May 2021
Monthly Overview - May 2021
Fairly Dry May
Drier conditions were widespread across the Midwest in May
(Figure 1). Regionwide precipitation was 3.27 inches which was 1.11 inches below normal. This represented only 75 percent of the normal amount (Figure 2). Only a few areas of the region received significantly more than the normal amount of rain in May, with the wettest areas in southwestern Missouri. Meanwhile, northern Minnesota and most of the U.P. of Michigan received less than half the normal amount. Minnesota received only 44 percent of normal, which was among the 15 driest May’s on record (1895-2021). While scattered showers and thunderstorms led to some heavy rainfall amounts, very few of these storms were strong. This was evidenced by a lack of severe weather in the region.
Slightly Cooler
Temperatures were generally cooler in the Midwest for May
(Figure 3). Regional temperature was 58.7°F which was 1.0°F below normal. While the southern two-thirds of the region were slightly below normal for May, temperatures were mostly near normal in the Upper Midwest. Extremes on the warm and cold side were observed, however. Extreme warmth was recorded from May 18-24 in the Upper Midwest as a strong high-pressure system brought warm, moist air from the Gulf of Mexico northward. This led to the majority of the more than 500 daily high temperature records (Figure 4). However, extreme cold was observed during the last week of May
(Figure 5). Near-record late spring freezes were observed in northeastern Iowa and southern Wisconsin (Figure 6). Cold from the first two weeks also contributed to more than 700 daily low temperature records across the region
(Figure 7).
Drought Severity Increases
Lack of rainfall, increased water demand and drying soils all contributed to worsening drought conditions in May. According to the June 1 U.S. Drought Monitor, more than 17 percent of the Midwest was in drought (Figure 8). While drought coverage in the region slightly decreased from the beginning of May, severe drought area more than doubled. Both the Milwaukee and northern Chicagoland area were in severe drought by the end of May as streamflow decreased and soil moisture dried out. According to USDA NASS, soil moisture in southeastern Wisconsin was 68 percent short to very short. Areas of southwestern Michigan were also in severe drought at the end of May, along with northwestern Iowa.
Very Little Severe Weather
Severe weather events were muted across the Midwest, with most of the month’s reports coming on five days. On May 3, strong storms spawned an EF-1 tornado near Tompkinsville, KY. Weak tornadoes were also reported in southern Illinois as well on May 3 and May 6. On May 19, several tornadoes were reported in southeastern Minnesota, while strong winds were reported on May 25 in northern Wisconsin and May 27 in southern Missouri and western Illinois. These were the only major events, leading to a total of more than 230 reports for May. This was only 40 percent of the total from 2020 and less than 20 percent of May 2019’s reports.
Planting Season Ahead of Schedule
Drier conditions allowed farmers to plant corn and soybeans faster than average according to the USDA NASS Weekly Crop Progress Reports. Corn and soybeans were more than 90 percent planted in the Upper Midwest for the week ending May 30. Soybeans in the southern half of the region were the only areas below 90 percent planted in the Midwest, where planting was near the five-year average. Topsoil moistures were closer to adequate in the southern half of the region, with concerns about short to medium term dryness in Iowa, Minnesota and Michigan, where drought is prevalent.
-BJP-