FORECAST SUMMARY: Friday, September 1, 2023, through Saturday, September 2, 2023
Ozone: 8-hour average Ozone concentrations are forecast to range between Good and Moderate.
PM-2.5: 24-hour average Fine Particulate levels are also expected to be in the Good to Moderate range.
FORECAST DISCUSSION: After the mid-week cooldown, temperatures will be on the rise as we move into the Labor Day weekend. Along with warmer temperatures, dry conditions are expected thanks to high pressure dominating. This set-up, however, brings with it the threat for increased ozone. On a positive note, southerly winds through the period should keep wildfire smoke plumes from coming into the region and influencing pollution levels.
High pressure east of Michigan is forecast to sink south over the weekend. This position gives us a southerly wind flow through the period which turns a bit more westerly Saturday as a weak/dry boundary moves in from the north. Warm temperatures west of us Friday move into the area during the weekend, increasing temperatures each day. Similar conditions are expected at upper levels with warm, southerly flow over the region.
For the ozone forecast, there is currently a low background in place and while readings are likely to increase Friday, 8-hour readings higher than low-Moderate are not anticipated. The boundary Saturday brings in a cloud layer which reduces chances for increased ozone. More widespread Moderate readings are forecast Saturday and there is a small chance a monitor may reach low-end USG, but this chance is low and would be isolated. Sunshine will be more prevalent on Sunday making it a better day for ozone conducive conditions. Because of this, there will be a forecast update Saturday morning to detail if conditions warrant an Action Day.
Like ozone, there is currently a low background of PM2.5 in place. Warmer conditions and southerly winds tend to increase PM2.5 levels, but stronger winds are forecast. Increased winds lead to more mixing that should keep PM2.5 readings Good to low-Moderate.
EXTENDED FORECAST: Extended models show warm, dry conditions lingering through the Labor Day holiday. With the threat for increased ozone continuing early next week, we will be doing daily updates to the air quality forecast until the threat ceases.
Next Forecast Update: Saturday, September 2, 2023