The MODIS Terra image below (top left) shows areas of elevated AOD over the Great Lakes Region and Northern Canada, presumably from the light to heavy smoke originating from the NW Territories wildfire complex (HMS Google Earth image, top right). Remnant smoke from these wildfires last week loomed over most of the US. Today, the smoke surface concentration seems to have decreased except over the Great Lakes region and some areas in the central US. The low pressure system observed in today's NOAA Weather Map (bottom left) is most likely causing the aerosol mixing in the atmosphere, leading to healthier AQIs over much of the Eastern and central US.
Today's EPA AirNow forecast shows a spot of Unhealthy AQIs over central California, which eventually leveled to Moderate around 10:00 EDT. Another spot of Unhealthy AQIs popped up in central Washington around 12:00 EDT. The AQI for PM2.5 reached 170 in Leavenworth, Washington at this time, predicted to have been 64 - 128 ug/m^3 of smoke by the NAAPS Aerosol Model above (bottom right). USG conditions resurfaced in the same spot where the Unhealthy AQIs were noted in central California around 12:00 EDT. The HMS image above shows fires in this area with barely any visible smoke originating from them. The two new wildfires (both developed over the weekend) are the Sand Fire and El Portal and Dark Hole Fires, both reportedly still burning. In other news, a large dust cloud (presumably Saharan dust) is predicted by the NAAPS model to be traveling up the Caribbean, covering much of the Caribbean Islands and Central America. The MODIS Terra image above picks up high AOD levels over this area, just below Florida. Dust also seems to be a problem in the central US, predicted to reach 2.58 - 5.12 mg/m^3 over central Colorado. Lidar observations at UMBC show a homogeneous boundary layer through most of the day. Clouds advected during the early evening hours, and they extended from 1.5 to 5 km. The intense and short lived streaks for scatters is due to rain.