Forecast Discussion

Ozone readings are in the Code Yellow range in the western Piedmont and isolated areas of the Coastal Plain, with Code Green conditions elsewhere. Fine particle pollution readings are in the Code Green range statewide.

On Tuesday, high pressure will remain over the region. Sunny, dry weather will dominate the picture, and calm to light and variable winds in the morning will become steadier out of the north-northwest during the afternoon hours. Additionally, aerosol model guidance is hinting at some smoke aloft which could further enhance ozone formation if enough makes it down to the lower levels of the atmosphere. With that in mind, have issued a Code Orange AQI forecast for Mecklenburg and Union Counties. Low to mid-Code Yellow ozone AQI values are expected elsewhere in the state, but if there is sufficient afternoon sunshine AQI values in the upper Code Yellow range are possible in the Triangle. As the air becomes increasingly stagnated, fine particle pollution levels are expected to increase but with low upwind values, the daily AQI is expected to remain within the Code Green range.

High pressure will remain over the region on Wednesday, and fair, dry weather is expected to persist. Dewpoints are expected to rebound a bit into the low-mid 60s, buy may be sufficiently low enough to facilitate the formation of ozone when combined with light winds, sunny skies, and lingering smoke aloft. Overall, daily ozone AQI values in the Code Green range are expected over the Coastal Plain, with higher readings in the Code Yellow range over the interior. The highest values are expected in and downwind of the Charlotte are, where AQI values in the upper Code Yellow range are possible. By Thursday, a cold front will approach the region from the north-northwest. Increased cloud cover and chances for showers ahead of the front will help to improve air quality. Overall, the daily ozone AQI should remain within the low Code Yellow range over the Mountains and Western Piedmont, with lower readings in the upper Code Green range to the east. The daily fine particle pollution AQI is expected to maintain within the Code Green range through Thursday.