## 1 Introduction  
The south-central Andes is an area that is affected by hydrometeorological extreme events, e.g., [1; 2; 3; 4; 5; 6; 7]. The combination of topography and climate forms the most important driver for generating deep convective storms along the eastern central Andes, e.g., [8; 9; 10; 11]. Atmospheric water vapour content is a crucial variable triggering the convection and rainfall extremes in the south-central Andes [12]. Water vapour also plays an important role in controlling atmospheric stability as it is the primary variable leading to the formation of convective storm systems [13] by enhancing the convective available potential energy (CAPE) [14].  
However, direct and three-dimensional measurements of water vapour in the atmosphere are difficult and requires atmospheric sounding [15] or recent developments in radar processing, such as Global Navigation Satellite System (GNSS) methods, to monitor the atmospheric integrated water vapour (IWV) content [16; 17; 18]. GNSS-derived troposphere products calculated from the zenith total delay (ZTD) [19] are now used as reliable meteorological data in climate studies [20]. The advantage of GNSS-IWV measurements is their high spatial and temporal resolutions.  
Several previous research studies used GNSS atmospheric data to study extreme rainfall events [21; 22]. Some studies have shown and documented that the variations in the GNSS-IWV are temporally correlated with rainfall. These studies have shown an increase in the GNSS-IWV several hours before extreme rainfall, mostly followed by a decrease after the event [23; 24]. Furthermore, [PERSON] et al. [13] investigated the joint effect of GNSS-IWV and atmospheric pressure on extreme rainfall and they showed a high spatiotemporal correlation between the variations of GNSS-IWV and severe rainfall in eastern Spain. [PERSON] et al. [25] indicated that GNSS-IWV can show moisture variability in connection with severe storms in the Cuyo region in Mendoza in the south-central Andes. Thus, GNSS-IWV has been identified as a reliable parameter for detecting atmospheric convection and extreme rainfall.  
An additional parameter that triggers convection and rainfall extremes and describes the atmospheric stability is CAPE [26]. CAPE indicates the amount of energy available for convection [27]. [PERSON] et al. [28] defined CAPE as a proxy for extreme rainfall over the United States and Southern Canada. Furthermore, [PERSON] et al. [29] have shown a high contribution of CAPE to heavy rainfall during the monsoon season over the Indian region. A different study suggested that the spatial pattern of extreme-rainfall events can be described by a combination of the dew-point temperature and CAPE in the south-central Andes [4].  
These previous studies separately analysed the spatiotemporal distribution of extreme rainfall related to IWV and CAPE [25; 28], but they were not fully sufficient in explaining the joint contribution of both variables on extreme rainfall. Our study aims to identify the relationship between rainfall, GNSS-IWV, and CAPE and to analyse the effect of GNSS-IWV and CAPE in the presence of each other on extreme rainfall generation. We specifically focus on the south-central Andes where convection plays an important role in extreme rainfall generation.