Winter Cold Sets In

The coldest weather of the season arrived across the Midwest this week. Average temperatures were as much as 20°F+ below normal in Missouri, with lower, but still significant, departures of 10-15°F through the Upper Midwest (Figure 1). Every state had an average statewide temperature that was anomalously below normal. In Indiana, it was 15.8°F below normal; in Kentucky, 16.2°F below normal; and in Missouri, the state with the most significant departure, the average temperature was 20.1°F below normal. While it was just as cold in the Upper Midwest, temperature departures were not as anomalous for this time of year like in southern reaches of the region. The average temperature in Wisconsin was 11.9°F below normal, and in Michigan it was 8.4°F below normal.

Minimum temperatures were also very below normal. Illinois, Indiana, Iowa, Kentucky, and Missouri observed average minimum temperatures that were 15-20°F below normal (Figure 2). In fact, average minimum temperatures for much of Missouri and Illinois were below 0°F (Figure 3), while Ohio and Kentucky were the only states where the average minimum temperature remained above 0°F statewide. Minimum temperatures remained below 0°F for many southern locations through January 16. However, in Iowa, Minnesota, Wisconsin, and Illinois, minimum temperatures were generally below 0°F for the entire period. In Kansas City, Missouri, the daily record was broken three days in a row, January 13-15, as temperatures dipped below -10°F all three days.

While it was cold each and every night, the temperatures did not rise very much each day, and maximum temperatures were quite noteworthy. In much of the region, maximum temperatures were 10-20°F below normal (Figure 4). January 13-15 was the longest stretch of sub-5°F maximum temperatures in Kansas City since 1989, and only the 5th time in over 100 years that that happened. In Joplin, Missouri, temperatures stayed below 10°F January 14-15, which was only the 5th time that happened in over 100 years of recordkeeping.

Precipitation Falls Off

After a brief period of some noteworthy precipitation, totals fell off during the third week of the month. As temperatures dropped, high pressure settled in, and the area remained not just cold but very dry. Much of Wisconsin and Minnesota received no precipitation at all, while most of the region saw 25-50 percent of normal precipitation, at best (Figure 5). In the areas where precipitation fell, it was generally meager, with areas west of the Mississippi River observing generally less than 0.15 inches of precipitation (Figure 6). In the east, where the highest totals were, it wasn’t much better. Southeastern Kentucky, which received the most precipitation, saw only 0.75-1 inch for the entire week (Figure 6).

When it came to precipitation type, due to freezing temperatures for most of the period and most of the region, much of the precipitation that did fall fell as snow. Kentucky saw over 400 percent of normal snowfall (Figure 7). In Kentucky, as much as 7-10 inches of snow fell across the eastern part of the state (Figure 8). On January 15, Jackson, Kentucky had 6.4 inches of snow, the largest single-day snowfall since 2014. Lake effect snow also brought totals of 8-12 inches across part of Michigan’s coastline. Elsewhere in the region, less than 4 inches of snow was recorded.

An extreme lake-effect snow event affected far southwest Michigan and northwest Indiana with snow rates of 2-3 inches per hour. This was the result of mesovortices that formed due to convergent winds over Lake Michigan. As much as 2-3 feet of snow was reported in northwest Indiana, and a 5-10 car pileup shutdown the Indiana Toll Road. A record single-day snowfall of 21.9 inches was reported in LaPorte, Indiana.

Drought Monitor

By January 16, drought coverage had been improved across the Midwest. From January 9-16, there were one-category improvements in Illinois, Indiana, Ohio, Kentucky, and parts of Missouri. As much as 16 percent of D1 conditions were removed. D2 conditions also improved, with coverage decreasing from 20 percent of the Midwest to 13 percent. The Upper Midwest remained largely unchanged. Through the end of the third week of the month, a lack of precipitation ultimately ended anymore drought improvements (Figure 9).