April 15-21, 2024

Temperatures

Average temperatures were above normal to the south and east, near normal across Iowa, southern Minnesota, and Wisconsin, and slightly below normal over northwestern Minnesota. In Kentucky, average temperatures were as much as 8°F above normal (Figure 1). Elsewhere across the Ohio and mid-Mississippi River Valleys, average temperatures were 3-6°F above normal.

Average minimum temperatures for the week were as much as 10°F above normal in south central Kentucky, and as little as 1-2°F above normal in Minnesota and Iowa (Figure 2). They were generally 3-6°F above normal for most spots along and north of I-70. Bowling Green, Kentucky had a low temperature of 67°F from April 15-16, making it only the third time since records began in 1897 that the temperature did not drop below 67°F on consecutive days in April. There were 46 daily record low temperatures set during the week, all within Illinois, Iowa, Minnesota and Wisconsin (Figure 3).

Average maximum temperatures were 2-4°F above normal across the Ohio River Basin, near normal across most of Michigan, Iowa, and central Wisconsin, and below normal across northwestern Wisconsin and Minnesota (Figure 4). Terre Haute, Indiana reported a temperature of 87°F on April 15, which was only the 10th time the temperature rose that high in April since 1875, and the first time since 1952. From April 14-17, Louisville, Kentucky observed 4 consecutive days of temperatures at or above 85°F for only the 8th time in April since 1872. In total, there were over 150 daily record high temperatures set during the week (Figure 5).

Precipitation

There was an abundance of precipitation across the western Midwest, with many places west of the Mississippi River observing over 150 percent of normal precipitation (Figure 6). Minnesota, central and western Iowa, and northwestern Wisconsin observed 1-2 inches of precipitation, which is more than the 0.5-1 inch of rain most of those areas observed during the entire first two weeks of the month. A lack of precipitation was most notable in eastern Kentucky and southern Ohio, as well as much of central and southwestern Missouri, where precipitation was as little as 0-10 percent of normal. Much of Indiana, Ohio, and Kentucky saw over 4+ inches of rain during the first two weeks of the month (Figure 7), as opposed to the 0.5-1 inch much of these areas saw during this past week (Figure 8). As of April 21, Youngstown, Ohio was having its wettest April on record in 94 years with a total of 5.60 inches of rain, 2.94 inches above normal. Zanesville, Ohio was also reporting the wettest April on record thus far with 5.64 inches of rain.

The precipitation across the western Midwest provided drought relief. By April 16, some D3 removal was noted across eastern Iowa, where some areas have been in extreme drought since July 2023. Since heavy rains at the beginning of the period were not considered until the following week, even more drought removal came between April 16 and the end of the week. D0 dropped from 51 percent to 41 percent of the region with major removal of dry conditions in Minnesota and Wisconsin, while D1 dropped from 25 to 23 percent of the region (Figure 9).

Severe Weather

It was an active week with 34 tornado reports, 134 hail reports and nearly 300 wind reports (Figure 10). In Grundy County, Missouri, an anchored car port was blown away on April 16. An EF1 tornado with winds of 95 mph was confirmed over Smithville Lake in Missouri, just north of Kansas City. Another EF1 tornado with winds of 90 mph was on the ground for 0.5 miles and caused 1 injury near Hopkins, Missouri.

By April 17, the same system moved east and produced more storms over mostly Ohio and southeastern Michigan. Two EF-1 tornadoes that occurred on April 17 were confirmed by the National Weather Service in Cleveland, with both tornadoes producing winds of 110 mph. Straight line winds were just as notable, with a 66 mph wind gust reported by an ASOS station in Cleveland.

On April 18, another outbreak occurred in and around the St. Louis, Missouri area. Hail larger than golf balls was reported near Cypress, Illinois. In St. Louis, straight line winds were strong enough to rotate a traffic signal 90 degrees. In Belleville, Illinois, a tree limb flew into a family’s bedroom just minutes after they had left.