July 8-14, 2002: Stormy in the Northern Midwest, But Drought Expands.

During July 8-14, an upper level trough brought several weather systems on a path from north to south across the region. Minnesota was especially hard hit, with storms dropping 6-10 inches at some locations on July 9-10 and causing renewed flooding in the previously saturated region. Several other areas also received significant precipitation, including greater than two inch totals in Iowa, Missouri, northern Wisconsin, and Kentucky (Figure 11). These areas mentioned above received more than 150% of normal precipitation for the week (Figure 12), while much of the eastern Midwest received less than 50% of normal. Due to the upper level trough and the influx of Canadian air into the region, temperatures were a few degrees below normal in most of the Midwest, especially at its central latitudes (Figure 13). Therefore, some of the areas that have not received rain in a while benefitted from reduced evapotranspirative loss during this period.

The U.S. Drought Monitor for July 9 indicated the arrival of moderate drought in northern Iowa (Figure 14, NDMC). The last 30 days have been exceedingly dry in the southern two-thirds of the Midwest. Much of Illinois, Ohio, southwestern Iowa and northwestern Missouri have received less than 50% of normal precipitation from June 15 to July 14 (Figure 15). The MRCC soil moisture model indicated that an even larger area is suffering from topsoil moisture shortages (Figure 16). As the Corn Belt begins to enter the critical fertilization period, there is great concern about the lack of rain and its affect on corn silking, especially in Nebraska and Iowa. However, due to the hit and miss nature of the precipitation over the past month, there are also rapidly drying areas in the central and eastern Corn Belt. For instance, in east-central Illinois at the location of the MRCC, only 0.07 inches of rain have fallen since June 15, more than 4 inches below normal for the period. Lawns that are not irrigated are rapidly becoming dormant.