Forecast Discussion

Current hourly ozone readings are in Code Yellow range across parts of the Piedmont and southwestern Mountains. Current daily averages for fine particulates are mostly in Code Green range. However, there are several wildfires still burning in Polk County and daily averages for fine particulates are likely much higher in Polk County near and downstream of the wildfires where smoke is more concentrated. There is also smoke impacting Transylvania, Henderson, and Buncombe counties as well and fine particulates are likely elevated there.

As of Sunday afternoon, several wildfires continue to burn in Polk County and the two largest fires (Deep Woods and Black Cove fires) are over 1,100 acres each and 0% contained. Satellite imagery continues to show plenty of smoke coming from the fires. Also, two new fires just across the NC/SC border in SC began Saturday and are producing alot of smoke that is being sent northward into Transylvania, Henderson, and Buncombe counties. Inversions are expected tonight across the area and south-southwest winds should lessen in the valleys into Monday morning. This should lead to smoke sticking around and elevated PM2.5 values. A cold front will approach the area Monday morning and will likely move through midday. There may be some scattered showers ahead of and along the front, but models show much of this precipitation weakening as it comes across the mountains. It is possible that these scattered showers actually drag some smoke down to the surface and elevate PM2.5 values even more. Behind the front, winds will turn out of the northwest for the rest of the day. This will push smoke towards the southeast late in the day. With smoke impacting Transylvania and Henderson counties now through midday Monday and leading to hourly values that are likely at least Code Orange or higher, we are issuing Code Orange Air Quality Action Day Alerts for those counties through Monday night at midnight. We are also extending the Code Red Air Quality Action Day for Polk County through Monday night at midnight and the same for the Code Orange in Rutherford. For Rutherford, Transylvania, and Henderson counties, the worst air quality will be now through midday Monday, with the passage of the front helping to gradually improve air quality later Monday.

Monday's front should help bring a slight drop in pollutants on Tuesday, although a return of southerly flow may lead to low Code Yellow PM2.5 averages in the western part of the state. Another weak cold front will pass through late Tuesday and that should help lower pollutants a bit more on Wednesday. Expect more Code Green averages by midweek. For Polk County and surrounding counties, degraded air quality will continue for at least the next couple of days with Code Yellow or higher PM2.5 averages.