Foggy and smoggy with a side of snow

Upside-down forecast

The national weather maps Thursday look like a meteorological Rorschach test. Heavy snow in the south and east with light winds and a side of smog in Minneapolis?

Stagnant air

Our relatively peaceful El Nino winter comes with a catch. Big storms tend to steer south, and light steering winds mean more frequent stagnant air near the ground where we live. The result? Foggy mornings that can get icy, and trapped pollutants near the ground that reduce air quality.

The Minnesota Pollution Control Agency has issued an air pollution health advisory for Thursday.

St. Paul, Minn.-- The Minnesota Pollution Control Agency (MPCA) has issued an air pollution health advisory for central and southern Minnesota effective early Thursday morning through early evening of Thursday, January 21.

Air quality monitors indicate slowly-rising fine particle pollution values across the majority of the state of Minnesota. Overnight Wednesday, a combination of low clouds and fog and light southeasterly to easterly winds are expected to cause fine particle pollution to approach a level considered unhealthy. The peak will be during the morning rush hour and to continue into the late afternoon hours on Thursday, January 21. Much of central and southern Minnesota will be impacted. Conditions are expected to improve by late afternoon or early evening on Thursday when increased northwesterly winds begin to disperse pollutants.

An air pollution health advisory is issued when the AQI approaches but is expected to remain below 101, a level considered Unhealthy for Sensitive Groups. The MPCA issues an air pollution health alert when air quality is expected to reach and remain above that level.

At-risk Populations: Fine particle pollution is expected to be near a level considered unhealthy for sensitive groups. Populations sensitive to fine particles include those with preexisting cardiovascular or respiratory disease, the elderly, children, and individuals who participate in activities requiring extended or heavy exertion, both indoors and outdoors. Members of these groups are encouraged to postpone or reduce vigorous activity and minimize exposure to local sources of air pollution (i.e., heavy duty vehicle traffic, wood fires, and candles). Even individuals who are otherwise healthy may experience health effects when pollution levels increase.

Light snow later

Throw in a little shot of snow this afternoon and evening and roads could once again be icy in spots today.