Moderate (Code Yellow) PM2.5 AQI were observed today across Southwest, Southeast and Great Lakes states, with the most elevated concentrations, Unhealthy for Sensitive Groups (Code Orange), observed along the southern Texas/ New Mexico border (top left, courtesy AIRNow). According to the HMS analysis team, an area of light smoke was observed over the western Gulf of Mexico, believed to be remnants from the plethora of seasonal agriculture fires burning in Mexico/ Central America as well as the County Line fire in northeast Florida. Unfortunately, fair weather cumulus clouds persisted across Florida today and as a result obstructed satellite AOD retrievals. Nonetheless, air quality appeared to be improving throughout the afternoon after only a few morning AQI observations in the Code Orange range. Further north, fires in western Virginia continued to burn. The HMS analysis team reported plumes of light smoke from these fires traversing northeast this afternoon,
and MODIS imagery indicates elevated AOD around the region (top right). Elevated layers aloft were also observed by ELF today over UMBC (bottom left). It is possible the layers are from the Virginia smoke as a high pressure system offshore the Mid-Atlantic coast initiated southwesterly flow across the Baltimore-Washington corridor this afternoon. NOAA's HYSPLIT backward trajectories also allude to the layers originating near western Virginia.