Observations of the Afternoon to Evening Transition Occurring Within the Southern Great Plains Severe Convective Environment

Each spring, the U.S. Southern Great Plains (SGP) hosts a wide variety of ingredients (e.g. moisture, shear, instability, and lift) relevant to deep, moist convection.  Tracking the spatiotemporal evolution of these ingredients is critical to understanding the initiation, maintenance, and demise of deep, moist convection.  In the case of the afternoon to evening transition (AET), changes to these ingredients can be quite significant.  Various investigators have found that during the AET, rapid increases in low-level shear and stability occur.  However, this model offers conflicting answers to the question of convective evolution.  While increases in low-level static stability during the AET may act to destroy deep convection, increases in low-level shear may promote the development and maintenance of updrafts.  Consideration of only these two ingredients offers an incomplete and conflicting conceptual model of how AET environmental changes may impact the behavior of ongoing deep convection.

Scientific literature has suggested an increase in low-level moisture (roughly 1 g/kg) also occurs around the AET time period, which we hypothesize can act to offset decreases in convective buoyancy caused by the accompanying increase in static stability.  This phenomenon has not been studied within the context of environments supportive of deep, moist convectionand may offer a more complete model of how the AET environment may impact deep convection.  To better characterize how these changes in low-level ingredients occur in during the AET, high-temporal resolution observations of low-level thermodynamic and kinematic quantities from an Atmospheric Emitted Radiance Interferometer (AERI), water vapor differential absorption lidar (DIAL), and Doppler wind lidar instruments collected during the Plains Elevated Convection at Night (PECAN) field experiment will be analyzed.