Impacts by Deep Convection on the Surrounding Environment: Observations and Model Analyses

Convective environments nearby deep convective storms were sampled during the Mesoscale Predictability Experiment (MPEX). Few previous studies have focused on the environment surrounding convective storms to explore how convection influences this environment. In particular, upsondes released in near-storm environments provide unique opportunities to evaluate convective-scale numerical weather prediction model capability and accuracy. The 28-May and 29-May 2013 convective events in Kansas, Oklahoma, and Texas will be the focus of this study. The events are modeled using a 36-member nested ensemble of the Weather Research and Forecasting Model (WRF). Observations are assimilated using an ensemble adjustment Kalman filter (EAKF) with the Data Assimilation Research Testbed (DART). 28-May included a cluster of thunderstorms in the Oklahoma Panhandle and southern Kansas that formed along a dryline. MPEX teams released upsondes downstream of the cluster at a variety of distances from the core convective region. Results show reasonable ensemble spread in upper-level wind shear in the downstream environment with an overall underestimation of shear magnitude. Changes in upper-level shear are seen within the anvil region and extend outward beyond the anvil. The impacts of these changes on subsequent convective activity will be analyzed. On 29-May, an MCS developed in the Texas Panhandle. MPEX upsonde teams sampled the downstream environment as well as the wake. Upper-level shear is enhanced within the line and wake regions. The area of enhanced shear is generally confined to the anvil region. However, upper-level shear ahead of the anvil region slightly decreases as the convective line approaches. These two cases help illustrate how deep convection alters the nearby environment and provides insights on the capability of convection allowing models to simulate these important environmental changes.