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On the basis of 180 storms which took place between 2004 and 2011 over the province ofMendoza (Argentina) near to the Andes Range at southern mid-latitudes, we consider thoseregistered in the northern and central crop areas (oases). The regions affected by these storms arecurrently protected by an operational hail mitigation project. Differences with previously reportedstorms detected in the southern oasis are highlighted. Mendoza is a semiarid region situatedroughly between 32S and 37S at the east of the highest Andes top. It forms a natural laboratorywhere different sources of gravitywaves, mainly mountain waves, occur. In this work,we analyzethe effects of flow over topography generating mountain waves and favoring deep convection.The joint occurrence of storms with hail production and mountain waves is determined frommesoscale numerical simulations, radar and radiosounding data. In particular, two case studiesthat properly represent diverse structures observed in the region are considered in detail. Acontinuouswavelet transform is applied to each variable and profile to detect the main oscillationmodes present. Simulated temperature profiles are validated and compared with radiosoundingdata. Each first radar echo, time and location are determined. The necessary energy to lift a parcelto its level of free convection is tested from the Convective Available Potential Energy andConvection Inhibition. This last parameter is compared against the mountain waves´ verticalkinetic energy. The time evolution and vertical structure of vertical velocity and equivalentpotential temperature suggest in both cases that the detected mountain wave amplitudes are ableto provide the necessary energy to lift the air parcel and trigger convection. A simple conceptualscheme linking the dynamical factors taking place before and during storm development isproposed.