Forecast Discussion

Current daily average particle pollution levels are still in the Code Red range in Wake County, although hourly levels have slowly lowered into the Code Orange range. Elsewhere, hourly concentrations from the Triangle north and east continue to run in the upper Code Yellow to low Code Orange range, with low values in the Code Yellow range elsewhere across the state. Ozone levels are rising into the low to mid Code Yellow range across the southern and eastern halves of the state.

Tomorrow, H5 cutoff upper low trapped over New England will finally begin to lift northward, ending the prolonged northwesterly upper level flow event that has transported all of the Canadian wildfire smoke into the eastern U.S.

Remnant smoke over the Ohio Valley will rotate across the Mid-Atlantic tomorrow, which along with the large swath of elevated PM2.5 concentrations upwind will lead to another day of elevated particle pollution concentrations. We are currently projecting upper Code Yellow, although some hourly concentrations -- especially overnight -- could be in the Code Orange range. Will continue to monitor trends overnight and adjust the forecast if needed to account for the latest trends.

Sunday into Monday, several upper disturbances to the west will result in unsettled conditions during the period. Clouds and rain are expected to move in from west to east on Sunday afternoon ahead of a digging shortwave. On Monday, another cutoff low will strengthen over the Ohio Valley region, continuing to promote southwesterly flow aloft along with PVA, which will likely continue to result in clouds and showers that should hold air quality levels predominantly in the upper Code Green range.