Shallow and Deep Convection Characteristics in the Greater Houston, Texas Area Using Cell Tracking Methodology

The convective lifecycle, from initiation to maturity and dissipation, is driven by a combination of kinematic, thermodynamic, microphysical, and radiative processes that are strongly coupled and variable in time and space. Radars have been traditionally used to provide the convective clouds characteristics. Here, we analyzed climatological convective cell radar characteristics to obtain and assess the diurnal cycle of shallow, modest deep, and vigorous deep convective cells that formed in the Greater Houston area, using the National Weather Service radar from Houston, Texas and a multi-cell identification and tracking algorithm. The examined dataset spans over four years (2018–2021) and for the warm season months (June to September). The analysis showed the clear diurnal cycles in cell initiation (CI), cell evolution parameters (e.g., maximum reflectivity, cloud top height, and the height of maximum reflectivity), consistent with the sea breeze circulation. The cell evolution is well represented by relationships between 1) the maximum radar reflectivity and its height, 2) the cloud top and the maximum vertically-integrated liquid, 3) the maximum reflectivity and columnar average reflectivity, and 4) cloud top ascent rate and cell lifetime. The relationships presented herein help to identify the cell lifecycle stages such as early shallow convection, vigorous vertical development, anvil development, and convective core dissipation. We also analyzed the near-storm environment to address any differences in the environmental conditions present at the time of CI and how they may differ between convective type (shallow, modest deep, and vigorous deep cells).