Analysis of the environment of a severe hailstorm in Mendoza, Argentina during the RELAMPAGO-CACTI field campaign

HERNAN BECHIS; ALVAREZ IMAZ, MILAGROS; INES SIMONE; GALLIGANI, VICTORIA; MAITE CANCELADA; FRANCO PISCITELLI; MALDONADO, PAULA; SALIO, PAOLA

Conferencia; EMS Annual Meeting; 2021

Storms in the Mendoza province, Argentina are known for frequently producing large and severe hail. Theenvironmental conditions and strong interaction with topography there provide unique conditions for theinitiation and intensification of severe storms. The RELAMPAGO (Remote sensing of Electrification, Lightning,And Mesoscale/microscale Processes with Adaptive Ground Observations) and CACTI (Clouds, Aerosols, andComplex Terrain Interactions) field campaigns were deployed between October 2018 to April 2019 overwest-central Argentina, and have collected unprecedented Intensive Observation Periods (IOPs) in the region.During the IOP number 10 on November 26, 2018, a severe hailstorm developed and moved across theobservational network in the Mendoza domain. 4-cm diameter hail was reported over multiple hailpad sites andwith in-situ measurements. Several soundings, mobile and fixed radar observations, and surface observationsare available for this case, along with 1-min GOES-16 ABI Mesoscale Domain Sector (MDS) data coverage.high-temporal frequency soundings and surface observations collected prior to the convection initiation areanalyzed, allowing a detailed description of the storm environment. Processes leading to convective initiationover the higher terrain include the development of the upslope flow associated with a mountain-plainscirculation, the weakening and ascent of the nocturnal inversion owing to diurnal heating and mixed-layergrowth, and upper-level cooling related to the advance of a shortwave trough. Once the storm initiates, itmoves eastward towards the lower terrain, where the higher CAPE and deep-layer shear environment supportthe transition into a supercell. It is after this transition that the most severe hail at the surface is observed.