Spatial, Seasonal, and Diurnal Variations of Convective and Stratiform Precipitation in the US

The Echo Classification from COnvectivity (ECCO) algorithm provides classifications of radar echoes in three-dimensional (3D) Cartesian grids. It separates radar observations into shallow, mid, and deep convective features, and low, mid, and high stratiform echoes. ECCO also provides convectivity, a quantitative measure of the convective or stratiform nature of precipitation, for each radar grid point in three dimensions. ECCO was applied to three years (2021-2023) of combined 3D reflectivity observations from the Multi-Radar/Multi-Sensor system (MRMS) over the continental United States.

We explore how convective and stratiform precipitation varies spatially over the US, and identify regions with significant occurrence of different types of precipitation. An investigation of seasonal and diurnal variations of 3D convective properties highlights, for example, the formation of deep convective systems over the Rocky Mountains in summer, their growth into Mesoscale Convective Systems, and their advection and ultimate dissipation over the Great Plains. Other observed phenomena include the diurnal cycle of convection over and around the Florida peninsula during the warm season, or high stratiform features over the Great Plains in winter.