December 1-7, 2024

Temperature

High pressure settled it in the wake of multiple Thanksgiving Weekend cold fronts, which meant sunshine and cold temperatures to start December. Average temperatures for the southern parts of the region were over 10°F below normal for the week (Figure 1). In the Upper Midwest and areas west of the Mississippi River, anomalies were less noteworthy as the cold front was far removed by this point and temperatures were rebounding by December 2.

Minimum temperatures were quite below normal, particularly in Illinois, Indiana, Kentucky, and Ohio (Figure 2). While temperatures in the Upper Midwest were in the single digits, it was the southern extent of this cold that was noteworthy. Over 100 daily low temperature records were set, mostly in Indiana, Illinois, Ohio and Kentucky (Figure 3). In parts of Indiana, minimum temperatures averaged nearly 16°F below normal for the entire week. In Indianapolis, 6 out of the first 7 days of December observed minimum temperatures below 20°F, which has only happened twice before since records began in 1873— in 1886, and 1893. In Cincinnati, the minimum temperature was at or below 20°F for the first 7 days of the month, consecutively, for only the 2nd time since records began in 1871, with the previous occurrence in 1886.

Maximum temperatures were most below normal in the east, and near or slightly below normal from the Mississippi River westward (Figure 4). Parts of Kentucky, southern Illinois, southern Indiana, and southern Ohio averaged over 10°F below normal for the week. In Rockville, Indiana, a station with records dating back to 1893, maximum temperatures were at or below 25°F for 3 consecutive days, December 1-3, for only the third time in December’s first seven days since records began. Meanwhile, by the end of the week, temperatures had recovered west of the Mississippi River. Temperatures reached the 60s in much of Iowa and southern Minnesota, breaking daily records in multiple locations on December 7.

Precipitation/Drought

Precipitation was minimal for most of the week, as high pressure was largely in control, keeping the region cold and dry. The only places with near- or above-normal precipitation were the northern half of Michigan, including the UP, as well as Minnesota’s Arrowhead region (Figure 5). When precipitation did fall, it was mostly in the wintry form, with 1-2 inches in places like St. Louis and Evansville, and nearly 2 feet in parts of Michigan’s UP (Figure 6). In just the 24-hour period ending the morning of December 5, parts of the UP observed one foot of snow, and many areas downwind of the lakes continued to experience snowfall in lighter amounts through the end of the week.

As for drought, conditions have continued to improve, albeit slowly. As of December 3, extreme drought (D3) was finally removed from southeast Ohio after nearly 5 months, the longest streak of D3 conditions in Ohio since drought monitoring began in 2000. Some improvements were made in northern Wisconsin and Michigan’s UP as well. While overall changes were minimal, trends have been positive, and there is no longer D3 or D4 drought anywhere in the Midwest (Figure 7).