A climatology of thunderstorms across Europe

A new study on the climatology of thunderstorms, “A climatology of thunderstorms across Europe from a synthesis of multiple data sources”, has been published in Journal of Climate. The study was led by Mateusz Taszarek from Adam Mickiewicz University in Poznań and co-authored by Tomáš Púčik and Pieter Groenemeijer from ESSL, among others.

Different datasets were used to investigate the climatology of (severe) thunderstorms across Europe, namely the ZEUS and EUCLID lightning detection networks, SYNOP observations, soundings, ESWD reports and the ERA-Interim data. Weaknesses and strengths of each of the datasets were discussed, as well as similarities and differences in the context of annual number of (severe) thunderstorms days and their annual cycles across various parts of Europe.

For example, the mean annual number of thunderstorm days based on lightning observations over Romania was lower compared to the ERA-Interim dataset, but higher over Hungary, southwestern Slovakia, the Czech Republic and southern Germany. Compared to SYNOP observations, lightning detection networks show higher number of thunderstorm days over most of Europe.

Mean annual number of thunderstorm days based on different datasets.
Figure © Copyright 2019 AMS.

While there were numerous differences between results obtained the individual datasets, the annual cycle was reproduced similarly by all of them. Datasets show that the thunderstorm season peak shifts from south to north from May to August over the continental parts of Europe and then shifts to the Mediterranean area in the autumn. Inland areas of Spain experience the peak in thunderstorm activity in May to June and the eastern coastal areas experience the peak in September to October.

Day of the year with peak thunderstorm activity.
Figure © Copyright 2019 AMS.

You can read more here:
Taszarek, M., J. Allen, T. Púčik, P. Groenemeijer, B. Czernecki, L. Kolendowicz, K. Lagouvardos, V. Kotroni, and W. Schulz, 2019: A Climatology of Thunderstorms across Europe from a Synthesis of Multiple Data Sources. J. Climate,32, 1813–1837, https://doi.org/10.1175/JCLI-D-18-0372.1.

ECSS Second Announcement

The Second Announcement and Call for Papers for the 10th European Conference on Severe Storms (ECSS2019) has been published.

Details on registration and abstract submission can be found on our ECSS webpage: http://ecss.eu

Please note the abstract submission deadline: 24 April 2019

Our local organizing partner IMGW and the European Severe Storms Laboratory are looking forward to Kraków! The ECSS is supported by MunichRe, EUMETSAT and the European Meteorological Society EMS.

Castle of Kraków (c) Alois M. Holzer

Lifetime Achievement Nikolai Dotzek Award 2018 for Bob Davies-Jones

The ESSL awarded Dr. Robert Davies-Jones with the Nikolai Dotzek Award for his lifetime achievement. Bob Davies-Jones is the first European to receive this prestigious award, to be presented at the upcoming ECSS in Kraków, Poland, where also the regular 2019 Nikolai Dotzek Award will be given.

Bob Davies-Jones is one of the founders of the modern theoretical description of supercell thunderstorms. Although he is perhaps best known for his contributions on supercell and tornado dynamics, he also has advanced the field of large-scale dynamics and made numerous contributions on basic fluid physics (often centered on one of the most important quantities to analyze tornadoes: vorticity).

Read more here (PDF)

Dr. Robert Davies-Jones at the ECSS 2013 in Helsinki
(c) Paul Markowski

Early season tornado outbreak over Turkey

While much of Europe remains under stable conditions, severe weather outbreak occurred over Antalya province, southern Turkey, between 24th and 26th January 2019. Outbreak included numerous instances of heavy rainfall resulting in flash floods, tornadoes, severe wind gusts and large hail (Fig. 1).

Fig. 1 Reports of severe weather between 24th and 26th January over Turkey based on ESWD.

On 24th January, three tornadoes affected the province, one of them rated F2, killing 1 and injuring 6 people. 2 F1 tornadoes occurred as well, injuring 1 person. Tornadoes inflicted considerable damage to homes, roofs and greenhouses.

On 25th January, flash flooding has killed 2 people in the same area.

On 26th January, a strong tornado, rated F2, struck Antalya airport, injuring 11 persons at the site. 8 passengers were injured on a transfer bus that was overturned and dragged by severe winds. 3 airport employees were injured in another shuttle. The event has gained significant attention on the social media as many videos and photographs were taken of the tornado. Tornadic storm would later produce additional F1 tornado and also instances of very large hail, damaging greenhouses.

This tornado outbreak is interesting from two aspects. The first is its occurrence in the middle of winter and out of the convective season throughout much of Europe. However, recent research on tornado climatology (Groenemeijer and Kuhne, 2014; Kahraman and Markowski, 2014) shows that January is actually the month with peak tornado activity over this part of Turkey (Fig. 2). A relatively warm sea with strong flow aloft combined to create marginal CAPE, low cloud bases and pronounced vertical wind shear in the lower troposphere (Fig. 3)

Fig. 2 Month with peak tornado activity over Europe from Groenemeijer and Kuhne (2014).

The second interesting aspect is that it shows the potentially high societal impact that tornadoes may inflict when striking vulnerable infrastructure, in this case an airport. Had the tornado been stronger and/or larger, the impact could have been much worse, with hundreds to thousands of people in danger. While tornadoes are considered rare in Europe, this is actually the second time in less than two years that a tornado got in close proximity of an airport, after the Vienna Schwechat airport incident on 10th July 2017. Tornadoes are in general an underestimated threat in Europe (Antonescu et al, 2017) and this recent case demonstrates a strong need to include tornadoes in national weather warning systems.

Fig. 3 Forecast of CAPE and bulk 0-3 km vertical wind shear for 26th January 2019, 06 UTC, based on 00 UTC run of ICON.

Spring seminars: early bird fees until 31 Dec

We would like to advertise the following seminars that can still be booked for reduced rates until the end of this month:

Our cornerstone seminar “Forecasting Severe Convection I” by Dr. Tomáš Púčik from 25 to 29 March 2019, which combines lectures with practical forecasting exercises. When this seminar was last held in October, it received a very high mean participant grade of 9.9 (on a scale from 0 to 10). Join and boost your ability in forecasting severe convection!

Our specialized seminar “Aviation Forecasting of Severe Convection” by Dr. Tomáš Púčik from 8 to 12 April 2019. In the past years a growing demand for this forecasting course tailored to aviation forecasters, evolved. At this moment, there are only 3 places left for this course. For autumn 2019 there is another such seminar planned.

Our high-level seminar “Dynamics and Prediction of Severe Convection” (Forecasting Severe Convection II) combines lectures from leading tornado and severe weather researcher Prof. Yvette Richardson from Penn State University in the USA, which practical forecasting exercises. This seminar is especially suited for advanced European forecasters, such as shift leaders, warning meteorologists, and to advanced students of meteorology and academic researchers with an interest in forecasting.

The full ESSL activities calendar for 2019 can be found here. 

Deadly flash floods in 2018

In our recent blog post about very large hail events of 2018, we mentioned that hail produces large damage. However, it is rarely deadly, in contrast to flash floods. Based on the data from  the European Severe Weather Database, by 12 December, flash floods have killed 152 people across Europe, parts of northern Africa and the Middle-East.

While most of the heavy rainfall events were reported in central Europe, the most deadly flash floods occurred in the Mediterranean area, including the 5 events with the highest number of fatalities, ranging from 12 to 21.

Heavy rain and deadly flash flood reports across Europe in 2018. 5 events with the highest number of fatalities are indicated.

Who was at most risk during the flash floods? Out of 35 events with more than 1 fatality we identified 16 that involved vehicles being swept away by the floods. Because not all reports include detailed description of the fatality circumstances, the ratio of events including fatalities in cars is likely even higher. The deadliest flash flood also involved a vehicle. In a tragic event on 25 October, a flash flood swept away a bus in Jordan, killing 21 persons onboard.

Besides vehicles, several events involved a group of hikers being swept away by flash floods in the narrow canyons. The first such event occurred in Israel, on 5 May and resulted in 10 fatalities. On  1 August, 5 hikers were killed on Corsica and 10 hikers drowned in the Pollino national park in Italy on 20 August.

This shows that data from the ESWD can be used not only to identify the areas with the highest severe weather incidence, but also to compare the impacts of severe weather phenomena or to find out which groups of people are at most risk in a given severe weather type.