New study: More (very) large hail in most of Europe

A new study by ESSL, Adam Mickiewicz University, NSSL, and the Freie Universität Berlin, lead-authored by ESSL researcher Francesco Battaglioli, has been published in the AMS Journal of Applied Meteorology and Climatology

In the study, entitled “Modelled Multidecadal Trend of Lightning and (Very) Large Hail in Europe and North America (1950-2021)” they reconstructed the climatology of lightning and (very) large hail in Europe and North America since 1950 using statistical models (AR-CHaMo) trained with about 24 million lightning observations and more than 44000 hail reports.

Left: Mean modeled annual and seasonal number of hours with hail of 5 cm or larger in a 0.25 x 0.25° box.
Right: Change in the annual number of hours with very large hail per decade. Significant trends (p<0.05) are hatched.

They found that, across Europe, large (≥ 2 cm) and very large (≥ 5 cm) hail is most common across northern Italy, south-western France, and eastern Spain. Hail frequency has increased across large parts of Europe. This increase is caused by rising humidity in the lowest layers of the atmosphere.

Left: Mean modeled annual and seasonal number of hours with hail in a 0.25 x 0.25° box.
Right: Change in the annual number of hours with hail per decade. Significant trends (p<0.05) are hatched.

In North America, hail is most common across the U.S. Great Plains. Unlike Europe, the modelled hail frequency has only increased in certain areas, while it decreased in others. Areas with increasing hail include the High Plains of Colorado and Central Canada.

Modelled time series of hail across Northern Italy and Central Oklahoma.

Focusing on two hail-prone areas, northern Italy and central Oklahoma, temporal changes in large hail frequency can be shown using “Hail Stripes”, much like those used to illustrate temperature changes, first by Ed Hawkins. These stripes show that, across northern Italy, very large hail is now 3 times more likely than it was in the 1950s.

Modeled seasonal cycles of large and very large hail for three different periods (1950–73,
1974–97, 1998–2021).

Since 1950, the season in which large hail occurs has lengthened across Northern Italy, especially because of an earlier start in Spring.     

Experimental lightning and hail forecasts, with hail observations overlaid,
based on AR-CHaMo, available at

The AR-CHaMo models also have important applications in hail forecasting and are used for experimental real-time forecasts available at the website The so-called Convective Available Potential Energy, a parameter often used by forecasters, was shown to be of limited value. Instead, the part of this potential energy released high in the storm cloud at temperatures below -10 °C was found to be a much better predictor for large hail.

This work was funded by the German Ministry of Research and Education (BMBF) within the project CHECC, part of the ClimXtreme Research Programme. has been developed in the Project PreCAST supported by the Austrian Science Fund (FWF) and the European Centre for Medium-Range Weather Forecasts (ECMWF).

ESSL welcomes Météo-France as a new Full Institutional Member

In June 2023, Méteo-France has become a member of the European Severe Storms Laboratory. This means that they have joined the present 25 Institutional Members of ESSL: public or non-profit organizations in Europe active in the realm of weather and climate forecasting or related fields. The ESSL Team extends a warm welcome to Météo-France, which will now have full access to the European Severe Weather Database to support its activities. In addition, full ESSL members have a vote in ESSL’s General Assembly and benefit from reduced participation rates in ESSL activities. ESSL is looking forward to the cooperation with Météo-France.

Online mini-ECSS 2022

The European Severe Storms Laboratory calls for contributions to the mini-European Conference on Severe Storms (mini ECSS) to be held on 27 and 28 September 2022 via the online conferencing tool BlueJeans.

The pandemic situation over the past years has led to the postponement of the European Severe Storms Conference for spring 2023.

The mini ECSS, a prequel to the ECSS 2023 (Bucharest, Romania), offers an opportunity for PhD students and early-career scientists to present their latest research. This event is structured such that, for each day, there will be 10 presentations (each 15 min long) in the morning followed by 2 invited lectures (each 40 min long) in the afternoon.

Register here for the event or to submit an abstract for presentation.
Those who submit an abstract are asked to provide us with a short biography.

New ESSL–EUMETSAT partnership on using next-generation satellite data in severe convective storm forecasting

ESSL is delighted to announce that it has entered into a contract with EUMETSAT for three years to train forecasters of the national (hydro-)meteorological services of its member states. The training focuses on the use of products from the next-generation satellite missions Meteosat Third Generation (MTG) and EUMETSAT Polar System–Second Generation (EPS-SG) for the analysis and nowcasting of severe convective storms.

EUMETSAT and ESSL have started this contract on 1 June 2021 that is intended to pave the way for longer-term collaboration in support of the European meteorological community.

ESSL will organize training testbeds for operational forecasters of Europe’s weather services, introducing proxy, and later real, data from EUMETSAT’s next-generation missions with a focus on severe convective storm forecasting. The aim is to totally train about 10–15% of the operational meteorological workforce in European weather services, or about 200–300 forecasters.

The testbeds will mainly be organized at ESSL’s Research and Training Centre in Wiener Neustadt (Austria), but can also be hosted by weather services with suitable facilities upon their request. Optionally, testbeds can be held online as well.

Besides the testbeds, expert workshops will be organized for a small number of people that include senior forecasters, product experts, senior trainers, science-to-operations staff, and experts from EUMETSAT. The aim of these workshops is to better understand novel capabilities for severe storm analysis and prediction, such as with the new 0.9 mm and 2.25 mm bands, the Lightning Imager, and the Infrared Sounder, and to develop training concepts and material. The first such workshop will be planned during the first months of 2022.

Job vacancy: Researcher (closed)

Click here for a printer-friendly pdf document.

The European Severe Storms Laboratory (ESSL, is looking for a

Researcher (75 – 100 %)
for two years initially

based in Germany, to support its work in the research project CHECC on severe thunderstorms and climate change (see below) at 75% of a full position.

Optionally, other tasks involving programming work in support of the ESSL Testbeds may be taken over. In this case, the researcher can be hired full-time. We are looking for someone who can start in the coming months, or at the latest by September 2021.


We are looking for support of the project “Convective Hazard Evolution under Climate Change” (CHECC, see:, part of the German research programme ClimXtreme (see: which includes several research groups at various universities. The primary goal of CHECC is to find out if effects of climate change on the occurrence of (severe) thunderstorms in Europe can be detected in reanalyses and climate models. This is done by developing and applying statistical methods with a strong basis in physics. Tasks of the researcher will include:

  • Evaluating the role of changes in synoptic scale weather patterns on severe thunderstorm probability
  • Evaluating changes in the variability of weather conditions supportive of severe thunderstorms
  • Reporting on the research in peer-reviewed scientific journals

ESSL Testbed

The ESSL Testbed is a collection of one-week events, which (in non-corona times) takes place in person at ESSL premises in Wiener Neustadt, Austria. There, forecasters and developers work together to evaluate novel products developed to support the forecasting and warning process. They do this by using these products based on satellite, radar, and numerical weather prediction data to make forecasts in a quasi-operational setting. ESSL seeks someone to help develop and maintain the ESSL Weather Data Displayer, which is an interactive web page for displaying meteorological data.


The employee needs to be a resident in or moving to Germany as this is a prerequisite by the funder of the CHECC project. The current ESSL team is spread across many European countries including Germany, Austria, the Netherlands, Romania, and Croatia and often works remotely. The employee do their work through teleworking from Germany. In collaboration with the Institute of Meteorology of the Freie Universität Berlin, we offer a workplace at the Institute, which is the location of the other current ESSL CHECC researcher. It is expected that the new employee will coordinate with him and with other ESSL colleagues in weekly video meetings and will meet in person approximately every two to three months, in Berlin, Wiener Neustadt, or another agreed location. In case work in support of the ESSL Testbed is done, it is expected that the employee will take part in person in the Testbed in Wiener Neustadt for at least one week in June and/or July.

ESSL offers this position for a two-year period, limited by the duration of the funding for the CHECC project. Provided that subsequent funding is found, the employment may be continued beyond the two-year period, and could be made permanent. As a researcher at ESSL, you will be part of a small international team of ESSL which has become an important centre of competence in Europe with regard to severe convection. You will be able to contribute to the various other activities carried out and take part in ESSL courses taught by experts in the field.

We are looking for a person who has a Master or Ph.D. degree or equivalent in meteorology, physics, or a related discipline, who is enthusiastic about severe weather research. A well-organized, reliable, and communicative character is expected. For graduates of a Master’s degree, the work done for the CHECC project can be part of a Ph.D. degree (dr. rer. nat.) pursued at the Freie Universität Berlin or another university.

We require:

  • Good command of the English language in speaking and writing
  • An M.Sc. or Ph.D. degree in physics, meteorology, geophysics, mathematics or similar
  • An interest in (severe) convective storms
  • Experience with programming using languages such as Python, R, or similar

Beneficial, but not essential, are:

  • Having published in peer-reviewed literature
  • Having done prior research work related to atmospheric circulation patterns
  • Knowledge of the German language or willingness to learn German
  • Some knowledge of web-programming (HTML, PHP, JavaScript)
  • An interest in weather forecasting

The salary level is oriented at the German TvöD salary table, level E 13. In case the employee with carry out the research work (at 75%), an indicative net salary is around € 2000/month, depending on the applicable tax class according to German law and other factors.  In case the employee will also contribute to the Testbed and work full time (100%), an indicative net salary is € 2500/month.

With reference to ESSL’s diversity policy, we especially encourage women and minorities to apply. We are looking forward to receiving your application including a motivation letter and a curriculum vitae until February 28th 2021 by e-mail to Pieter Groenemeijer:

UPDATE – ESSL events in 2020 online

ESSL has decided to carry out all its events in 2020 online. We have collected experience with organizing such events and have received mostly positive feedback. That being said, we aim to organize event on site in Wiener Neustadt in 2021 as soon as the virus situation allows it. We are looking forward to welcoming participants personally to our expanded facilities.

Frequency rise of future European thunderstorm hazards

Researchers at the European Severe Storms Laboratory (ESSL), Munich Re, the Ludwig-Maximilians University Munich (LMU) and the German Aerospace Centre (DLR) could show that damaging convective weather events including lightning, hail and severe wind gusts are likely to become more common across Europe until the end of this century. An increase in convective instability as a result of rising humidity near the earth’s surface was identified as main reason for the increase in hazard frequency.

They applied a set of additive logistic regression models (AR-CHaMo) to an ensemble of 14 regional climate simulations to predict the frequency of severe thunderstorms and its associated hazards in Europe under projected anthropogenic climate conditions.

Simulated annual 6-hourly periods with (a), (b) and (c) hail ≥ 2cm (d), (e) and (f) wind (g), (h) and (i) with hail ≥ 5 cm. The first column (a, d and g) represent the historical period (1971-2000) while the second and third column show the percent change at the end of the century (2071-2100) for the (b, e and h) RCP4.5 and (c, f and i) RCP8.5 scenarios. Trends are called (very) robust where the change is larger than (twice) the initial standard deviation of the model ensemble. (Very) robust changes are indicated by (large) black dots in (b, c, e, f, h and i). Areas where models already diverge greatly for the historical period are displayed in gray in (a, d and g). From Rädler et al. (2019).

They projected a slight decrease in thunderstorm occurrence in southwestern and southeastern Europe, but an increase in the probability of severe weather. Large hail (≥ 2 cm) is projected to become 40%-80% more likely across central Europe in the RCP8.5 scenario by the end of the 21st century (Figure c ) while very large hail is projected to become more likely across most of Europe, with a doubling possible in parts of central and northeastern Europe (Figure i).  As a consequence of the rising hazard probabilities, risk models will need to be adapted and public warnings and precautionary measures should be issued as storms approach.

More information on this study can be found in this open access article: 
Anja T. Rädler, P.H. Groenemeijer, E. Faust, R. Sausen and T. Púčik, 2019: Frequency of severe thunderstorms across Europe expected to increase in the 21st century due to rising instability, npj Climate and Atmospheric Science, DOI:10.1038/s41612-019-0083-7

The severe convective weather season of 2018 has started

During recent days, pronounced severe convective storm activity has occurred across Europe, reports of which have been collected into the ESWD with help of ESSL’s partners. In total, we have received over 360 reports in the past 7 days. A majority of them were of large hail (184 reports), followed by severe wind gusts (79 reports) and heavy rainfall (66 reports). The first notable event was 29th April, where a tornadic supercell tracked more than 500 km from central France to Belgium. Wind damage caused by this supercell is still being investigated to confirm possible occurrence of several tornadoes along its path. On 1 May, a long-lived supercell over eastern Poland produced a hail swath 300 km long with hail up to 5 cm in diameter. And one day later, series of severe storms struck Croatia, Slovenia, Hungary and Austria. Hail up to 6 cm in diameter was observed over northeastern Slovenia, damaging houses and numerous flash floods were reported from Vienna, where storms persisted for several hours.