Midwest Overview - July, 2004

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Cool, Moist, and Occasionally Stormy During July

July 2004 was wetter and cooler than normal in the Midwest. Conditions were ideal over the entire Corn Belt for corn fertilization, although the soybeans were slowed somewhat in their progress by a lack of heat. A number of serious severe weather outbreaks occurred in the Midwest during July, with the Roanoke, IL, F-4 that destroyed the Parson Manufacturing plant with no loss of life being the most noteworthy. Towards the end of the month, more cool weather arrived for the start of August. July 2004 was the 19th wettest and 9th coldest in the Midwest since 1895.

Most of the Midwest received more than 3 inches of rain in July. A number of locations from western and southern Missouri to southern Indiana and central Kentucky received 6-8 inches of rain, and the border region between Iowa and Minnesota also received more than 6 inches (Figure 1). Missouri and Indiana both had their 13th wettest July on record. More than 150% of normal precipitation fell in these areas, and most of the rest of the Midwest was also above normal for the month (Figure 2). Only northeastern Minnesota, northeastern Wisconsin, and the northern portion of Lower Michigan received less than normal precipitation. Temperatures oscillated back and forth during the month due to the frequent passage of weather systems, but temperatures were well below normal in average. Much of Iowa and Missouri and parts of the Upper Peninsula of Michigan were 3-4°F below normal, while most of the Midwest was 1-3°F below normal (Figure 3). Missouri had its 9th coldest July on record, while Illinois and Iowa had their 10th coldest. The whole summer in the Midwest was colder and wetter than normal due to the presence of an upper level trough over the region, in conjunction with a strong blocking ridge over the northeastern Pacific (Figure 4, Climate Diagnostic Center).