Foggy and smoggy with a light icy mix overnight

A strong temperature inversion and light winds are is causing the worst winter air quality since 2005 in the Twin Cities.

A strong warm layer about 5,000 feet above ground level and light winds are trapping pollutants near the ground where we breathe.

Additionally, snowmelt can provide a favorable environment for fine particulates to hang in the air. Fine particulate readings on air quality monitors have now reached the unhealthy range at 161 ppm for the Twin Cities and much of southeastern Minnesota Tuesday afternoon.

That’s why the Minnesota Pollution Control Agency has extended the air quality alert for much of Minnesota until 6 p.m. Wednesday.

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for central and northwestern Minnesota. The alert takes effect Tuesday, Jan. 10, beginning at 11 a.m. and runs until Wednesday, Jan. 11, at 6 p.m.

Light winds combining with moisture from melting snow will trap fine particulate pollution near the surface in central and northwestern Minnesota.  Air quality will improve Wednesday with the arrival of a cold front, causing the fine particle pollution to disperse.

Fine particle levels are expected to reach the red air quality index (AQI) category, a level considered unhealthy for everyone, across far western Minnesota and parts of the Twin Cities Metropolitan Area. This area includes Minneapolis, St. Paul, Bloomington, Prior Lake, Richfield, Eagan, Apple Valley, Lakeville, Moorhead, and the tribal nation of Prairie Island. In the red area, all individuals should avoid prolonged outdoor exertion.

Fine particle levels are expected to reach the orange air quality index (AQI) category, a level considered unhealthy for sensitive groups, across northwestern and central Minnesota. This area includes St Cloud, East Grand Forks, Alexandria, Brainerd, Hinckley and the tribal nations of Upper Sioux, Leech Lake, Red Lake, and Mille Lacs. Fine particle levels are expected to be in the orange AQI category, a level that is considered unhealthy for sensitive groups, for far southern and northeast Minnesota. In the orange area, sensitive groups should avoid prolonged time outdoors.

A dense fog advisory covers most of southwestern Minnesota until 6 p.m. Tuesday night.

Including the cities of Morris, Madison, Benson, Montevideo, Granite Falls, Olivia, Redwood Falls, New Ulm, and St James

1137 AM CST Tue Jan 10 2023

...DENSE FOG ADVISORY NOW IN EFFECT UNTIL 6 PM CST THIS EVENING...

* WHAT...Visibility one quarter mile or less in dense fog.

* WHERE...Portions of south central, southwest and west central Minnesota.

* WHEN...Until 6 PM CST this evening.

* IMPACTS...Hazardous driving conditions due to low visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS... If driving, slow down, use your headlights, and leave plenty of distance ahead of you.

Light icy mix overnight

In addition to the fog and smog, a weak weather system will produce a little light icy precipitation mix across central Minnesota including the Twin Cities area overnight.

The latest forecast model trends favor more light icing, with a little snow possible into Wednesday morning. The National Oceanic and Atmospheric Administration’s NAM 3 km resolution model paints patchy mixed precip overnight into Wednesday morning:

The latest forecast model trends suggest a minor system with light ice and probably less than an inch of snow in most areas.

It doesn’t take much ice to cause slick roads and walkways, Take care as you travel overnight through Wednesday morning!