Influence of Bores on Nocturnal Convective Initiation During PECAN and on the Canadian Prairies: A Case Study Analysis

PECAN 2015 (Plains Elevated Convection at Night) set out to advance our understanding of continental, nocturnal warm-season convective precipitation through a dedicated field project in the central U.S. Two of the research foci for PECAN included the processes involving: 1) nocturnal elevated convection initiation (NECI), and 2) the origin and formation of bores and wavelike disturbances. It was observed during PECAN that bores and other wave like disturbances were quite common and often initiated nocturnal thunderstorms. Mixing processes involved with the passage of a bore or solitary wave have been shown to cause impressive changes to the lower tropospheric profile in previous studies. These changes can also destabilize the lower troposphere and create a more favorable environment for NECI brought on by mixing and upward displacements of air parcels from the passing bore. The goals of this research are to: 1) further examine the thermodynamic changes associated with bores within and above the stable nocturnal boundary layer, 2) identify different atmospheric environments where bores may lead to further NECI, 3) examine the occurrence of bores on the Canadian Prairies, and 4) contribute to developing a methodology for forecasting bore potential based on previous research. These research goals will be addressed through the use of data collected by a wide range of remote sensing instrumentation used during PECAN and in southern Manitoba for select case studies. High-resolution model runs are also conducted on several PECAN and Canadian Prairie cases to further examine bores using the WRF-ARW model.