Smoky skies continue Friday; air quality improves gradually by Saturday

Canadian wildfire smoke covers most of the Midwest this week. The thickest smoke lingers over Minnesota through Friday. The statewide air quality alert continues until 5 p.m. Saturday.

Check out the coverage of unhealthy air (red) across the Midwest Thursday afternoon. Thick smoke has drifted all the way south into central Illinois southeast into eastern Iowa and Michigan.

The worst of one of the longest smoke events on record in will be with us through Thursday night and Friday.

On the map below, the National Oceanic and Atmospheric Administration’s High-Resolution Rapid Refresh model near-surface smoke density shows the thickest smoke swirling overhead Friday with some easing by Saturday.

Southerly winds will begin to blow on Saturday, but with smoke penetration so far to our south we’ll actually recycle some of that smoke so improving air quality will be gradual process.

Here’s the Minnesota Pollution Control Agency’s forecast discussion:

KEY MESSAGES: 1) Air Quality Alert in effect for all of Minnesota. 2.) Periods of heavy surface smoke to impact Minnesota through at least Saturday. DETAILED DISCUSSION: Northerly flow on the east side of high pressure over southern Canada will continue steering wildfire smoke from central Saskatchewan and Manitoba southeast towards and/or into Minnesota through early today (Thursday), and surface high pressure will help keep the smoke at the surface. Smoke will continue drifting south and west to reach all parts of Minnesota. Surface high pressure will camp out over the region through Friday, and result in light winds and poor dispersion. Therefore, smoke may remain over the state until at least Saturday when winds finally switch from the south. Red/Unhealthy AQIs are forecast through the day Friday. Winds will switch out of the south over the weekend as high pressure drifts east of the area. Smoke concentrations should gradually decline, but with smoke spreading as far south as Tennessee and Missouri the clearing of the smoke may be slow. Orange AQIs could hang on into part of Sunday, but by Monday most of the smoke should push north back onto Canada. For ozone, thick smoke will hold back ground-level ozone production for today. For Friday and over the weekend, the combination of thinning smoke and stronger sunlight reaching the ground may cause ozone to increase due to the presence of ozone precursors in the wildfire smoke.

Pleasant temperatures and humidity

In other weather news our temperatures and humidity will be very comfortable through the upcoming weekend. Highs in the 70s will persist through the weekend.

We’re drying out, too. Soggy farm fields and wet basements will get a chance to dry out into at least early next week.

Hang in there, Minnesota.