AGS-PRF: Daytime to Nocturnal Convective Transition in the Central United States

This award will provide funding for a postdoctoral researcher to study how the character of thunderstorms changes during the transition from day to night. During the day, thunderstorms feed off of the solar heating of the ground and are referred to as surface-based. When the sun sets and the ground begins to cool, the air flow into the thunderstorms becomes elevated and the thunderstorms often consolidate into a larger complex known as a mesoscale convective system (MCS). Computer models do not capture this transition well and forecasting of whether an MCS will form and how long it may survive becomes very difficult. This study will make use of both numerical modeling and observations to study the transition. The research should provide forecasters with more information about these hazardous nocturnal events which can contain severe winds and flooding rains. The researcher also would like to connect with other colleagues to determine how the public interprets forecasts for these types of events with an eye towards improving overall public safety.

The researcher plans to improve basic understanding of the dynamics of the nocturnal transition of convection through a series of numerical modeling experiments and analysis of high-resolution field observations. Two main research questions will be addressed: 1) How do increasing planetary boundary layer stability, increasing low-level jet strength, and increasing low-level lift along the terminus of the low-level jet influence upscale growth and behavior of convection during nocturnal transition and 2) Do field observations of nocturnal transitioning MCSs corroborate the results from numerical experiments? The researcher will perform idealized numerical experiments to address the first question and then follow-up with analysis of data from the Plains Elevated Convection at Night (PECAN) field campaign.