Status:Ongoing analysis Material from: Linus, Ervin, Rebecca
1. Impact
During July 2024 south-eastern Europe (Hungary, Serbia, Romania and other) was hit by an exceptionally long heatwave.
The event was covered in this ECMWF Newsletter article: https://www.ecmwf.int/en/newsletter/181/news/extremely-warm-summer-southeast-europe
2. Description of the event
The evaluation of this event will focus on a 5-day period (13-17 July) for a region covering the Danube plain from Hungary to Serbia (44N-47N, 19E-22E)
The plots below show analyses of T850 and z500 from 10 July to 20 July.
The plot below show daily mean (based on 00 and 12UTC) temperature over the Danube plain based on ERA5. Daily values (thin), 7-day running mean (thick) and daily climatology (dashed).
The plot below shows the analysis of 5-day temperature for 13-17 July.
Heat stress
On 18 July 2024, the average feels-like temperature (UTCI) across southeastern Europe (land only) reached 38.02°C. 38°C is the threshold for 'very strong heat stress'. The maximum value in ERA5-HEAT, averaged over southeastern Europe, is 39.37°C, on 24 July 2007.
On 17 July 2024, virtually all (98%) of southeastern Europe was affected by at least 'strong heat stress', i.e. a feels-like temperature exceeding 32°C. On 18 July, 52% of southeastern Europe was affected by at least 'very strong' heat stress (feels-like temperature exceeding 38°C).
Again on 13 August 2024, virtually all (99%) of the region was affected by at least 'strong heat stress', and on the same day 53% of the region was affected by at least 'very strong' heat stress.
3. Predictability
3.1 Data assimilation
3.2 HRES
3.3 ENS
The plots below show EFI for 5-day temperature 13-17 July.
The plot below shows the forecast evolution for the 5-day temperature 13-17 July for the box outlined above.
Analysis - green dot
SUBS ensemble - red
SUBS m-climate - pink
3.4 Monthly forecasts
The plots below show forecasts of weekly temperature anomalies for 8-14 July.
The plots below show forecasts of weekly z500 anomalies for 8-14 July.
The plots below show forecasts of weekly temperature anomalies for 15-21 July.
The plots below show forecasts of weekly z500 anomalies for 15-21 July.
The plot below shows weekly ensemble-mean average temperature for the event box for different forecast lengths including ERA5 analysis.
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Problematic SUBS forecast around 26 June, predicting a cold anomaly 8-14 July