## 1 Introduction
Changes in frequency and intensity of extreme weather events (e.g., storms),precipitation, heavy rainfall, and flooding are the potential impacts of an intensified water cycle. However, the potential future alterations in the earth's climate and weather conditions in response to the human-induced planet's warming will not be geographically homogeneous [1]. Some parts of the world will experience more pronounced changes, but some regions will experience less noticeable changes. In particular, main characteristics of rainfall and other forms of precipitation (their amount, intensity and frequency) will experience strong spatial variations [14]. Greater volume of precipitation is expected in high latitude regions and in the tropics, while in subtropical arid and semi-arid regions and many mid-latitude regions rainfall amounts will decrease [1; 15; 16; 17; 18]. Consequently, geographical areas with increased amount, intensity and frequency of precipitation and, moreover, areas that will also be seriously affected by sea level rise (coastal areas), will likely to experience increased risk of hazardous hydrological events, such as flooding. The spatial and temporal heterogeneity of climate change (variations in the trend (cooling or warming) and magnitude of climate change over space) is determined not only by the geographic location of the region in question, but also by the general circulation of the atmosphere (GCA) which involves a wealth of air motions with scales on the order of thousands of kilometers such as the westerly mean flow in the mid-latitudes in both the northern and southern hemispheres, planetary waves, large-scale extratropical transient eddies (cyclones and anticyclones), monsoons, and trade winds [19; 20; 21; 22; 23; 24]. One of the main dynamical mechanisms leading to the meridional transport of heat, moisture, and momentum from the tropical to polar latitudes and, thereby to the global redistribution of atmospheric moisture, are the large-scale extratropical eddies (cyclones) [19; 20; 21; 22]. The so-called \"atmospheric rivers\" that transport water vapor outside of the tropics through the extratropics (middle latitudes) are associated with mid-latitude cyclonic eddies and their frontal zones [25; 26]. Recent studies have indicated an increase in intensity of extratropical cyclones and a decrease in their frequency [27; 28; 29; 30; 31; 32; 33; 34]. Baroclinic instability, a specific type of dynamical instability of the zonal atmospheric flow with the equator-to-pole (meridional) temperature contrast (gradient) and, therefore, with a vertical wind shear (thermal wind), in the field of Coriolis force, is the principal mechanism by which extratropical cyclones form and evolve [35; 36; 37; 38]. The infinitesimal perturbations growing in such a flow derive their energy from the transformation of mean available potential energy (MAPE) which, in turn, depends on the tropospheric meridional temperature gradient (MTG); the larger the temperature differences between the equator and the pole, the greater the MAPE [39; 40; 41]. However, MTG is not the only fundamental parameter that determines the development of baroclinic instability in the atmosphere and, therefore, the formation of extratropical large-scale cyclonic eddies. The effective static stability of the atmosphere plays an equally important role in the generation of cyclones (e.g., [42; 43; 44; 45]). Unlike the so-called \"dry static stability\" of the atmosphere [21], the effective static stability takes into consideration not only the vertical thermal stratification of the air (temperature lapse rate \(\Gamma=-\partial T/\partial z\), where \(T\) is an air temperature, and \(z\) is a vertical coordinate), but also the effects of water vapor condensation, namely latent heat released into the atmosphere when the water vapor changes its state to a liquid. In consequence of latent heating, the effective stability of the moist atmosphere in mid-latitudes is less than the static stability of the dry atmosphere by about 40% [45].