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Created by
Linus Magnusson, last updated on Oct 28, 2026
6 minute read
Material from: Linus
1. Overview
During 5–6 June 2026, Esperanza station recorded maximum temperatures of 15.4°C and 13.4°C, respectively. Both values exceeded the previous June record of 13.3°C, set on 12 June 1998. The 1991–2020 daily maximum temperature normal for Esperanza in June is around −6.2°C, so this was an extremely anomalous event (from Paola Rodriguez Imazio).
2. Analyses and Observations
2.1 Event Definition
Here we will focus on 3-day mean temperature on 5-7 June for the Esperanza station (63.4S, 57.0W).
2.2 Analyses
Link to Weather Replay:
The plots below show analyses of MSLP and 6 hour rainfall from 3 June 00UTC to 8 June 00UTC, every 12th hour.
The plots below show analyses of z500 and T850 from 30 May to 8 June, every 24 hour.
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 and analysis for the event
In the analysis and IFS control forecasts one can large variability in the temperature on the eastern side of the peninsula, probably due to the Fohn effect. The point picked up for Esperanza is not particularly warm.
Control forecast (IFS 9-km resolution)
The plot below shows time-series of IFS control forecast from 5 June and the observations from Esperanza. We can see a significant cold error in the forecasts, but looking at the plots above we see that nearby gridpoints were warmer.
DestinE (IFS 4.4km resolution)
AIFS-single (AIFSv1.0 ~0.25 resolution)
AIFS-ENS control (~0.25 degree resolution)
3.3 Ensemble distribution
EFI (based on IFS 9-km ensemble)
The plots below show the Extreme Forecast Index for 3-day mean temperature valid 5-7 June. There was an early signal for this large-scale warm event.
The plots below show the Extreme Forecast Index for 3-day mean integrated water vapour flux valid 5-7 June. Also the moisture flux anomaly was well predicted and contributed to the Fohn effect.
Forecast Evolution plot
The evolution plot below shows the mean 3-day 2-metre temperature valid 5-7 June for Esperanza for different ECMWF medium-range forecasts. Already 15-day forecasts indicated a strong warm anomaly, but one have to be careful with the interpretation of the model climatology here.
The plot below shows the same as above but for the sub-seasonal forecasts. The signal appeared around 19 May, that is more than two weeks before the event.
3.4 Sub-seasonal forecasts
The figures below show verification plots of 2-metre temperature anomalies for the week 1-7 June. Also here the very early signal for the warm event can been seen.
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
- Very early signal for the event (more than two weeks before)
- The short-range forecasts had a cold error, probably due to underestimating the Fohn effect and/or local variations in the temperature.