Participants and ESSL Team during 2nd week of the ESSL Testbed2015.

Currently we are having a break from our Testbed activities, 3rd Testbed week starts on 15th June. However, it is worth to make a short summary of the previous week and participant’s forecasts. Total of 6 participants from 6 different countries took part in 5 expert lectures and within the support of the 3 ESTOFEX forecasters prepared 8 day1 and day2 forecasts, 12 nowcasts and  6 day3-5 forecasts. The most important days in the context of severe weather were Thursday, Saturday and especially Friday. Below we present the most interesting forecasts where participants managed to predict severe weather quite well! It is also worth to highlight Day4 and Day5 forecasts that relatively well pointed out areas where severe weather was likely. We start with the longest lead time forecasts:

Few of the nowcasts that were issued by our participants were very distinctive in distinguishing areas where severe weather was likely, below we present 2 best nowcasts, the second one with large hail nowcast is very impressive (6 reports)! Well done!

… and some pictures of the participants and ESSL Team during their work on Friday! 😉

Pieter working very hard on programming the ESSL Testbed nowcast display and sounding data.

Alois and Christoph working with participants on the Day3-5 forecasts.

Nowcasting activities!

Catrina, Maria and Jan working on the forecast.

Lars Tijssen and Thomas Schreiner during their ESSL work.

… and the other side of the table, Tomas Pucik and Mateusz Taszarek accompanied by Thomas 😉

Catrina presenting the Day1 forecast.

Christoph Gatzen and Tomas Pucik during the weather briefings.

Helve presenting the Day2 forecast.

Fully focused participants 😉

This day passed under very interesting discussions about weather setup that is currently going on in western Europe and expert lecture presentation given by Christoph Gatzen. In the morning Pieter Gronemeijer discussed the basis related to updraft speeds in convective cells and influance of mesocyclone on the increase in updraft stength. Then, our participants prepared convective outlooks for this day and tomorrow. Weather briefings were presented by today’s group leaders: Maria Frada and Miroslav Singer. Few pictures from this day tomorrow:

Pieter Groenemeijer discussing the importance of rotation in convective cells on the strength of the updraft.

Early morning opening session.

Day 2 forecast presented by Miroslav Singer

Day 1 forecast presented by Maria Frada

Christoph Gatzen (ESTOFEX) giving lecture on convective windstorms in Europe.

And the Day1 and Day 2forecasts:

Stay tuned! Tomorrow our participants will update forecasts for Friday and Saturday.

Nowadays we do not have good synoptic patterns that would favor occurrence of severe weather over Europe. However, our predictions expect that good overlap of instability and shear may occur in western Europe on Friday and Saturday. These forecasts are quite distant, but general setup is likely to appear. Below, some pictures from Testbed activities:

Tomas working with a participants in a “Day1 group”.

Mateusz working with a participants on a Day 3, 4, 5 forecasts.

This week Christoph Gatzen from ESTOFEX joined us as well.

And here are the forecasts for Wednesday, Thursday, Friday and Saturday:

Today we expect new participants of the second week of ESSL Testbed2015 from Austria, Romania, Germany, Portugal, Slovakia, Netherlands and Czech Republic. We start our introductory session at 12 UTC. In this week participants will also work in two groups with Tomas Pucik and Mateusz Taszarek. In addition, also Christoph Gatzen from ESTOFEX will support forecasting. Before we began new week, let’s take a look at the forecasts verification from the last days of the 1st week.

On friday, one of the group managed to predict tornado that occurred in Bavaria. They included quite detailed forecast description:

“A level 1 was issued for S Germany, W Czech Republic and parts of Poland mainly for large hail, severe wind gusts and in lesser extent for tornado (especially in E Bavaria and W parts of Czech Republic).

(…) Because LLS will locally exceed 10 m/s it cannot be ruled out that some isolated tornado event is possible. We pedict that convective cells will remain isolated, which somehow increases probability for tornado.(…)”

Tornado occurred near Freystadt around 16 UTC.

Thunderstorms in Europe during the 1st ESSLTestbed week were not very active in producing severe weather phenomena. However, we were able to predict  few waterspout, large hail and heavy rain cases, mainly in the SE and E Europe. In the last day our participants focused on evaluating nowcasting and NWP products tested in the testbed. In the morning hours we also divided them into two groups to prepare forecast for this day in the Central European domain. One group was supported by Tomas Pucik while the other by Mateusz Taszarek. Here are these two forecasts:

Our forecasts were consistent in expecting supercell thunderstorms over S Germany and W Czech Republic. We also predict organized line of storms (along the cold front) approaching Benelux and NW Germany in the evening hours. Participants were also very active in preparing and analyzing recent surface observational data. Forecasts were presented on the teleconferencing session by Susanne Theis (DWD) and Anna Wozniak (IMGW).

Team A working on the forecast

Team B working on the forecast

Anna Wozniak

Susanne Theis

Very interesting lecture of the day was given by Tomas Pucik, who presented his current research on sounding-derived parameters and their use in forecasting particular severe weather phenomena (tornado, large hail, severe wind gusts, heavy precipitation) associated with thunderstorms.

Tomas Pucik

Looking forward for the severe weather during the next week!

This day was opened by Mateusz Taszarek who started with the forecast verification. The main area of interest was SE Europe with the level 1 threat for E Greece, Aegean Sea , part of Turkey and Bulgaria, and level 2 for SW Turkey. As it turned out we successfully predicted thunderstorms producing large amounts of small hail in Greece and tornado over N Aegean Sea.

Mateusz Taszarek

Tornado in the N parts of Aegean Sea, 27th May (source: ESWD)

However, there were no thunderstorms over W and SW part of Turkey. This was a little suprise for us, because almost all models were consistent with producing convective initiation over this region. Also advection of potential vorticity, orographic lift, low-level convergence and good boundary layer moisture suggested good conditions for thunderstorm developement.

Even sounding from Izmir for 12UTC indicated nice CAPE and lack of convective inhibition:

… but in reality nothing happened there, and we could not find the reason why. Sometimes no matter how you try, the Mother Nature keeps her secrets to herself!

15 UTC 27 May, Sandwich product.

After the verification, our participants began to start with Day1 and Day2 forecasts. Afterwards, weather briefiengs on the teleconferencing session were presented by Maria Orawczak and Bernd Zeuschner.

Maria

Bernd

And this is a forecast for tomorrow. We expect some supercells over German – Czech Republic border and the line of storms passing eastwardly through N Germany in the late evening hours. Tomorrow in the evening we will see what happened.

The lecture of the day on the mesocyclone detection and radar products was given remotely by Thomas Hengstebeck (DWD). Our day ended with the testing radar products from DWD and testing the performance of COSMO-DE and COSMO Ensamble numerical models on the example of tornadoes in Germany on 5th and 13th May.

Today our day started with the verification of yesterday’s forecast that was conducted by Tomas Pucik. As it turned out, the forecast was quite good, however no severe weather reports were available in the level 2 area.

Tomas Pucik

Then, participants started to prepare their Day1 and Day2 forecasts with the support of Mateusz Taszarek and Tomas Pucik. Finally, these were presented by Stavros Dafis and Robert Herrmann.

And here are the forecasts:

Forecast for 27 May

Forecast for 28 May

Today participants started to work very hard on their nowcasting and forecasting workshops. At the beginning of the day we divided into two teams, the one was working with Tomas Pucik on today’s forecast while the second one together with the support of Mateusz Taszarek created forecast for tomorrow (27th of May) for SE EU domain:

After the forecasts have been made, they were presented on the Saba teleconferencing session by Helge Tuschy and Tanja Renko:

Finally, just before the lunch break Susanne Theis (DWD) gave the lecture on COSMO-DE-EPS and ICON-EU numerical weather prediction models.

Susanne Theis (DWD)

Participants during the lecture

After the lunch break participants got back to their duties. First team started to work on the day 3-5 convective outlook while the second one faced the difficulty of nowcasting severe thunderstorms in the Ukraine, Belarus and Poland.

Forecast for 28th May

Forecast for 29th May

Forecast for 30th May

Tomas Pucik having a discussion with Helge Tuschy on nowcasting

In the end of the shift, thunderstorms over Poland and Ukraine evolved into nice MCS!

Sandwich satellite image + CAPE +6h GFS forecast + roaming sounding tool + surface observations at 1700 UTC. Please note the overshooting tops on the Ukraine-Poland border

Tomorrow we start our session at 0700 UTC with the verification of our nowcasts and forecasts.

ESSL Testbed 2015 just started!

International team consisting of Alois Holzer, Tomas Pucik, Lars Tijssen, Mateusz Taszarek, Helge Tuschy and Magdalena Pichler opened the first week of the Testbed. The only one person who was missing was Pieter Groenemeijer, the director of the ESSL. He will join us on Wednesday.

ESSL Testbed 2015 team. From the left: Mateusz Taszarek, Helge Tuschy, Tomas Pucik, Magdalena Pichler, Lars Tijssen and Alois Holzer.

At the 1st week we have participants from Greece, Germany, Croatia and Poland.

The opening session was conducted by Alois Holzer who introduced participants to the concept of the Testbed. Then the basis of scientific forecasting was given by Tomas Pucik. Finally, the Testbed nowcasting display was discussed by Mateusz Taszarek

Alois Holzer and introduction of the Testbed concept.

Participants during Alois’s presentation.

In the end, participants within the use of DWD nowcasting experimental products were studying the severe weather outbreak from 13th May in south-western Germany. The analysis yielded that low and mid level rotation tracks were good in identifying tornado threat while the vertically integrated ice was good in estimating the potential of the supercell to produce a large hail. .