Multiscale Processes Enabling the Longevity and Daytime Persistence of a Nocturnal Mesoscale Convective System

• DOI: 10.1175/mwr-d-18-0233.1
• Publication Date: 2018-12-18T21:01:25Z
• Authors: Manda B. Chasteen; Steven E. Koch; David B. Parsons
• Keywords: Mesoscale convective system; Convective inhibition

Abstract Nocturnal mesoscale convective systems (MCSs) frequently develop over the Great Plains in presence of a nocturnal low-level jet (LLJ), which contributes to maintenance by providing source instability, convergence, and vertical wind shear. Although these MCSs often dissipate during morning, many persist into following afternoon despite cessation LLJ with onset solar heating. The environmental factors enabling postsunrise persistence convection are currently not well understood. A thorough investigation processes supporting longevity daytime an MCS was conducted using routine observations, RAP analyses, WRF-ARW simulation. Elevated developed response enhanced frontogenesis, quickly grew upscale severe quasi-linear system (QLCS). western portion this QLCS reorganized bow echo pronounced cold pool ultimately organized leading-line, trailing-stratiform as it moved increasingly unstable environment. Differential advection resulting from interaction topography west Texas established considerable heterogeneity moisture, CAPE, CIN, influenced structure evolution MCS. An inland-advected moisture plume significantly increased near-surface CAPE nighttime central Texas, while environment southeastern abruptly destabilized commencement surface heating downward transport. unique southern plains close proximity Gulf Mexico provided conducive