Air quality alert, scattered thunderstorms Monday, Tuesday; cooler midweek

Minnesota seeing early run of 90-degree days

AQ alert update
Air quality alert through 12 a.m. Tuesday
National Weather Service

Monday will again be hot, humid and hazy with smoky skies. An air quality alert is posted for some areas through midnight. Look for scattered thunderstorms on Monday and Tuesday with cooler and drier air moving in for mid to late week.

Air quality alert; afternoon storm possible

An air quality alert has been extended for east-central, south-central, and southeast Minnesota into western Wisconsin through midnight Monday.

The culprit is both surface ozone, which is a reaction between sunlight and heat with pollutants and wildfire smoke. This time the smoke is coming from fires in eastern Canada versus western Canada in our previous episodes of smoky skies.

smoke plume
Current smoke plume and air quality sensors early Monday
National Oceanic and Atmospheric Administration

Check the latest air quality conditions and forecasts here:

Monday will be one last hot, muggy day with highs well into the 80s, close to 90 for some.

mon hi 8a
Forecast highs Monday
National Weather Service

A slowly moving blast of cooler and drier air will be creating a large area of instability with scattered showers and some thunderstorms possible Monday into Tuesday, especially in the afternoon periods.

mon-wed prec
Forecast precipitation 9 a.m. Monday through 4 a.m. Wednesday
NOAA, via Pivotal Weather

Tuesday will remain very warm and somewhat muggy with another chance of afternoon scattered thunderstorms.

tue hi 8a
Forecast highs Tuesday
National Weather Service

Cooler and drier air will finally settle in for mid to late week. Dew points will be dropping from the muggy 60s to the much drier 40s.

dews fcst
Forecast dew points Monday into Wednesday: big drop coming
NOAA, via Pivotal Weather

High temperatures Wednesday will be in the 70s for most to low 80s.

wed hi 8a
Forecast highs Wednesday
National Weather Service

The next chance of rain and thunder will move in late Friday into Saturday.

4 day fcst
Forecast for the week ahead
National Weather Service

Lots of 90s, very early

If you’ve been thinking it seems to be pretty consistently hot, very early, you’re right.

Sunday marked our fifth day in the 90s in the Twin Cities and Monday may make it six. It’s the third highest number of 90-degree days by June 5 since we’ve kept records. Only 1934 and 2018 beat this year.

90s rank
Ranking of the number of 90-degree days by June 5 since 1873; 2023 is No. 3
Sven Sundgaard, National Weather Service data

While one year or one heat wave can’t be blamed entirely on climate change, we’ve been seeing a noticeable trend of heat starting earlier in the summer and lingering later into September in recent decades.

We used to average about one day in the 90s by June 5, but that modern average is more like three. Summers are getting longer while winters are getting shorter, a sure signal of a warming climate.

90ds trend
Number of 90-degree days by June 5 since 1990 (left side being the most recent years, right side starting in 1990); trend line in red
Sven Sundgaard, National Weather Service data