Excessively Warm December Continues for Most in the Midwest

Above normal temperatures continued through the fourth week of December for much of the Midwest, except for northern Minnesota. Widespread average temperatures ranged from 4-17°F above normal (Figure 1). Isolated locations in southern Missouri, southern Illinois, and southern Kentucky recorded over 17°F above normal. Butler County, Missouri checked in with an average temperature of 54.1°F, which was 18.1°F above normal. Similar trends were observed in maximum temperatures where large portions of the Midwest were 5-19°F above normal (Figure 2). Average minimum temperatures displayed a similar pattern, but not as excessive as the average maximum temperature (Figure 3). There was a total of 239 daily high maximum temperature and 140 daily high minimum temperature records broken or tied this week (Figure 4). As for Minnesota, widespread below normal temperatures of 1-9°F and isolated locations in excess of 9°F below normal were observed. Kittson County, located in northwestern Minnesota, recorded an average temperature of –1.4°F, which was 9.2°F below normal for the week. One record low daily maximum temperature was recorded in central Minnesota this week (Figure 5).

Variable Midwestern Precipitation

Combined with warmer temperatures, variable precipitation was observed throughout the Midwest. Northern Minnesota experienced two weeks in a row of above normal precipitation, where many locations were 0.5-1.5” above normal for the week. Along an axis stretching from central Missouri to eastern Ohio, precipitation ranged from 1.5-2” above normal (Figure 6). Many locations along this axis received 1-2.75” of precipitation (Figure 7). Logan County, located in western Ohio, received 2.75” of precipitation, which was 1.88” above normal. There were 59 daily precipitation records broken or tied this week, mostly extending from central Missouri to eastern Ohio, but some additional locations in Minnesota and Wisconsin were reported (Figure 8). South and east of this axis received isolated precipitation totaling less than 1.5” of precipitation, which left many of these locations 0.5-1” below normal for the week.

Continued Snowfall in the North

Most of the precipitation that fell in the upper Midwest was snowfall. Widespread snowfall recorded in north central Minnesota, Wisconsin, and Michigan’s Upper Peninsula ranged from 5-15" with some locations receiving over 22” of snow (Figure 9). Locations in central Minnesota recorded snowfall that was 300-750% of normal (Figure 10). Crow Wing County, Minnesota, measured 22.6” of snow, which was 19” above normal for the week. To the east, many locations in Wisconsin and Michigan’s Upper Peninsula saw 100-300% of normal snowfall. Central to eastern Michigan received widespread 5-10" of snow, which ranged 125-300% of normal snowfall for the week. Forty-seven daily snowfall records were broken or tied in Minnesota, Wisconsin, Michigan, northern Illinois, and northern Indiana (Figure 11). There were observations of snowfall extending southward through Iowa, central Illinois, central Indiana, and central Ohio. South of this line, all of the precipitation fell as rain.

Slight Changes to the Drought Monitor including Regional Improvements

A few changes were noted in the December 28, 2021 Drought Monitor (Figure 12). There was expansion of the D0 (abnormally dry) region in Missouri and expansion of D1 (moderate drought) in southeastern Wisconsin. The D2 (severe drought) region in central Wisconsin was also expanded slightly to the east and west. Slight improvement in Minnesota was observed where portions of the D1 (moderate drought) were downgraded to D0 (abnormally dry). Additionally, improvement can be noted in northwestern Wisconsin where D1 (moderate drought) was improved to D0 (abnormally dry). D1-D4 (moderate, severe, extreme, and exceptional droughts) percent land area saw a 1.04% improvement this week.