Midwest Weekly Highlights - July 25-31, 2004

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July Ends in a Very Cool Way

The tendency towards wet and cool weather continued to the end of the month, but with limited severe weather this week. Precipitation amounts exceeding 3 inches were common in eastern Missouri (Figure 1), including in the city of St. Louis. The central latitudes of the Midwest and northern lower Michigan missed out on most of the rain this week, with less than 50% of normal precipitation for the week (Figure 2). Temperatures were up to 10°F below normal in Missouri, while most of the Midwest was 4-7°F below normal (Figure 3). The huge rain event in Missouri eliminated the abnormally dry area previously established in southeastern Missouri, although dryness expanded in northeastern Wisconsin (Figure 4, National Drought Mitigation Center).

Heavy Rain Event in Missouri

On July 29 and 30, a strong cluster of thunderstorms slowly moved through Missouri from south-central to east-central portions of the state. By the morning of the 30th, heavy precipitation was still falling as the morning rush hour started (Figure 5, NWS). The combination led to many traffic accidents and flooded roads. The radar precipitation totals show the path of the heaviest rain very clearly (Figure 6, NWS).