December 15-21, 2023

Another Week, Another Temperature Torch

The average temperature was well above normal for most states during the third week in December. Much of Minnesota was almost 15°F above normal for the week (Figure 1). Even in Kentucky, where temperature departures were less noteworthy, the average temperature was generally 3°F above normal.

Much of the Upper Midwest observed minimum temperatures that averaged over 10°F above normal, with roughly 5-10°F deviations everywhere outside Kentucky and southern Ohio (Figure 2). In St. Cloud, Minnesota, a minimum temperature of 37°F on December 15 was 27°F above normal, and tied the previous record low, which was just two years prior in 2021. On the same day, record low temperatures were recorded in Park Rapids, Minnesota; Milan, Minnesota; Sault Ste Marie, Michigan; and Alpena, Michigan. All of the aforementioned stations have over 100 years of observations on record. By December 16, temperature anomalies continued moving south and east, with record minimum temperatures set in Waterloo Iowa; Moline, Illinois; Rockford, Illinois; and Cedar Rapids, Iowa. Minimum temperatures were in the upper 30s to low 40s, which was generally 20-25°F above normal for the date. A brief cool down brought minimum temperatures back to near normal mid-week, before more warmth just before the holiday weekend. Kansas City, Missouri had a record warm minimum temperature of 51°F on December 21, which was almost 30°F above normal.

Maximum temperatures were 5-10°F above normal across the region (Figure 3). Parts of western Minnesota observed average maximum temperatures generally 12°F+ above normal. The period started off warm, with Hancock, Michigan, on Michigan’s Keweenaw Peninsula, recording a maximum temperature of 49°F on December 15. That was 21°F above normal, and the warmest on record for that location. On December 17, a maximum temperature of 43°F was the warmest on record for that date in Sault Ste. Marie in 136 years of recordkeeping. Alpena tied the previous record for December 17 with a maximum temperature of 47°F. Like minimum temperatures, maximum temperatures cooled mid-week before starting to rise again by December 21.

Precipitation Returns

Precipitation was not very plentiful for the first three weeks of December, with most of the region having received less than 50 percent of normal precipitation (Figure 4). Only parts of Missouri, Illinois, and central Minnesota received near or above normal December precipitation thus far. This figure includes snow, which was running its own deficit through December 21. Most of the region has received less than 30 percent of normal snowfall, if any (Figure 5). Most of the precipitation that did occur during the past week was light, with amounts generally a half-inch or less for most of the Midwest, with isolated pockets of closer to an inch in western Indiana, eastern Illinois, areas in and around Lake Superior, and parts of Ohio (Figure 6).

Much of the precipitation this period fell as part of a lake-effect snow event that brought 2-4 inches of snow to Cleveland proper. Neighboring towns reported 6-8 inches of snow. The same event also caused lake-effect snow showers across Michigan’s Upper Peninsula (UP), where isolated spots picked up over 4 inches.

Drought Continues

Drought persisted into the third week of December. Expansions were noted in D1 (moderate drought), D2 (severe drought), and even slightly in D3 (severe drought). The D3 conditions across Iowa expanded to include some areas surrounding Des Moines proper (Figure 7). D1 expanded across much of Indiana and northwestern Ohio. Little expansion was noted across most of the rest of the region, but there were no major improvements either.