Tuesday, June 27
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TOPAZ data were recorded from 09:17 - 20:13 PDT. 

Normal temperatures today (max. of 42 C at the lidar site) and 106 F at the NLVA NWS tower. Clear skies all day, with some suspended dust in the lowest 500 m during the morning.  A thin aerosol layer (with no ozone enhancement) of possible fire origin was also present around 2 km agl in the morning. The normal morning NW winds were light, but the afternoon SW winds increased to about 10 m/s. A layer of high ozone with very low aerosol of probable UT/LS origin was present above 4.5 km agl for much of the day, but disappeared around 1600 PDT with no obvious entrainment by the ML, which only reached to about 3.6 km agl. Surface ozone peaked at about 65 ppbv around noon, but decreased as the ML expanded and the surface winds increased.