Air quality was particularity problematic again for the Pacific Northeast (top left). Code Orange, Pm2.5 levels were observed in central and Northwest Oregon today. Persistent poor air quality continued today across the San Joaquin Valley, peaking at Code Red (Unhealthy) levels. The fire in Oregon that Ray mentioned in yesterday's post is now being recognized by the Hazard Mapping and Fire and Smoke (HMS) analysis team (top right), however due to widespread cloud cover in the region, aerosol optical depth measurements are difficult to see (middle left). Elsewhere, the HMS team is reporting several fires throughout the Mid-West, Southern Plains and Southeast (middle right). Weather headlines have been very active over the past few days, as the nation braces for a widespread polar freeze from the "polar vortex"' weather phenomenon (aka powerful low pressure system over Canada dipping into northern USA). The National Weather Service hopes to prepare residents for the dangerously cold conditions by issuing widespread Wind Chill, Freeze, and High Wind Advisory and Warnings (bottom left). Much of the USA is already feeling the brunt of this mid- winter freeze, as temperatures approach record lows, dipping well below zero (bottom right). This significant weather event could be meaningful in terms of air quality, as millions burn fire wood for heat, there's a chance particulates from smoke in the atmosphere could rise.