East-West Split on Temperature Departures

The eastern Midwest observed above-normal temperatures this week, ranging from 1-4°F (Figure 1). Defiance County, Ohio recorded an average temperature of 67.7°F, which was 4.2°F above normal for the week. Their highest maximum temperature was 92°F, which occurred on May 31. The western Midwest experienced below-normal temperatures ranging from 1-7°F below normal. The largest below-normal temperature departures were recorded in Missouri and Iowa. Barry County, Missouri recorded an average temperature of 60.1°F, which was 7.3°F below normal. Similar trends were observed in both the maximum temperatures (Figure 2) and minimum temperatures (Figure 3) this week. There were 33 low minimum and 85 low maximum daily temperature records broken or tied (Figure 4).

Variable Rainfall across the Midwest

Variable rainfall occurred throughout the Midwest this week (Figure 5). The heaviest totals occurred in northern Minnesota, northwestern Missouri, southcentral Indiana, and Ohio. Isolated locations in Minnesota received up to 4 inches of rain this week. Beltrami County, Minnesota measured 4.27 inches of rainfall (single-day maximum on May 29 was 2.01 inches). Several locations in Minnesota received 175-300 percent of normal precipitation this week (Figure 6). The precipitation was highly variable, which attributed to pockets of 25-75 percent of normal precipitation across the Midwest. Southern Indiana into Ohio received 100-175 percent of normal precipitation. Heavy precipitation in the upper Midwest resulted in above-normal stream flow values (Figure 7). Also noted, there were below-normal stream flows in western Kentucky, northeastern Illinois, and northwestern Indiana.

Tornado Outbreak in Minnesota on May 30th

There were 28 tornado, 46 hail, and 241 wind preliminary storm reports this week. Tornado reports spanned four days with most reports occurring on May 30 (Figure 8). There were 14 confirmed tornadoes in Minnesota that day. Both the Twin Cities, Minnesota and the Grand Forks, North Dakota National Weather Service Offices provided summaries for each of the tornadoes. There were 4 EF-2 and 10 EF-1 tornadoes. Fortunately, there were no reported fatalities or injuries from these tornadoes. The largest hail report of 2 inches in diameter, occurred on May 29 in Carlton, Minnesota. On May 25, several locations in Indiana received wind storm reports in excess of 60 mph. Unfortunately, Boone County, Indiana had a fatality as a boom lift was toppled as a result of the winds. Most wind reports occurred on May 30 with an 80-mph gust recorded in Hubbard, Minnesota. There were several reports of downed power lines, trees, and damage to buildings.

Drought Update

The May 31 U.S. Drought Monitor (Figure 9) had minor improvements and introduction of the abnormally dry (D0) category in the Midwest. The Moderate (D1) and Severe (D2) Droughts in northwestern Iowa remained unchanged.