PM2.5 concentrations reached Code Yellow (Moderate) AQI levels in Southeastern United States, as an upper-level ridge of high pressure reduce vertical mixing in the atmosphere. PM2.5 was also Moderate in Oklahoma, California and Nevada. The weather system on the Southeastern US was also conducive to the Code Yellow ozone AQI levels due to sunny skies and temperatures in the mid-80s that enhanced ozone formation.
NOAA HMS reported dust off the coast of California. The dust led to the high MODIS Aqua AOD values retrieved over this region. The dust was visible inland as far as the Nevada border. The dust is Asian in origin and has been blowing over the Pacific the last few days. There are also a few plumes of smoke visible from several agricultural burns. Agricultural burns in Alabama and northwestern Florida are visible in MODIS Aqua RGB image, and are denoted with a red outline.
Lidar observations at UMBC show a homogeneous boundary layer extending up to 1.5 km. Clouds advected after 20:00 UTC (4:00 pm local time) at heights of 3-5 km. A thin particle pollution layer aloft was also observed at heights of 2.5-2.75 km.