Cooler Days, Warmer Nights

Temperatures across the Midwest were cooler this week. Daytime maximum temperatures were 2-8°F below normal across the central and lower Midwest, with near normal or slightly above normal temperatures in the north (Figure 1). Minimum temperatures, however, were 1-10°F above normal for the entire Midwest, with the warmest departures in the east (Figure 2). As a result of the continued warm overnight temperatures, few locations across the lower Midwest had reached their first 32°F freeze of the fall by October 31 (Figure 3). Most locations in the northwest reached their first 28°F hard freeze of the fall this week (Figure 4), which was several weeks behind the historical median first hard freeze date (Figure 5). The first hard freeze was absent across the rest of the Midwest.

Soggy Weather

Much of the Midwest, except for the northern Great Lakes region, had very wet conditions. From Iowa and Missouri eastward to Ohio, precipitation totals ranged from 2-5 inches (Figure 6). A large portion of Iowa and small portions of Illinois and Indiana measured 500-750 percent of normal precipitation for the week (Figure 7). Northern Wisconsin, northern Michigan, and extreme northeast Minnesota had the driest conditions this week, with precipitation less than 0.5 inch.

Flooding Rainfall On October 25

A storm system that affected the southwest portion of the region on October 24 continued to intensify, bringing 2-4 inches of rainfall from Iowa to southern Michigan and northwest Ohio on October 25 (Figure 8). Heavy rainfall resulted in numerous streams in Illinois, Indiana, and southern Michigan, to be near flood stage or in minor flood stage according to the US Geological Survey (Figure 9).

Drought Update

Ample rain this week led to a slight contraction of drought in Iowa and Illinois, and a reduction in abnormal dryness across Missouri (Figure 10). However, dryness and drought conditions were expanded in Wisconsin where rainfall this week was minimal. Northern Minnesota remained in long-term drought, with most streamflow gauges much below normal for this time of year (Figure 11).