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.
10th edition of the ESSL Testbed is upon us and will be held in four weeks: 14–18 June, 21–25 June, 5–9 July and 12–16 July. The second and third weeks are for invited experts, or participants who have already been to the Testbed before or other courses. Like last year, the Testbed will be held online. 44 participants have registered, 12 people for the regular and 10 for the expert weeks.
Compared to 2020, there are a few new aspects. First, we have improved our WeatherData Displayer, which has a new, darker layout, and now allows a smoother switching between different regions. Moreover, a transparency option for data layers has been added. There is also more NWP data in the displayer compared to last year, including ensemble output from ICON-D2 (DWD) and C-LAEF (ZAMG). The third convection allowing model is Harmonie (KNMI). A large part of the data processing is now done in the European Weather Cloud, with thanks to ECMWF.
Besides daily forecasts of convective storms, we are going to evaluate new tools developed for forecasting and nowcasting of convective storms. This year we will concentrate on:
Extreme Forecast Index and Shift of Tails for CAPE and CAPE-shear from ECMWF
C-LAEF ensemble prediction system from ZAMG
ICON-D2 ensemble prediction system from DWD
Modified Lightning Potential Index from DWD
KONRAD3D cell-tracking nowcasting tool from DWD
STEPS-DWD radar nowcasting tool from DWD
NowcastSAT satellite nowcasting tool from DWD
We are looking forward to all the participants and interesting discussions on these new products and the hopefully interesting weather situations!
We welcome external persons to join the daily Testbed weather briefings from Tuesday through Friday during Testbed weeks starting at 11:00 CEST (0900 UTC) until approximately 12:30 CEST (1030 UTC). To join, visit this link: https://bluejeans.com/720241930
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.
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
We are looking for support of the project “Convective Hazard Evolution under Climate Change” (CHECC, see: https://www.essl.org/cms/checc/), part of the German research programme ClimXtreme (see: https://www.climxtreme.net/) 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:
the role of changes in synoptic scale weather patterns on severe thunderstorm
changes in the variability of weather conditions supportive of severe
on the research in peer-reviewed scientific journals
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.
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.
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
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.
command of the English language in speaking and writing
M.Sc. or Ph.D. degree in physics, meteorology, geophysics, mathematics or
interest in (severe) convective storms
with programming using languages such as Python, R, or similar
not essential, are:
published in peer-reviewed literature
done prior research work related to atmospheric circulation patterns
of the German language or willingness to learn German
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.
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: email@example.com.
A two-part study on the climatology of severe convective storms over Europe and the U.S. was recently published in the Journal of Climate. The study was led by Dr. Mateusz Taszarek of the National Severe Storms Laboratory (Norman, OK, USA) and Adam Mickiewicz University (Poznán, Poland) with contributions from ESSL among others. The study used lightning detection data, European Severe Weather Database reports, Storm Data reports and the ERA-5 reanalysis to answer the research questions.
Over the U.S., the fraction of lightning hours associated with severe weather reports is higher than over Europe with the exception of winter, when a seasonal maximum is observed over both areas. One can also clearly see stronger reporting inhomogeneity across European countries in contrast to the more homogeneous Storm Data that cover the U.S.. Compared to Europe, extreme events are considerably more frequent over the United States, with a maximum activity over the Great Plains. However, the threat over Europe should not be underestimated, as severe weather outbreaks with damaging winds, very large hail, and significant tornadoes occasionally occur over densely populated areas
While environments conducive to severe convection (characterized by the simultaneous occurrence of CAPE and shear) occur more frequently over the U.S., European severe storm environments more frequently result in storms. 30 – 40% of the thunderstorms over the midwest of the U.S. form in conditions conducive to severe weather, in contrast to 10 – 25% of thunderstorms over central and western Europe. Over Europe, the highest fraction of thunderstorms forming in severe environments is found over the Balearic Sea and the northern Adriatic Sea.
Additionally, an animation of the annual cycle of lightning activity, MLCAPE and 0-6 km vertical wind shear over both areas can be seen below. Over Europe, one can see a shift of thunderstorm activity from land to sea as the year progresses from spring and summer to autumn. In both areas, the seasonal increase in CAPE is accompanied by a decrease in shear and vice versa. The U.S. Midwest sees a pronounced combined occurrence of high CAPE and strong shear in the spring, while it occurs across western Mediterranean in autumn.
Taszarek, M., Allen, J. T., Groenemeijer, P., Edwards, R., Brooks, H. E., Chmielewski, V., & Enno, S. (2020). Severe Convective Storms across Europe and the United States. Part I: Climatology of Lightning, Large Hail, Severe Wind, and Tornadoes, Journal of Climate, 33(23), 10239-10261. Retrieved Dec 9, 2020, from https://journals.ametsoc.org/view/journals/clim/33/23/jcliD200345.xml
Taszarek, M., Allen, J. T., Púčik, T., Hoogewind, K. A., & Brooks, H. E. (2020). Severe Convective Storms across Europe and the United States. Part II: ERA5 Environments Associated with Lightning, Large Hail, Severe Wind, and Tornadoes, Journal of Climate, 33(23), 10263-10286. Retrieved Dec 9, 2020, from https://journals.ametsoc.org/view/journals/clim/33/23/jcliD200346.xml
Severe weather outbreaks in autumn are quite typical over the Mediterranean but rarer over continental parts of Europe. On 4 and 5 October, an unusual synoptic-scale situation led to an outbreak of severe thunderstorms over eastern Slovakia and Poland.
During these two days, a total of 36 large hail reports (with 5 reports of hail exceeding 5 cm in diameter), 71 reports of severe wind gusts (with several instances of F1 damage), 4 reports of damaging lightning and an F1 tornado report were entered into the European Severe Weather Database (eswd.eu). The map below gives an overview of the impacts. While severe convective wind gusts are not uncommon with deep low pressure systems over this part of Europe, hail reaching 7 cm or more in diameter is exceptional for this time of year.
The outbreak was caused by severe thunderstorms developing in a very warm and moist airmass that had been advected northward from the southern Mediterranean Sea (Fig 2). Mixing ratios of 10 – 12 g/kg allowed 500 – 1500 J/kg of MLCAPE to build over the area. Combined with strong vertical wind shear (exceeding 20 m/s in the 0-3 km layer), thunderstorms quickly turned severe as they organized into supercells and bow-echoes.
More information concerning the F1 tornado over southern Slovakia can be found here. ESSL would like to thank Skywarn Polska and the Slovak Hydro-Meteorological Institute for providing severe weather reports!
In November, ESSL and EUMETSAT are introducing a new course called “Optimal use of satellite data in forecasting severe convection“. The course will concentrate on how to effectively use satellite data in nowcasting severe convection and will provide both the theoretical background on the basic dynamics of severe convective storms, as well as a satellite perspective on each discussed topic. In the afternoon, we will apply the gained knowledge in a forecasting / nowcasting exercise using the selected case studies. Click on the link above to find out more.
The course will last 4 days between 16 and 19 November and will be held online, so there is no need to travel anywhere. The early fee period has been extended till 30 September. So, if you are interested, please do not wait too long with registering here.
Tornado forecasting can be very challenging, especially in low CAPE – high shear environments and when lower tropospheric shear is only locally enhanced. Such was the case of an F1 tornado that hit the village of Lekárovce in eastern Slovakia on 3 October 2018. This tornado is the main subject of a paper “A Challenging Tornado Forecast in Slovakia” that has been recently published in the journal Atmosphere. The study was led by Miroslav Šinger from Comenius University and Slovak Hydrometeorological Institute in Bratislava and co-authored by Tomáš Púčik from ESSL.
Authors of the study attempted to reconstruct the
environment leading up to the tornado based on the observational datasets and
compared it with the model data that was available to forecasters in the
morning hours before the tornado. One of the main aims of the paper was to show
whether observational data or the higher resolution run of the local model
would improve the ability to identify conditions favourable for tornadogenesis.
Tornado occurred in the early afternoon hours underneath strong west-northwesterly mid to upper tropospheric flow at the flank of a deep low-pressure system. Enhanced lower tropospheric moisture combined with mid-tropospheric lapse rates of 6.5 K/km allowed for a build-up of marginal CAPE reaching 200 – 300 J/kg.
But while the deep-layer shear was very strong, models predicted a decrease in 0-1 km shear between morning and early afternoon hours with surface wind veering from East to West. However, easterly wind direction persisted over eastern Slovakia for much longer, yielding strong lower-tropospheric shear as the storms developed in the afternoon. Study shows that using both observational datasets and the higher resolution version of the local area model would alert the forecaster to the presence of strong lower tropospheric shear over the area of interest.
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.
The tornado outbreak of 24–25 June 1967 remains the second deadliest tornado outbreak over Europe since 1950 after the tornado outbreak of 9 June 1984 over Russia. Over the course of two days, one F2 tornado, four F3 tornadoes, one F4 tornado, and one F5 tornado struck France, Belgium and Holland (Fig. 1), resulting in 15 fatalities and 234 injuries.
In a study from 2018, a team led by Bogdan Antonescu looked at the details of the outbreak and at what would be the consequences if a similar tornado outbreak will occur 50 years later (i.e., 2017). This was done by transposing the seven tornado tracks from the June 1967 outbreak over the modern landscape. Due to urban growth, it is possible that tornadoes could cause even more impact than in 1967. Based on the statistics of fatality and injury rates associated with European extracted from the European Severe Weather Database, a similar tornado outbreak with the one that occurred in 1967, would result in 55–2580 injuries, and 17–172 fatalities. In the worst-case scenario, with tornado tracks moving over highly populated areas over the region, up to 146 222 buildings could be impacted with 2550–25 440 injuries and 170–1696 fatalities. This study clearly shows how impactful such a tornado outbreak could be to society.
A follow-up study that has just been published in Weather and Forecasting (link) hindcasts the tornado outbreak using an WRF-ARW simulation, with initial and boundary conditions provided by ERA-40 reanalysis and the highest-resolution domain with 800-m grid spacing. The model simulated an environment conducive for tornadic supercells with CAPE exceeding 2000 J/kg, 0–6 km bulk shear between 20–25 m/s and Storm Relative Helicity reaching 300 m²/s² in the 0–3-km layer. The model was also able to explicitly simulate a number of supercells over the region of interest (Fig. 2).
One of the questions posed by the article is how would a forecast of such an event look like today? To do this, an ESTOFEX forecaster was presented with a set of forecast maps for both days (without knowing the dates) and asked to provide Day-1 outlooks. The forecaster issued Level 3 (the highest risk of severe weather) for both days, on (Fig. 3). This paper demonstrates that, with our understanding of severe convective storms and state-of-the-art numerical modelling, a forecast of a tornado outbreak over Europe is possible. Given how much societal impact significant tornadoes can cause, addressing their threat should be part of any convective storm forecast.
Full versions of both studies can be freely accessed here:
In the beginning of January, we published a series of posts on social media about severe weather in 2019. This blog puts together this information and graphics, and provides an overview of the most prominent severe weather events of the year.
2019 was a comparatively active severe weather year. ESSL received 3275 reports of large hail as well as 12 027 severe wind gust reports, 792 reports of tornadoes and 3924 of heavy rain. This year has the highest number of large hail and heavy rain reports since the ESWD was established in 2006, and it was exceptional especially regarding the large hail. For example, more than 96 hail-related injuries were reported with 15 hail events, while hail injuries were reported only 96 times in the whole history of the database. In addition, 14 events included giant hail, reaching or exceeding the size of 10 cm. Further fatalities and injuries were reported with severe wind gusts: 66 and 414, respectively.
Tornadoes caused 3 fatalities and 97 injuries and were reported mostly near the coasts of the Mediterranean Sea. 531 out of 792 tornadoes occurred exclusively over water, and can thus be called waterspouts. There were 28 strong tornadoes during the year, of which 27 were rated F2 and 1 F3. Heavy rain caused 145 fatalities and 77 injuries. Most of the reports came from Central Europe and from Italy.
In total, severe weather killed 394 people and 1112 people were injured during 2019. Most of the fatalities were attributable to heavy rainfall, followed by avalanches and lightning. Most of the injuries were caused by severe wind gusts, followed by lightning and hail. While heavy rain comprised 37% of all fatalities, it contributed to only 7% of injuries. Tornadoes caused about 1% of fatalities and 8% of injuries. This shows how differently the impact of severe weather phenomena can be.
Below, you can find a list of 10 major severe convective storm events across Europe in 2019. Please note that this overview was selected subjectively by the ESSL staff and is not an exhaustive list of all major severe weather events that occurred in Europe in 2019.
26 January: Tornado outbreak over Turkey
The year started with an active severe weather period over the southeastern Mediterranean. On 26 January 2019, a local outbreak of tornadoes occurred over southern Turkey. 15 tornadoes were reported in total, two of which were rated F2. One of the strong tornadoes struck Antalya airport around 8 UTC, overturning a bus with passengers that resulted in 11 injuries. Numerous videos of this event appeared online. Besides tornadoes, storms also produced hail up to 4 cm in diameter over the land, damaging crops and cars.
4 June: Convective windstorm and tornadoes over western Germany and the Benelux
On 4 June, first thunderstorms formed over northern France in the late afternoon and quickly moved northwest, forming a large convective system. A swath of severe wind gusts was reported over Benelux with the highest measured gust of 30 m/s. In addition, several tornadoes occurred including two strong, F2 tornadoes: one in the Netherlands and one in western Germany.
10 to 11 June: Damaging hailstorms
10 June marked the beginning of an active period of severe weather over many parts of Europe. The most notable event on 10 June was a hailstorm that struck parts of Munich in the afternoon hours. Wind-driven of hail up to 6 cm in diameter, caused extensive damage to hundreds of cars and roofs. This event is set to be the most costly thunderstorm-related loss in 2019, with estimated losses of $ 800 million.
One day later, severe weather activity continued, and while no major economic losses were reported like the day before, the storms produced even bigger hail. Giant hail was reported from two locations: From the border of Slovenia and Croatia (up to 11 cm in diameter) and across western Poland (up to 12 cm in diameter). For Poland, this marked the largest documented hailstone.
1 July: Widespread severe weather over Europe
372 severe weather reports were collected in a belt from eastern France through Switzerland, northern Italy, southern Germany, the Czech Republic and Poland into Ukraine, making this day perhaps the most widespread severe weather outbreak of 2019 over Europe. Severe storms produced numerous reports of large hail, up to 7 cm in diameter and severe wind gusts. Such large hail was reported both in France and the Czech Republic. The strongest wind gust speed was measured to be 35 m/s in eastern France. Five people were injured by gusts in France and six in Italy, where the severe wind also caused one fatality.
10 July: Damaging wind gusts and giant hail over Italy and Greece
This was the last of a multi-day outbreak of severe storms over Italy and parts of the Balkans (more information on the whole outbreak can be found in a previously published blog post). On this day, severe thunderstorms had already formed over Italy during the morning with two tornado and several severe wind gusts reports. Shortly after 10 UTC, giant hail, up to 14 cm in diameter, was observed over the town of Pescara in the region Abruzzo, Italy. The hail that was combined with severe wind gusts injured 20 people. Further hail and severe wind gusts were reported across Italy later in the day.
Injuries were reported also with storms that impacted Greece during the afternoon. However, the most severe event unfolded in the evening around 19 UTC, when a storm system that had travelled hundreds of kilometres from Italy, rapidly strengthened as it crossed the Aegean Sea and hit the Halkidiki peninsula. There, 6 people died and more than 120 were injured due to the severe wind gusts. Many of the injuries resulted from loose outdoor furniture being flung into groups of tourists seeking shelter.
9 August: Severe wind gusts and tornadoes over western Europe
Severe storms occurred in a belt from southern France to the northern Netherlands. Severe weather began in the afternoon after 14:00 UTC with severe wind gusts and large hail over northern France. The most severe period occurred between 15 and 16:30 UTC with isolated supercells producing swaths of wind damage, including an F2 tornado that crossed from France into Luxembourg and caused 19 injuries in the town of Pétange, Luxembourg. Over eastern France, two weather stations clocked the wind gust measurements of 35.8 and 42.7 m/s. Later on, two F1 tornadoes were reported from the Netherlands between 19 and 20 UTC. One of them occurred directly in the centre of Amsterdam.
22 August 2019: Deadly lightning strikes in Poland and Slovakia
Weak thunderstorms formed over central Slovakia during the morning hours and moved towards the High Tatras mountains on the border between Slovakia and Poland. Hundreds of hikers were caught unprepared by the storm, resulting in a total of 5 fatalities and 159 injuries. The worst lightning strike was reported from Mt. Giewont in southern Poland with 4 fatalities and 156 injuries. People were knocked down from the mountain or received burns as they held on the steel cable supporting them on the steep ascent to the mountain. Rescue efforts continued till the late night. 1 person died and 3 were injured on the Slovakian side of the Tatras. The Mt. Giewont lightning strike set the record for the highest number of directly-caused lightning injuries in the ESWD.
11 – 12 September 2019: Flash floods over Spain
Within an easterly onshore flow bringing moisture rapidly inland, a quasi-stationary convective line formed over València in the late-night hours of 11 September 2019. After hours of extremely heavy rainfall, flash flooding followed in the morning of 12 September. By 03 UTC on 12 September, 359 mm of rain fell at the Benniarés station with a maximum 6 hourly sum of 191 mm. Station Ontinyent reported 296 mm of rain by 05 UTC, with 242 mm falling since midnight. 5 people perished during the flash floods, which brought widespread disruption to the region and left several settlements completely flooded. Besides heavy rain, an F1 tornado was reported shortly after midnight on 12 September.
4 October 2019: Giant hail over Greece
While large hail is not unheard of during the autumn over the Mediterranean, flash floods are usually the dominating risk of severe storms during that time of the year. However, on 4 October, a supercell that tracked over the Attica region, Greece, produced an impressive swath of large hail. Giant hail up to 11 cm in diameter was reported from 3 different villages. Of course, cars, roofs and windows were badly damaged by this storm.
1 December 2019: Flash floods over southern France
December did not start well for some in southern France. After high amounts of rainfall in the past period, another round of heavy rainfall led to flash floods that severely impacted the Provence region. Weather stations reported 130 – 150 mm of rainfall falling during the day. While such amounts are not too high for the given region, previous rainfall exacerbated the situation. The flash flooding resulted in 5 fatalities and many people had to be evacuated from their homes.