## 2 Weather Nowcasting  
The World Meteorological Organization (WMO) [4] mentions that \"nowcasting plays an increasing role in crisis management and risk prevention, but its realization is a highly complex task\", the highest difficulties being related to the small-scale nature of convective weather phenomena. This implies that the Numerical Weather Prediction approach is not feasible and that the forecast has to rely mainly on the extrapolation of known weather parameters. In this context, there is a high need for automated tools and systems supporting the nowcasting meteorologist, so significant research and development have been carried out on the topic of nowcasting. In spite of those efforts, both the operative personnel in nowcasting and the beneficiaries (population, relevant public institutions) are in demand of even more efficient products and services concerning the weather forecast itself and the alerting system. Most of the currently existing operational and semi-operational methods for nowcasting are using the extrapolation of radar data and algorithms mainly based on cell tracking. [PERSON] and [PERSON] developed a real-time cell tracker named TITAN [10] which is useful for single cells. A centroid method is used in Reference [10] to identify storm entities in consecutive radar scans and estimate future movement of the storm centroid by minimizing a cost function. SCIT was proposed by [PERSON] et al. [11] as a cell-tracking algorithm with a more more complex cell detection method. SCIT used reflectivity thresholds and a distance function between cells for tracking and estimating future positions. An operational nowcasting tool called TRT was developed by [PERSON] et al. [7] and used by Meteo Swiss. TRT is a centroid cell-tracking method using radar data and, in addition to previously mentioned methods, a multiple sensor system. [PERSON] and [PERSON] [12] introduced a cell-tracking algorithm using fuzzy logic based on a large set of historic radar data, with the goal of minimizing errors induced by single features. Germany's National Meteorological Service DWD uses a nowcasting system called NowCastMIX developed by [PERSON] et al. [8]. NowCastMIX employes remote and ground observations analyzed using fuzzy logic rules. AROME [13] is a small scale numerical prediction model, which is used by Meteo-France since 2008. Measurements used by AROME include measurements of the precipitation systems, of low level humidity, low-level wind, upper level wind and temperature and it provides a forecast for up to 30 h. AROME-NWC [9] was developed in 2015 on top of AROME, for nowcasting in the range of 0-6 h. The INCA system [14] was developed specifically for mountainous regions with the goal of forecasting for precipitation amounts, temperature, wind and convective parameters. An important limitation of existing centroid cell-tracking algorithms lies in the detection of storms segments having irregular shapes or with variable wind speeds, resulting in identification and tracking errors. Errors also occur when storm cells are clustered together and the algorithm detects them as a single larger cell. In other cases, a single storm cell is detected as two or more cells at the same horizontal location but on different altitude levels. Given the high spatial and temporal resolution, NowCastMIX [8] estimates of severe storms change quickly with the assimilation of new observations, leading to difficulties in reasoning for meteorologists. It is also prone to an overestimation of the likelihood of severe convection. According to Reference [14], the INCA system provides high accuracy for temperature but comparatively low for wind and precipitation given the relatively low distribution of relevant stations in mountainous regions. The systems described in References [8; 9; 14], which are considered to be some of the most performant automated nowcasting systems at the present time are highly customized for their respective location and infrastructure, thus their performance and adaptability to other contexts is unclear.