern Finland and Sweden.
2. Analyses and Observations
2.1 Event Definition
Here we will focus on the 3-day mean 2-metre temperature 8-10 January in a box over mainly northern Finland (66N-68.5N, 22E-30E)..
2.2 Analyses
The plots below show analyses of z500 and T850 for the period 2 January to 11 January.
2.3 Observations
2.4 Climatological perspective
The plot below shows the 2-metre temperature anomaly for the week 5-11 January.
The plot below shows the time-series of daily mean 2-metre temperature inside the box over northern Finland for daily values (thin), 7-day running mean (thick) and climatology (dashed)).
3. Forecasts
3.1 Data assimilation and observation usage
The plot below shows the statistics for analysis and background departures for 2-metre temperature observations inside the box.
3.2 Single Forecasts for the event based on 00UTC forecasts (defined in Section 2.1)
Observations and analysis for the event
Control forecast (IFS 9-km resolution)
DestinE (IFS 4.4km resolution)
AIFS-single (AIFSv1.0 ~0.25 resolution)
AIFS-CRPS ensemble (~0.25 degree resolution)
3.3 Ensemble distribution
EFI (based on IFS 9-km ensemble)
The plots below show EFI for 2-metre temperature valid 8-10 January.
Forecast Evolution plot
The plot below shows the forecast evolution for 2-metre temperature on 8-10 January for the box over northern Finland.
The plot shows the same as above but for sub-seasonal forecasts.
3.4 Sub-seasonal forecasts
The plots below show forecasts of weekly temperature anomalies for 5-11 January.
The plots below show the same as above but for z500.
3.5 Comparison with other centres
4. Hazard Forecasts
5. Dedicated Experiments
6. Event Summary
6.1 Good and bad aspects of the forecasts for the event
- Well predicted magnitude of the cold in the short-range forecasts
- Signal for cold started to appear from 27 December.