Forecast Discussion

Currently, hourly ozone and daily averages for fine particulates are running in Code Green range statewide.

A weak front will remain stalled across the state from southwest to northeast on Wednesday. To the south of the front (primarily I-95 to the coast, dew points will be higher and there will likely be more clouds and scattered showers and thunderstorms, especially later in the day. Air quality in this area should be in Code Green range again. To the north and west of the front, which covers the Piedmont to the Mountains, we may start to see some Canadian wildfire smoke filter in, which may be enough to bring daily averages for fine particulates into Code Yellow range. However, the most concentrated smoke should remain well north and west of our state. As for ozone, weak high pressure and ridging aloft should bring more stagnant conditions and lighter surface winds. There should be a decent amount of sunshine as well. Thus, Code Yellow 8-hour maximum averages for ozone are forecast for the Charlotte region as well as the Raleigh-Durham area. The presence of wildfire smoke may also lead to increased ozone formation.

The stalled front will begin to slowly drift northward on Thursday and by Friday should no longer be around. S/SW flow will be light on Thursday but will increase heading into Friday and a warm and very humid airmass will be in place statewide. This should lead to increasing clouds and scattered showers/thunderstorm chances. However, pinpointing areas that will see rain and those that will not is challenging. On Thursday, increased stagnation with light winds, along with sunshine and warm temperatures will likely lead to higher ozone averages in the Charlotte area, but the amount of clouds and rain is uncertain at this time. Fine particulates will likely pool across the Mountains and Piedmont Thursday but gradually decrease heading into Friday.