FARGO — Forecasters expect unhealthy levels of air pollution from distant wildfires to dissipate in the Red River Valley by the end of this week, but it's likely that smoky skies will give way to sweltering heat.
WDAY StormTracker Meteorologist John Wheeler — who despite less-than-ideal conditions was out on a 25-mile bike ride on Thursday afternoon, July 15 — said a heat wave with temperatures possibly reaching the high 90s will start on Sunday or Monday and last through the week.
As for the air quality, he said it seemed a bit better Thursday afternoon.
"I'm fine," he said as he stopped for a break on his ride.
That wasn't what he experienced Wednesday night into Thursday morning, when his eyes burned and his throat got a bit sore on his walk home from work around midnight.
Daryl Ritchison, the director of the North Dakota Ag Weather Network based in Fargo, said the highest alert was lingering Thursday afternoon.
Air quality monitors in Fargo-Moorhead recorded some of the highest air pollution levels in the country Thursday morning as distant wildfires continued to fill the region's air with smoke.
Just before noon, the cities had reached an air quality index number of 184, well into the unhealthy air quality range, according to the U.S. Air Quality Index.
Unhealthy air quality levels mean some members of the general public may experience health effects, and more sensitive groups may experience more serious reactions to the pollution. The AQI scale starts at zero and reaches the hazardous level at 300.
Minnesota and North Dakota environment officials issued air quality advisories earlier this week, with Minnesota's warning covering the northern part of the state from the Red River Valley to the north shore of Lake Superior.
Minnesota officals on Friday extended the air quality warning through noon Saturday for areas including the Red River Valley. It was originally set to expire 9 a.m. Friday.
Around 3 p.m. Thursday, the air quality index number was still "very high and in the red zone" at 172, Ritchison said. Any number above 150 is in the unhealthy red zone, while an alert in the orange category is above 100 and considered unhealthy for sensitive groups.
However, with a light south wind blowing the smoke northward, it should be clearing out by Friday morning when the alert expires.
The air quality in Fargo-Moorhead is measured by a sensor on a tower found in north Fargo near County Road 20 and Interstate 29. It's one of three sensors in this region with others in Detroit Lakes, Minn., and the Red Lake Nation in northwestern Minnesota.
The Minnesota Pollution Control Agency records the measurements and issues the air quality alerts.
Wheeler said although Fargo technically may have had the worst air quality number in the nation on Wednesday night into Thursday, it was likely much worse near the wildfires burning across the northern Rockies, Pacific Northwest and northwestern Canada.
"There's no way we had the worst air quality in the nation," Wheeler said.
Smoke will be an issue throughout the summer as wildfires continue to burn, but it will usually remain in the high levels of the atmosphere where it won't hurt the quality of the air we breathe, Wheeler said. The hazy skies will create conditions for beautiful sunrises and sunsets, he added.
The expected heat wave would be the third time this summer that the Fargo-Moorhead area has experienced temperatures in the 90s for five days in a row, which is rare, Ritchison said.
Both Ritchison and Wheeler said the temperatures will likely be higher north and west of Fargo where it could reach into the triple digits.
Ritchison said it'll be a dry heat with lower humidity so it's unlikely that officials will issue heat index warnings.
Wheeler sees few chances for rain, although with the heat there could be scattered storms. It's not likely those would arrive until next weekend, he said.