## 2 Materials and Methods
### Synoptic Description of the Two Case Studies  
The two case studies observed over France in 2022 present different precipitation features. The April case (22-25 April 2022) which lasted 72 h produced precipitation over a large part of the south of France, whereas the June case (24-28 June 2022) lasted 96 h over the centre of France (Figure 2).  
Figure 2a shows that the precipitations of the April case were mainly important over the mountainous areas, such as over the west of the Massif Central (WMC), South Alps (SAL), Durance valley (DUR), Cevennes (CEV), and Jura (JUR) (see Figure 2c for localisation) where the highest accumulations, respectively, observed were 75.9 mm at Montredon-Labessonnie (43.72\({}^{\circ}\) N, 2.33\({}^{\circ}\) E), 59.5 mm at Comps-sur-Artuby (43.66\({}^{\circ}\) N, 6.47\({}^{\circ}\) E), 62.4 mm at Apt (43.88\({}^{\circ}\) N, 5.40\({}^{\circ}\) E), 85.1 mm at Barnas (44.67\({}^{\circ}\) N, 4.17\({}^{\circ}\) E), and 31.8 mm at Ballon de Servance (47.83\({}^{\circ}\) N, 6.79\({}^{\circ}\) E). The median accumulated precipitations recorded over the mentioned regions were 26.6 mm, 31.4 mm, 23.5 mm, 22.3 mm, and 25.4 mm over WMC, SAL, DUR, CEV, and JUR, respectively.  
For the June case, the precipitation amounts reached higher values around the northern Massif Central (NMC), such as at Chastreix (45.51\({}^{\circ}\) N, 2.74\({}^{\circ}\) E) and Clermont-Ferrand (45.79\({}^{\circ}\) N, 3.15\({}^{\circ}\) E) stations where 136.7 mm and 106.7 mm of rain were observed, respectively (Figure 2b). Nevertheless, the median accumulated precipitation recorded over this area was 35.7 mm.  
Figure 2: Rain accumulation measured by the RADOME rain-gauge network at the end of the April (**a**) and June cases (**b**). Panel (**c**) indicates localisations of the several areas of interest mentioned in the text. The red areas correspond to the April event, the blue areas correspond to the June event, and black markers are the localization of the radars mentioned in this study.  
The contrasted precipitation distributions observed for these two cases present different synoptic conditions displayed by the ECMWF ERA5 meteorological fields (Figure 3, [63]).  
For the April case, a marked depression located over northwestern Spain on 22 April slowly moved northeesterly with decreasing intensity. On 23 April 12:00 UTC, this depression was centred over southwestern of France (Figure 3a). Then, it disappeared, inducing a weak west-east stationary front in the middle of France.  
For the June case, the temperature over France was warmer than for the April case. An intense depression was present over the British Isles and a weak anticyclone was over Italy (Figure 3b). These pressure systems were, respectively, associated with cold and warm temperatures inducing the formation of an intense cold front through France (Figure 3b). During the June case, the depression movedoutheasterly, brought colder and more humid air mass over France. Thus, the more marked depression encountered during the June case brought intense precipitation along the cold front, whereas the less marked situation observed during the April case brought less-intense precipitation over a larger area (Figure 2).