As temperatures climb into the 90s — and could reach 100-plus degrees — starting Friday, the air quality in the Twin Cities metro and beyond is expected to worsen.
The high temperatures on Friday could also fuel wildfires, which has prompted the National Weather Service to issue a red flag warning and fire weather watch for much of central and northern Minnesota.
Here's what you need to know:
Air quality alert
The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for much of the Twin Cities and parts of east-central Minnesota, effective from noon to 9 p.m. Friday.
Here's a map of impacted counties:
The MPCA says air quality index values are expected to reach the "orange" or "unhealthy for sensitive groups" category on Friday.
Friday's sunny skies, hot temperatures, low humidity and light winds will "produce an environment favorable for emissions of nitrogen dioxide and volatile organic compounds near the Twin Cities that can quickly form ozone."
"Ozone concentrations will be the lowest in the morning hours Friday, will gradually rise midday, and peak in the late afternoon. Air quality will improve Friday evening."
People who are more likely to be affected when ozone pollution reaches unhealthy levels include people with asthma and breathing conditions like COPD, children and teenagers, people doing extended or heavy physical activity (playing a sport or working) outdoors, and some healthy people who have a genetic base of increased sensitivity.
Those who are affected by the air quality Friday may experience symptoms that include trouble breathing deeply, shortness of breath, a sore throat, wheezing, coughing and/or unusual fatigue. If you have an inhaler, use it as directed, and contact your doctor.
But even if you aren't at risk, MPCA says people should take precautions when the air quality is unhealthy by listening to their body; limiting, changing or postponing physical activity; staying away from pollution sources like busy roads and wood fires; and people with asthma should make sure they have an inhaler with them.
MPCA says ozone is produced on hot, sunny days by a chemical reaction between volatile organic compounds and oxides of nitrogen. To reduce this, people should reduce vehicle trips, fill-up on gas at dawn or dusk, use public transit or carpool, postpone mowing the lawn with gas-powered mowers and avoid backyard fires.
Red flag warnings
The steamy weather Friday that is making air quality bad in the metro is also providing perfect conditions for wildfires.
The National Weather Service has issued a red flag warning for northern Minnesota due to extreme fire risk conditions on Friday, meaning conditions — hot temperatures, low humidity and strong winds — are ideal for a wildfire, and any spark could become a wildfire.
During a red flag warning, people shouldn't burn anything and should check any burning done recently to make sure the fire is out.
The red flag warning is in effect from noon to 9 p.m. on Friday.
Portions of central Minnesota are also under a fire weather watch as the high heat and low humidity could create dangerous fire weather conditions Friday afternoon and evening for areas along and west of a line from Lake Mille Lacs to St. Cloud to Litchfield to Granite Falls. If wind speeds in that area increase, a red flag warning could be issued.
Current burning restrictions can be found on the Minnesota DNR's website here.
The hot weather is expected to continue into early next week. High temps are expected to be in the 90s and approaching 100 degrees through the weekend, with the NWS noting it may not get below 70 degrees Saturday night.
There is a marginal risk for severe thunderstorms Sunday afternoon.
The latest forecast from Novak Weather