What can we expect this ozone season?
Chris Brame, Weather or Not deputy operations manager, shared an outlook during a recent MARC Air Quality Forum. Weather or Not partners with MARC to provide air quality insights and forecasts throughout the season.
Ozone season in the Kansas City region started March 1 and runs through Oct. 31. Brame said Weather or Not uses historical analysis of years with long-term weather patterns similar to current conditions when compiling the outlook. The years closely matching current weather patterns and climate are 1991, 1972, 1965 and 1957.
“Most of these seasons, as a whole from May through October, ended up being near normal for both temperatures and precipitation,” Brame said. “Historical perspective of analog years gives us a best match insight into what the ozone season holds. We take those analog years and build a forecast process off of that.”
Brame said he expects April through June to have unseasonably mild temperatures punctuated by active weather patterns.
“The possibility of some early season [ozone] exceedances is there because of the warmer temperatures. But, at the same time, the active weather pattern will also get systems to move through; cold fronts bringing us cooler, dryer air and cleaner air, as well,” Brame said. “It’s kind of a give-and-take type of pattern through early to mid-June.”
According to the Environmental Protection Agency, an ozone exceedance for ground-level ozone occurs when ozone concentrations are greater than 70 parts per billion over the course of eight rolling hours per 24 hours in a day.
Brame expects July through August to continue having above-average temperatures while the region shifts into below-average precipitation, ideal conditions for Ozone Alert days.
“With these warmer temperatures in place … over the middle part of the country, it’s going to subdue our rain chances and will lead to, probably, a less active pattern. And that combination of warm air, hotter temperatures in the peak of the ozone season, with dryer and calmer conditions, that’s a recipe for potentially a larger number of exceedances,” Brame said.
The pattern is expected to flip in September and October. Brame said cooler temperatures and periodic rain showers will help keep the end of the ozone season calm.
“As we go through the rest of the summer and the end part of the season … there are no real red flags for us,” Brame said. “We’ll be looking at some below-normal temperatures trying to work back into the region going into late summer, early fall. This should provide the seasonal average of near-normal precipitation and rainfall.”
Stay informed about air quality this ozone season by receiving the daily SkyCast. The air quality SkyCast is issued daily at 4 p.m. Like a weather forecast, SkyCast provides the air quality conditions expected for the next day and issues an Ozone Alert when an unhealthy amount of ground-level ozone pollution is anticipated. Sign up for SkyCast.