Temperature

Temperatures were above normal by 2-4°F for much of the region (Figure 1). Some areas across the southern Great Lakes and Kentucky observed average temperatures up to 6°F above normal. Meanwhile, across Minnesota, temperatures were near to slightly below normal.

Minimum temperatures were 4-6°F above normal for much of the region (Figure 2). Some pockets of northern Indiana, the Greater Chicago area, southern Illinois, and southern Missouri observed minimum temperatures as much as 6-8°F above normal. Across Michigan’s Upper Peninsula (UP) and Minnesota, minimum temperatures averaged near to slightly below normal.

Maximum temperatures were 3-6°F above normal along the I-80 corridor and also through much of Kentucky (Figure 3). Across parts of Michigan, they were as much as 6-9°F above normal. Maximum temperatures averaged near to slightly above normal elsewhere, save Minnesota, where temperatures ran up to 6-9°F below normal in parts of the state.

Precipitation/Drought

Precipitation was scattered about the region, with above-normal totals across parts of Illinois, Indiana, Iowa, Missouri, Ohio, and northern Lower Michigan (Figure 4). Other areas, like southern Missouri, central Michigan, and the Kentucky Coalfields, observed precipitation that was less than 50 percent of normal. Continued heavy precipitation over southern Indiana kept the White River elevated at minor flood stage at several gauges.

Drought conditions remained largely unchanged from May 12 to May 19. There were slight increases across all categories, though most of the drought expansion occurred over Kentucky (Figure 5).

Storm Reports

There were over 700 storm reports this week, with 547 wind reports and 143 hail reports (Figure 6). There were also specifically 40 tornado reports, most of which occurred over Iowa and Missouri with a multi-day severe weather event. 18 tornadoes occurred across northern Iowa on May 17 alone, including 11 EF1 tornadoes. On May 18, the storm pushed eastward, with wind gusts exceeding 80 mph reported across Michigan. In Detroit, a gas station canopy was blown down by strong storms.