Typical cold, dry winter air:

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), then assume with no additions or subtractions of water vapor molecules, you draw that air inside your home or office (via opening a door for example) and heat it up to 68 degrees F. At this temperature, the air can hold a decidedly larger number of water vapor molecules than the cold air outside, therefore the relative humidity declines rapidly to only 4 percent. That alone leads to dry mouth, lips, skin, raspy voice, nose bleeds, itchy scalp and skin and static hair, etc. Indoor plants, humidifiers, or vapor discharge from showers, washers, and clothes driers really help to improve the indoor relative humidity, but they rarely raise it above 45-50 percent in the wintertime. Notice too that condensation on bathroom or locker room mirrors after bathing or showering, will disappear much faster than normal when such dry air is present.

Weekly Weather Potpourri:

This week’s AGU-EOS Bulletin has article documenting the exceptional global warmth of 2024. For many areas of the globe, both continental and oceanic it was the warmest year of record. “Not only was 2024 the warmest year when averaged across the globe, but it was the warmest year at the local scale, too. Scientists at Berkeley Earth calculated that 32% of land areas and 21% of ocean areas had the warmest year on record for the region.”

This week, the Weather Underground web site feature a review article about the weather of past Presidential Inaugurations in the USA. This year, Inauguration Day will be on Monday, January 20th and the weather is expected to bring the coldest Inauguration in 40 years, with an expected temperature in the upper teens to lower 20s F. This will be the coldest since the 2nd Inauguration of President Ronald Reagan in 1985 when it was just 7°F. Before 1933, the Presidential Inauguration was set for March 4, but even March weather in Washington D.C. brought many trials and tribulations, which are reviewed in this article.

A new article in the journal Science quantifies the increased frequency of multi-year droughts globally as a result of climate change. An increased frequency of such droughts is observed since 1980. Temperate grasslands have experienced the largest declines in vegetation due to these multi year droughts.

MPR listener question:

Looks like Thursday and Friday of this week will bring an official January Thaw to many parts of the state. We are wondering if there has been a change in the frequency of January Thaws (more) with the impact of climate change in Minnesota? Thought you might know.

Answer:

Yes. After many reports of subzero temperatures earlier this week around the state, both Thursday and Friday are expected to bring daytime highs from the mid 30s F to low 40s F. This meets the definition of a January Thaw according to the MN-DNR-State Climatology Office (“A January Thaw is defined as two or more consecutive days with maximum temperatures above 32 degrees F”). In fact, Madison (Lac Qui Parle County) reported a high of 43°F and Canby (Yellow Medicine County) a high of 42°F on Thursday (January 16) this week, after reporting lows of -10°F and -11°F just two days before.

For the Twin Cities the historical frequency of having a January Thaw is about 83 percent, and since the near historic cold of January 1982, the frequency has been 93 percent. For Morris (Stevens County) of western MN, the historical frequency of a January Thaw has been 86 percent, and near 90 percent since the historic cold January of 1982. Further north at Pokegama Dam (Itasca County) the historical frequency of a January Thaw has been just 66 percent with little change in frequency.

Some of the increased frequency in the January Thaw may be due to climate change, as many portions of southern and central Minnesota no longer have the same historical persistence of snow cover (an amplifier for cold temperatures) during the month, while locations such as Pokegama Dam and further north have been able to maintain persistence of January snow cover, even in the presence of climate change.

Twin Cities Almanac for January 17th:

The average MSP high temperature for this date is 23 degrees F (plus or minus 14 degrees F standard deviation), while the average low is 8 degrees F (plus or minus 15 degrees F standard deviation).

MSP Local Records for January 17th:

MSP records for this date: highest daily maximum temperature of 44 degrees F in 1894; lowest daily maximum temperature of -12 degrees F in 1962; lowest daily minimum temperature of -26 degrees F in 1967; highest daily minimum temperature of 35 degrees F in 1876, and record precipitation of 0.90 inches in 1996. Record snowfall is 5.1 inches in 1932.

Average dew point for January 17th is 5°F; the maximum dew point on this date is 39°F in 1973 and the minimum dew point on this date is -37 degrees F in 1962.

All-time state records for January 17th:

The state record high temperature for this date is 58 degrees F at Winona (Winona County) in 1889. The state record low temperature for this date is -54 degrees F at Embarrass (St Louis County) in 2005. The state record precipitation for this date is 2.20 inches at Byron (Olmsted County) in 1996. The statewide snowfall record for this date is 15.0 inches at Fort Ripley (Crow Wing County) in 1870.

Past Weather:

A very warm January 17th prevailed across Minnesota in 1894. Observers in 16 counties reported afternoon high temperatures of 40°F or greater, and 4 counties saw daily highs of 50°F or more. Overnight lows remained above freezing in the Twin Cities area with little or no snow cover.

Record setting cold temperatures prevailed across Minnesota on January 17 of 1982. With 10 to 20 inches of snow cover, even daytime highs remained subzero in most places with Cass Lake reporting an afternoon high of just -17°F. Wind Chill Values ranged from -35°F to -55°F around the state, making it extremely dangerous to be outside.

Snow, sleet, and freezing rain plagued the state over January 17-18 of 1996. Blizzard warnings were issued for southern, western and northern counties, as 10 to 20 inches of snow blew into huge drifts. Highway 14 between New Ulm and Sleepy Eye was closed for most of the day, and many schools were closed as well. More than 180,000 customers were without power in the Twin Cities area because of ice taking down power lines. That January brought over 30 inches of snow to many parts of the state.

Outlook:

Very cold air will dominate the weather for Saturday through Tuesday with little snow. Many areas will see subzero lows as well as subzero highs. Moderating temperatures closer to normal for this time of year will return for Wednesday through Friday of next week with a chance for snow by the weekend.