12B.1 Evolution of Thermodynamic Vertical Profiles from Pre- and Post-Convective Environments of Mesoscale Convective Systems Observed During PECAN

Thursday, 26 January 2017: 8:30 AM
Conference Center: Tahoma 3 (Washington State Convention Center )
Stacey M. Hitchcock, Colorado State University, Fort Collins, CO; and R. S. Schumacher, C. L. Ziegler, M. C. Coniglio, and M. D. Parker

During the Plains Elevated Convection at Night (PECAN) field campaign, 14 mesoscale convective system (MCS) environments were sampled by an array of instruments including radiosondes launched by three mobile sounding teams. Additional soundings were collected by fixed and mobile PECAN integrated sounding array (PISA) groups for a number of cases. Vertical profiles of the observed pre-convective environments can generally be grouped into 3 categories: 1) those with a shallow inversion, an elevated low-level region of maximum 𝛉e and a largely unstable layer up to 500 mb; 2) those that maintain a daytime-like planetary boundary layer (PBL) and are moist neutral above the boundary layer; and 3) those that are moist neutral through the mid-levels and have a region of mid-level instability. Post-convective soundings tend to be nearly completely moist neutral, or maintain an elevated region of maximum 𝛉e. The latter maintain sometimes up to 1000 J/kg of convective available potential energy (CAPE) despite the passage of a convective line, while the former range from minimal to a few hundred J/kg remaining CAPE.  This work will examine the evolutions of the pre-convective thermodynamic environments for a number of PECAN MCSs, and explore the relationships between the pre-convective environments and MCS intensity, organization, and the subsequent post convective thermodynamic environments.
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