Typical cold, dry winter air: Since last Friday (January 10), some of the coldest air of the winter has gripped portions of Minnesota, bringing low temperatures of -20°F or colder to many northern areas of the state. It was -25°F at Brimson (St Louis County) on January 15th. Of further note, forecast models suggest perhaps the coldest air of the winter will grip the state of Minnesota over the coming Saturday through Tuesday period, with some days never seeing the temperature reach zero. The polar air that descended upon us earlier this week was very dry, with dew points well below zero (-10 to -25°F). The drying effect of this air is greatly amplified when it is drawn inside buildings and then heated up to 68 degrees F, a typical indoor thermostat setting. For example, if you compute the partial pressure of water vapor (essentially the number of water vapor molecules) in outside air with a dew point temperature of -10 degrees F (like we had in the Twin Cities on Monday of this week...
Dry start to January with fluctuating temperatures: Most of the major storm systems so far this year have been south of Minnesota. Consequently, there has been little precipitation measured through the first 9 days of January. Most climate stations report no precipitation at all, but a few northern stations have reported a half inch to an inch of snow. The latest map from the DNR-State Climatology Office shows that about 70 percent of the state measures a snow depth of 1 inch or less as of Thursday, January 9th. Total seasonal snowfall accumulations are really lagging behind normal, as many areas of the state have reported less than 10 inches since November 1st . Only portions of northeastern Minnesota have reported total seasonal snowfall of 20 inches or greater, but that is still below normal for this time of winter. There is a chance for some snow this weekend, but not in abundant amounts, and certainly not in the quantity of the famous historic blizzard that occurred 50 years...