Widespread Above-Normal Temperatures

This week, temperatures were well above normal throughout the whole Midwest, except for a small area in Michigan’s Upper Peninsula. Average temperatures reached 14°F above normal in northern Minnesota, and dipped to 2°F below normal in the UP (Figure 1). Statewide, Minnesota had the largest deviation of 9.8°F above normal and Michigan had the smallest deviation of 3.9°F above normal. The largest temperature departure this week was seen in Cooper County, Missouri where the mean temperature was 49.2°F (13.9°F above normal). Maximum temperatures were also above normal everywhere in the region besides Michigan, where temperatures were near or slightly below average (Figure 2). Minnesota saw average maximum temperatures up to 10°F above normal and northern Michigan saw temperatures up to 4°F below normal. Minimum temperatures this week were well above normal, with temperatures in northern Minnesota reaching upwards of 20°F above normal (Figure 3). Average minimum temperatures in a small portion of Michigan’s Upper Peninsula reached 2°F below normal. This week, at least one station in each state, except Michigan, recorded mean temperatures within the top 10 warmest on record for the second week in December (Figure 4).

Western Midwest Above-Normal Precipitation

Compared to last week, the western Midwest saw a large increase in the amount of recorded precipitation. The western part of the Midwest received up to 750 percent of normal precipitation in some areas, while the eastern Midwest received less than 100 percent of normal precipitation (Figure 5). Each state in the region had locations that recorded at least 0.5 inches of precipitation, and areas of Missouri received over 4 inches of precipitation (Figure 6). Parts of Indiana, Michigan, Wisconsin, and Ohio saw less than 0.2 inches of precipitation. Missouri’s Ripley County recorded 4.96 inches of precipitation, making that the highest total in the Midwest this week. Multiple stations in Minnesota, Illinois, and Iowa set records for the wettest second week of December on record, while some rankings in Michigan were the driest second week in December on record (Figure 7). Streamflows this week stayed consistent with last week’s, with conditions slightly improving in Illinois, Missouri, and Kentucky (Figure 8).

Northern Snowfall

The snow stayed in the upper Midwest this week. Northwestern Minnesota saw up to 500% of normal snowfall totals and northwestern Iowa saw up to 300 percent of normal totals. A sharp cutoff between the above normal and below normal snowfall totals occurred in central Iowa and extended eastward. Much of Wisconsin and Michigan saw less than 75 percent of normal snowfall (Figure 9). Most locations in the upper Midwest received at least 1 inch of snow and totals exceeded 4 inches in most of Minnesota (Figure 10). Lake County, Minnesota recorded 17.2 inches of snow, making that the highest recorded total this week. There were 20 daily snowfall records broken or tied this week, and they all occurred in Minnesota, Iowa, and Wisconsin (Figure 11).

Drought Monitor Update

Drought conditions in the Midwest improved slightly compared to last week as land classified in drought decreased by over 4 percent (Figure 12). One-category improvements were seen largely in Kentucky, southern Ohio, and southwestern Missouri. One-class degradations occurred in Michigan this week.