A gradual increase in temperatures was seen in locations along the path of the polar vortex. Air quality news continues to focus in the western United States, particularly in central/southern California. PM2.5 concentrations in this region reached Code Yellow to Red AQI levels, as indicated in the EPA Airnow animation below. The right top image is a PM2.5 timeseries for some California Air Resources Board (data available in airnowtech.org) which reported max concentrations that ranged between 42-108 ug/m3. Haze associated with this air quality episode is shown in the webcam image from the US Forest Service Cucamonga South webcam. Time stamp on image is local time. Clouds are also shown above this haze layer hindering satellite AOD retrievals along this region.