Forecast Discussion

Current hourly ozone levels are in the Code Yellow range across most of the state. Current daily average fine particulate concentrations are in the upper Code Green to low Code Yellow range from Hickory to Raleigh, with lower values elsewhere across the state.

Tomorrow, an area of PVA will move into the region from the west out in front of a lifting upper level low over the Great Plains. A weak area of surface high pressure will build overhead. This weak high will push a backdoor cold front -- with cleaner air -- towards the northeastern corner of the state, but only a handful of counties from Warren to Halifax to Bertie north and east are likely to benefit as the front stalls and then lifts back north during the day.

Most numerical weather prediction (NWP) guidance generates significant high clouds across the state, which should slightly help temper ozone formation across the state. Still, with an aging air mass and some smoke across the region, expect ozone levels to rise into the low Code Yellow range in the metros. With high pressure overhead and increasing clouds, expect fine particulate daily averages to continue to rise into the low Code Yellow range across the interior.

Wednesday, similar synoptic pattern and air mass to Tuesday should result in similar conditions, with fine particulates likely to continue to elevate slightly. Thursday, as the aforementioned upper level low lifts into Canada, the attendant surface low -- also traversing southern Canada / the Great Lakes -- will drag a weak front towards the area. Weak high pressure building in behind the system will combine to try and shove the front through the state. Dependent upon if the front is able to clear the state, air quality may (or may not if the front is not able to clear the state) lower into the Code Green range. We will continue to monitor this and update the forecast based on trends.