Hypotheses for the development of MAHTE include a relative decrease in dew point within the ambient environment over time due to entrainment of dry air from above the CBL, and an enhancement in surface moisture fluxes near the leading edge of the outflow airmass. However, these hypotheses are difficult to test due to the small horizontal scale of MAHTE relative to the spacing of ASOS and other fixed observational platforms. High spatial and temporal observations of MAHTE development and evolution were obtained on 15 July 2019 using the Central Michigan University mobile mesonet. A series of north-south transects were performed from ~1730-0000 UTC ahead of developing storms, through fresh outflow where both temperature and dew point were lower than in the ambient environment, following transition of the outflow into a MAHTE, and during MAHTE evolution into the evening. At its most pronounced state, theta-e was 10K higher than in the ambient environment, due to a ~4°C higher increase in dew point and a ~2°C decrease in temperature when crossing the gust front. A gradual decrease in dew point in the ambient environment from 21 to 18°C to over the course of the afternoon supports the entrainment hypothesis for MAHTE development. These and other observations of the evolution of thermodynamic and kinematic properties within the outflow and ambient environment will be discussed in the context of ASOS, radar, satellite data, and other operational data.