Forecast Discussion

Current hourly ozone readings are in Code Yellow range across parts of the Piedmont. Current daily averages for fine particulates are in Code Yellow range across portions of the Piedmont and southeastern Coastal Plain. 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.

As of Saturday afternoon, several wildfires continue to burn in Polk County and the two largest fires (Deep Woods and Black Cove fires) are over 1,000 acres each and 0% contained. Satellite imagery continues to show plenty of smoke coming from the fires. Weak high pressure will be over the state tonight into Sunday and inversions are expected to form along with weak to calm surface winds. This will once again lead to smoke being trapped and air becoming stagnant at the surface, thus leading to unhealthy air quality for everyone. Inversions will break later Sunday morning and winds will increase and turn from the south, which will push the smoke plume northward into western Rutherford County and beyond through the afternoon. With some smoke likely lingering tonight and then the main smoke plume likely moving through parts of Rutherford County for a stretch of time during the day Sunday, we are forecasting Code Orange in Rutherford County for another day. Henderson County may also see elevated fine particulates for a period of time Sunday as the smoke plume may brush the far eastern portion of the county. We are also watching a new wildfire in Burke County that began Saturday afternoon and have increased the forecast today and Sunday into Upper Code Yellow for Burke and Caldwell counties. Depending on how the fire evolves, we may consider increasing the forecast. As for the rest of the state on Sunday, a weak cold front that pushed through the state will move back northward as a warm front through the morning. Winds will then shift out of the south behind the front. This will likely advect in some fine particulates from the south and we should see Code Yellow averages for the western half of the state. As for ozone, Upper Code Green 8-hour maximum averages are expected, as enough wind and mixing should keep ozone dispersed enough and lowered weekend emissions should also lower ozone formation. Ridgetops out west will be the only exception and may finish in Code Yellow due to some advection of ozone and a strong inversion leading to elevated values overnight into Sunday morning.

A weak cold front will move across the state on Monday and should bring an increase in clouds and a chance for scattered showers. A strong southwesterly flow ahead of the front will advect fine particulates into the state and much of the state will be in Code Yellow range for daily averages. However, clouds and rain should keep ozone in Code Green range. The front may not clean the state out and we could see Code Yellow air quality again on Tuesday.