Warm south but cool north; air quality alert includes the Twin Cities

We hit 91 degrees on Thursday at Minneapolis-St. Paul International Airport.

The Twin Cities metro area has now seen 90 degrees or warmer on 11 days this year, which is right at our 30-year average for the number days per year that we reach 90 or warmer.

We could see a high of 90 degrees late Friday afternoon in the Twin Cities.

Temperature trends

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Friday highs are expected to range from the 60s in northern Minnesota to the upper 80s and a few 90 degree readings in the south.

On Saturday, highs are expected to range from the 50s northwest to the 80s southeast:

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On Sunday, we're expecting highs in the 50s in far northern Minnesota, then mainly 60s with a few spots in the Twin Cities metro area and southeastern Minnesota reaching 70:

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Twin Cities highs are expected to reach the lower 70s Monday, then upper 70s Tuesday and lower 80s Wednesday.

Air quality alert

The Minnesota Pollution Control Agency has issued an air quality alert from noon to 8 p.m. this Friday for the Twin Cities metro area and much of the southern half of Minnesota:

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Minnesota Pollution Control Agency

According to the MPCA:

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for southern, eastern and portions of central Minnesota, effective Friday, Sept. 15 from 12-8:00 p.m. The affected area includes the entire Twin Cities metro, Marshall, Rochester, St. Cloud, and the Tribal Nation of Upper Sioux.

The AQI is expected to climb into the orange (unhealthy for sensitive groups) category Friday due to unseasonably warm temperatures, mostly sunny skies, and high ozone levels moving in from the southern and central US.  AQI levels should start out in the yellow (moderate) category Friday morning, before climbing into the orange category during the afternoon and evening. Conditions are expected to improve around sunset Friday as ozone levels decline.

People whose health is affected by unhealthy air quality:  There are people who are more likely to be affected when ozone reaches an unhealthy level.

People who have asthma or other breathing conditions like chronic obstructive pulmonary disease (COPD), chronic bronchitis, and emphysema.

Children and teenagers.

People of all ages who are doing extended or heavy, physical activity like playing sports or working outdoors.

Some healthy people who are more sensitive to ozone even though they have none of the risk factors. There may be a genetic base for this increased sensitivity.

Health effects: Unhealthy ozone levels can aggravate lung diseases like asthma, emphysema, and COPD. When the air quality is unhealthy, people with these conditions may experience symptoms like difficulty breathing deeply, shortness of breath, throat soreness, wheezing, coughing, or unusual fatigue. If you are experiencing any of these symptoms use your inhalers as directed and contact your health care provider.

Take precautions: Everyone should take precautions when the air quality is unhealthy.

Take it easy and listen to your body.

Limit, change, or postpone your physical activity.

If possible, stay away from local sources of air pollution like busy roads and wood fires.

If you have asthma, or other breathing conditions like COPD, make sure you have your relief/rescue inhaler with you.

People with asthma should review and follow guidance in their written asthma action plan. Make an appointment to see your health provider if you don’t have an asthma action plan.

Pollution reduction tips: Ozone is produced on hot, sunny days by a chemical reaction between volatile organic compounds and oxides of nitrogen.

Reduce vehicle trips and fill-up the gas tank at dawn or dusk.

Encourage use of public transport, or carpool, when possible.

Postpone use of gasoline powered lawn and garden equipment on air alert days. Use battery or manual equipment instead.

Avoid backyard fires.

Rain chances

Western and south-central Minnesota will have the best chance of seeing some showers and thunderstorms on Friday, but scattered showers and thunderstorms could spread eastward Friday afternoon and Friday evening.

Periods of showers and thunderstorms are a good bet for most of Minnesota overnight Friday night, and they could linger over eastern Minnesota early on Saturday.

There could be a break in the action from mid morning on Saturday through early afternoon, then another batch of showers and thunderstorm from about mid afternoon into Saturday night.

The National Oceanic and Atmospheric Administration's North American Mesoscale forecast model shows the potential rain pattern Saturday and Saturday night:

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NOAA NAM simulated radar from 6 a.m. Saturday through 6 a.m. Sunday, via tropicaltidbits

The color chart to the right of the loop refers to the strength of the signal that returns to the radar, not to the amount of rain.

Severe weather outlook

The Storm Prediction Center of the National Weather Service shows a marginal risk of severe weather Friday and Friday night for much of western Minnesota:

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NWS Storm Prediction Center

Marginal risk means that an isolated severe thunderstorm is possible.

The severe weather risk shifts eastward for Saturday and Saturday night:

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NWS Storm Prediction Center

Parts of the Twin Cities metro area are included in a slight risk of severe weather Saturday and Saturday night, which means that scattered severe thunderstorms are possible.

The main threat for severe weather in the Twin Cities on Saturday would tend to be from late afternoon into the evening hours.

Florida power outages 

Hurricane Irma's damage to Florida's electrical grid is illustrated by these before and after images from NOAA:

A close up view:

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NOAA/NWS

The image on the right was taken before sunrise on Tuesday morning.

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Thursdays and Fridays, and at 7:35 a.m., 9:35 a.m. and 4:35 p.m. each Saturday and Sunday.