According to the HMS analysis team, small areas of smoke were observed today adjacent to wildfires in the Northwest as well as a dense patch of agriculture fires in the North Dakota. A larger, narrow band of smoke stretching southward from Ontario through the Plain States and into eastern Texas was observed (top left, courtesy HMS). Furthermore, a surface cold front situated along the eastern side of the thin layer of smoke and may be acting as a boundary impeding its westward propagation for now (top left, courtesy NOAA HPC). Today's MODIS Terra RGB image overlaid with AOD and HMS Fire locations illustrates the broad swath of clouds associated with the frontal boundary and slightly elevated AOD west of the feature (bottom left). In terms of air quality, only scattered Code Yellow (Moderate) PM2.5 observations were recored across the Plain States, with a few areas also recorded across the Mid-Atlantic and Southeast states. Elsewhere, Code Red (Unhealthy) AQI levels were measured in the Pacific Northwest, as well as a broad region of Code Yellow and Orange (Unhealthy for Sensitive Groups) in California (bottom right,courtesy AIRNow).