Material from: Linus
1. Overview
In the end of April 2025 Western Europe experienced unseasonally high temperatures.
2. Analyses and Observations
2.1 Event Definition
Currently based on the 2-metre temperature for Reading (51.5, 1W) on 30 April 12UTC. An evolution plot is also available for the 3-day mean temperature (29 April -1 May) for a 0.25x0.25 degree box centred on London-Heathrow (51.5N, 0.5W).
2.2 Analyses
The plots below show analyses of T850 and z500 from 26 April to 2 May.
2.3 Observations
2.4 Climatological perspective
3. Forecasts
3.1 Data assimilation and observation usage
3.2 Single Forecasts for the event based on 00UTC forecasts (defined in Section 2.1)
Observations for the event
ECMWF analysis
Control forecast (IFS 9-km resolution)
Compared to the ECMWF analysis, one can note the colder temperatures over France.
DestinE (IFS 4.4km resolution)
AIFS -single (AIFSv1.0 ~0.25 resolution)
The warm temperatures over France is better captured in AIFS.
AIFS ensemble (AIFS diffusion ensemble ~1 degree resolution)
3.3 Ensemble distribution
EFI (based on IFS 9-km ensemble)
The plots below shows the EFI for 3-day mean temperature 29 April 1 May. The event was well captured at least from 24 April and onwads.
Forecast Evolution plot
The plot below shows the evolution plot for the 2-metre temperature on 30 April 12UTC for Reading. The prediction was extremely good from AIFS-single.
Legend:
Observation - green hourglass
Analysis - green dot
ENS CF - red dot
DestinE - dark-green dot
AIFS-single - cyan dot
ENS distribution - blue
AIFS-ENS-CRPS distribution - pink
ENS m-climate - cyan
ENS m-climate maximum - black triangle
The plot below shows the evolution plot for 3-day mean temperature for London-Heathrow (see event definition). Same legend as above.
3.4 Sub-seasonal forecasts
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
- Extremely good prediction by AIFS-Single more than 7 days in advance
- Good predictability for the event overall
- Too cold temperatures in IFS over France