14.1 Environmental Thermodynamic and Kinematic Changes Caused by MCSs during PECAN

Thursday, 27 July 2017: 10:30 AM
Coral Reef Harbor (Crowne Plaza San Diego)
Russ S. Schumacher, Colorado State Univ., Fort Collins, CO; and R. Adams-Selin and S. M. Hitchcock

Mesoscale convective systems (MCSs) are known to alter their environments in numerous ways, some of which are obvious, like the generation of strong low-level cold pools, and others more subtle, such as ascent and descent in gravity waves propagating away from the system. These mechanisms can become even more complicated in nocturnal MCSs, which often encounter low-level stable layers and developing low-level jets. One of the goals of the Plains Elevated Convection at Night (PECAN) field campaign in 2015 was to better observe and understand the interactions and feedbacks between MCSs and their environments.

The quantity of vertical soundings collected during PECAN (approximately 1500 radiosondes, with 500 of those during MCS cases; numerous remote sensing instruments) allows for a thorough characterization of the MCSs observed during the project, including both their pre-convective environments and their subsequent influences. This presentation will focus primarily on changes to the thermodynamic and kinematic properties of MCS inflow that appear to be influenced by the MCSs themselves. Using PECAN sounding observations as well as numerical simulations—both available at very high temporal resolution—we will assess these modifications, and how they relate to the organization, maintenance, and evolution of the MCSs observed during PECAN.

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