Forecast Discussion

Current hourly ozone readings are in Code Yellow range across parts of the Piedmont and Inner Coastal Plain. Ozone is running a bit higher so far today so we have bumped numbers up to account for this. Daily averages of fine particulates are in Code Green range statewide.

On Thursday, the state will be post-frontal and on the backside of an upper-level low with a stiff northwest wind advecting in cooler and cleaner air. Daily averages of fine particulates are expected to drop well into Code Green range. With a cleaner airshed, along with strong winds and mixing leading to adequate dispersion, maximum 8-hour averages for ozone are expected to be in Code Green range.

The upper-level low will depart on Friday and we'll see rising heights as ridging begins to take shape over the state. At the surface, high pressure will be over the state and will be centered offshore, bringing southerly winds back into the state. This will lead to increasing fine particulates through the forecast period, although averages are expected to remain in Code Green range. As for ozone, temperatures are expected to rise into the upper 80s to low 90s as the ridge builds in. Coupled with sunshine and relatively dry airmass, we can expect ozone to increase each day, with Code Yellow maximum 8-hour averages forecast for all of the major metro areas by Saturday.