Temperatures Split North to South
A divide across the Midwest occurred during the week, with warmer temperatures to the north and cooler to the south
(Figure 1). Minnesota, Wisconsin and Michigan were all 1-4°F above normal, with some areas in western and northern Minnesota 5-6°F above normal. Meanwhile, temperatures moderated to the south, with most of Missouri, southern Illinois, southern Indiana and Kentucky 1-2°F below normal. Some areas in southern Missouri were 3°F below normal. High pressure over the region kept temperatures seasonable, but several weak storm systems in the Upper Midwest brought warmer temperatures northward.
Most of the Midwest was very dry during the week (Figure 2), with most of Missouri, southern Iowa and southern Lower Michigan receiving little to no precipitation. Only areas in Kentucky, Minnesota and the U.P. of Michigan had amounts over an inch. These areas were the only ones with above-normal precipitation for the week
(Figure 3). Most of this precipitation fell through the mornings of August 19 (Figure 4) and August 22
(Figure 5). The dry weather in southern Iowa and northern Missouri continued a dry month of August, where some areas have received less than a quarter of normal so far (Figure 6).
Crop Conditions Decline
Drought along with the impacts of the August 10 Midwest Derecho led to a decrease in corn condition across the Iowa and the Corn Belt
(Figure 7). In Iowa, Ohio and Michigan reported less than 55 percent of the corn crop in good to excellent condition as of the August 23 USDA NASS Crop Progress Report. In Iowa, this was a nine percent drop from the previous week, and an 11 percent drop in Michigan. Percent poor to very poor also increased to 21 percent in Iowa (Figure 8). Advanced metrics tracking corn condition indicated a sharp decline as drought increased in Iowa in July while the August 10 derecho further impacted stressed crops.
Drought Expands in Iowa
Areas in moderate and severe drought increased across Iowa in the August 18 U.S. Drought Monitor
(Figure 9). Areas in northeastern Iowa developed drought along with several counties in southeastern Minnesota. Severe drought also slightly expanded eastward in western Iowa. Overall, 45 percent of Iowa was in drought, with nearly 90 percent of the state either abnormally dry or in drought.