MINNEAPOLIS (KMSP) - Its already begun, above freezing temperatures have started to pop up and do their thing on our January snowpack. From drips falling from the overhang to little rivers of snow melt running towards the storm drains, the icy grip has lessened, enough at least for Minnesotans to catch their breaths. The last time that the Twin Cities saw a stretch of upper 30s to near 40° was back in late November, so were due a break.
ITS ALL ABOUT THE JETSTREAM
The jet stream is way north of the Upper Midwest and will stay there through the week. This is allowing the milder and somewhat wetter air, from the south and west, to drift into Minnesota, the Upper Midwest and even parts of Canada. Enjoy!
THE THAW BRINGS BAGGAGE
Along with the warm up come a few inconveniences. Although the sun shines bright at the beginning, the moister from the melting snow combined with the wetter air mass, will make for a murky, foggy and cloudy time frame. It won’t be all fun in the sun with this thaw. A look at the model guidance for the next few days shows the increase in moisture. Look closely, you can see relative humidity values at 100% and a closer look shows temperatures and dewpoints almost identical. This friends is total saturation, resulting in fog, clouds and mist.
POLLUTION BUILDS UP
The warm air that moves in can also act as a lid and keep a stagnant layer near the surface that can fill up with pollution and lower the air quality. Our snowpack on the ground will constantly cool the air near the surface while the warm air moves in a lot. This pattern is upside down as the norm for the atmosphere is to get colder with height. There could be times when the pollution particles build up to unhealthy levels and result in some sort of an advisory. The link below provides the daily air quality forecast from the Minnesota DNR. https://www.pca.state.mn.us/air/current-air-quality-index