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CONVECT is focused in north-central Arizona between the cities of Prescott and Flagstaff. This targeted region, encompassing the Bradshaw Mountains, Black Hills, Verde and Prescott Valleys, and Mogollon Rim, provides an ideal laboratory for investigating processes connecting complex terrain to boundary-layer and convective processes. During the summer monsoon season, this region experiences frequent deep, precipitating convection. These storms typically initiate over the most prominent terrain features and sometimes propagate into the populated lower-lying areas or send out density currents or buoyancy bores that subsequently initiate new convection. The thunderstorms are generally spatially localized, forming over a deep convective boundary layer, but are often associated with pulse-severe conditions (damaging wind gusts or large hail). Some cells may become terrain-locked or exhibit back-building behavior, leading to intense rainfall and flash flooding.

CONVECT will also examine the water vapor sources and land-atmosphere interactions favoring convective initiation. Our previous work has shown that soil moisture is an important predictor of monsoon convection. We will therefore examine the effects of soil moisture variability on surface and PBL energy and moisture exchange over heterogeneous, sloping surfaces within a thermally driven planetary boundary layer (PBL). The proposed deployment includes a dense network of surface flux and energy balance probes, lower-tropospheric thermodynamic and kinematic profiling systems, mobile radars, and crewed and uncrewed aircraft with in-situ and remote sensors. The campaign will be carefully guided by multi-scale modeling and our machine learning model, and in turn, experimental observations will be assimilated to evaluate their impact on multi-scale predictability and the validity of surface layer and PBL parameterizations in complex terrain. The CONVECT science team of instrument scientists and numerical modelers contains the necessary, complementary expertise in the surface layer, the boundary layer, and deep convection to substantially advance understanding of water vapor exchanges between the surface and free troposphere, as well as extreme precipitation. The broader impacts will be improved forecast accuracy during the North American Monsoon by identifying improvements in operational instrumentation networks and forecast model parameterizations.