Light icy mix overnight; air quality alert into Thursday

Check the sidewalk closely before you venture out Wednesday morning.

A light icy mix overnight may be just enough to ice up sidewalks, driveways and some roads by early Wednesday morning. The thickest glaze will favor southeast Minnesota, Iowa, and Wisconsin. But the Twin Cities may get in on the light snow and icy coating.

Wintry mix

The low-pressure system passing through Iowa is fairly weak. But it doesn’t take much glaze to mess up driveways. parking lots, and sidewalks. A warm layer of air aloft across the Upper Midwest drives mixed precipitation overnight.

Slips and falls

We rightfully focus on roads and traffic conditions in winter. But any hospital ER professional will tell you the lobby fills up quickly with slip and fall patients after even a light glazing. Here are some common sense tips on how to stay vertical this winter.

Image courtesy of Insurance Bureau of Canada.

Air quality alert

It was nearly 50-degrees five-thousand feet above the Twin Cities today. That temperature inversion aloft combined with light winds is trapping pollutants near the ground. That means we’re breathing fine particulates that can be harmful. The MPCA air quality alert is in effect until 6 pm Thursday. Westerly breezes due in Thursday night should mix out the atmosphere, and improve air quality.

MPCA

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for the Twin Cities and portions of central Minnesota, effective 2 p.m. Tuesday, December 11th through 6 p.m. Thursday, December 13th. The affected area includes the Twin Cities metro, Willmar, and Hutchinson.

Fine particles have risen into the Orange (Unhealthy for Sensitive Groups) category in the Twin Cities metropolitan area this morning due to stagnant weather conditions. Light winds, clear skies, and a strong inversion have resulted in poor dispersion and air pollutants becoming trapped near the ground.

Poor dispersion conditions will continue over the next couple days as this plume of fine particles will slowly transport into central Minnesota. Fine particle levels in the alert area are expected to remain near or above 100 AQI until Thursday afternoon, when a front moves across the state and brings cleaner air into the region.

Mild into next week

Thursday’s breezes will finally blow milder air into Minnesota. Highs above freezing look likely into next week.

A few models hint at 40-degrees in the Twin Cities next week. We’ll see. But no bitter arctic fronts are on the maps for the next 1-2 weeks. A couple model runs hint at snow potential on Christmas Eve.

NOAA via Weather Bell.

Stay tuned.