Weather

Cyclogenesis and occlusion cloud bands are common meteorological phenomena which are tightly connected. While “cyclogenesis” is a process, describing the development of a low centre, which can last from few hours to several days, the occlusion cloud bands are the result of this cyclogenesis process. Occlusion cloud bands differ from cold and warm front bands because of their history as well as their physical status.
The two lectures start from the classical cyclogenesis (occlusion) processes which are related to the classical polar front theory and introduce then the conveyor belt view of these processes culminating in the warm and cold conveyor belt occlusion types.
The occlusion cloud band types are described and compared to cold and warm front types in their horizontal as well as vertical depiction.
Also special subtypes of occlusion processes like “instant occlusion” and "cold air development" are mentioned.

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Lecture slides

Fronts as described in the "Bergen school" by Vilhelm Bjerknes are early conceptual models. Parameters typical for the changing of air masses were named and used by forecasters to recognize transition zones (fronts) between air masses. For nearly a century the method from the Bergen school is applied in the majority of weather rooms all over the world. Satellite information expressed how right Bjerknes was in his CM thinking, but this information showed also that fronts can have a much more complicated structure and live cycle Bjerknes could imagine.
In the lecture we concentrate on warm- and cold fronts and show how we can analyze them with help of CM thinking.
It's not only fronts that forecasters should always keep an eye on, but also the frontal sub-structures like upper waves, front intensifications or newly developing systems. NWP models sometimes catch the situation, sometimes not. Especially for rapid or small scale developments, model performance may leave a lot of gaps in the processes.

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Lecture slides

Getting a good, actual weather picture within short time is essential for a forecaster who has to react quickly and adequately on weather changing's.

The huge amount of weather data which are available makes it almost impossible for a human being to handle. Thinking in conceptual models is the only way to deal with this problem

Within 20 years of the project fifty-three different conceptual models were described in a manual: Sat Manu. Also for the southern hemisphere, we have already fifteen CM's described.

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Lecture slides

Making reliable severe weather forecasts is always a great challenge. Communicating them towards the public and special end users is sometimes greater, even if the forecast is good. Tamás Alaga says that the Hungarian Meteorological Service (OMSZ) plans to develop and simplify its two-level warning system to make it more understandable. The problem is knowing when to stop with these simplifications. Tamás also explains how does the service handle probabilistic forecasts and delivering such forecasts to public and consumers.

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Summer thunderstorm Kiira left a significant trace in Finland in August of 2017. With big forest damages because of strong wind gusts, big number of interventions in southern Finland this case is suitable for analysis and through that presenting the Finnish severe weather follow-up product LUOVA. Kaisa Solin from Finnish Met Service explains LUOVA more in detail in the video.

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The presentation is delivered on the basis of the polar air outbreak in mid April 2017 that caused a late winter outbreak in the Alpine area in Austria. Because of that Austrian met service had to reactivate winter maintenance warnings. Thomas Turecek of Austrian Met Service (ZAMG) explains us how did they cope with this event and how are the warnings they issued connected with climatological thresholds for that specific area.

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ANYWHERE project is a H2020 funded project that aims to develop tools to support coordination of the emergency response operations to face challenge of the extreme weather and climate events. Tuomo Bergman from Finnish Met Service (FMI) tells us that the purpose is to build a pan-European multi-hazard platform for faster analysis and anticipation of the risk prior to event occurrence, improved coordination of the emergency actions and assist to raise the self-preparedness.

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Jyri starts his talk about what ISTIKE actually is and why was there a need for such collaboration between several rescue services in Finland. The main aim of the project is to provide a rescue center with a joint emergency center in eastern Finland. Jyri also describes what are the procedures when a certain severe weather event approaches and what are the preparedness levels of the rescue services. What is the role of other institutes?

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The Norwegian Met Service (MetNo) uses a wide variety of social media from Facebook and Youtube to Twitter and Instagram for delivering information to people around the country (and world). That way MetNo can post numerous short news, pictures and general weather information that people find appealing because of their shortness and informativity. On the other hand how are the extreme events reported through such services?

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Nuno Moreira from Portuguese Met Service (IPMA) is going to show us the current warning system used in Portugal. How are their decisions affected by the impacts that weather may have on wide variety of parameters that can then affect people? Social media are playing an important role in communicating weather information to people nowadays. How to, what and when to communicate certain warnings to people? Nuno will try to answer all of these questions from IPMA's point of view.

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A case study including three examples of tropical air advection into mid-latitudes is presented by Barbara Wrona from Polish Met Service (IMGW). These protrusions of warm and moist air caused convection and severe convection over a big part of the country. Barbara is going to analyze the latter one from the synoptic point of view and will tell us about the warnings that have to be issued in these cases.

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Severe weather warnings at MeteoSwiss started more than thirty years ago, firstly with warnings for heavy precipitation. After the storm 'Lothar' in 2001 warnings for wind, rain and snow have been introduced and then the system was updated in 2009 with new software, NinJo. After this short introduction, Daniel Murer from MeteoSwiss will present us a case that will illustrate the process of issuing warnings and decision making in the Swiss Met Service.

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