Warmer Temperatures Trickle In
Warmer weather began to move back into the Midwest during the period
(Figure 1). Parts of Minnesota, Wisconsin, Iowa and the U.P. of Michigan had above-normal temperatures for the first time since the third week of July. Most of Minnesota was 6-9°F above normal. Over 100 daily high maximum and minimum temperatures were broken in the Upper Midwest from the warm stretch (Figure 2). Meanwhile, cooler temperatures remained across Indiana, Ohio, Kentucky, eastern Illinois and southern Missouri. Kentucky was 5-7°F below normal while Indiana and Ohio were 2-5°F below normal. Maximum temperatures were a strong contributor in Kentucky, where highs were 7-10°F below normal
(Figure 3). Several dozen low maximum temperature records were broken as well (Figure 4).
Dry Weather Continues
Very dry conditions continued across most of the Midwest
(Figure 5). Little to no precipitation fell in Wisconsin, Michigan, Illinois, Missouri and eastern Iowa. Most of Indiana, Ohio, western Iowa and southern Minnesota received less than a half inch. Kentucky and northern Minnesota were the only areas with near- or above-normal precipitation (Figure 6). The rainfall in northwestern Minnesota, which has been in drought throughout the summer, was more than twice the normal amount (Figure 7). Severe weather was limited to only a few hail reports in northern Minnesota and wind reports in Missouri (Figure 8).
Drought and Dryness Expanding
Drought expanded to nearly nine percent of the Midwest according to the September 12 U.S. Drought Monitor
(Figure 9). Most of this expansion occurred in northwestern Minnesota. Rainfall in these areas occurred after September 12, however. Severe and Extreme Drought expanded slightly in southern Iowa and and was added in several northwestern Minnesota counties. Meanwhile, abnormally dry conditions expanded to 37 percent of the region. Most of Illinois, eastern Missouri, southern and eastern Iowa and southern Lower Michigan were considered abnormally dry. The last time 37 percent or more of the Midwest was considered abnormally dry was November 10, 2015 (Figure 10).