Midwest Weekly Highlights - July 25-31, 2012

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Precipitation Totals Varied in the Midwest

Precipitation during the last week of July was varied across the Midwest (Figure 1). There were parts of the Midwest with abundant precipitation, while other parts of the region lacked precipitation. Over an inch of precipitation fell in parts of Minnesota, Wisconsin, Iowa, Michigan, northern Indiana, Ohio, Kentucky, and southeast Missouri. Almost the entire of state of Michigan received at least an inch of precipitation and some parts of the state received 3" to 5" of rainfall during the week, bringing some relief to a state with moderate to severe drought. As a result, there were several daily precipitation records set throughout the week.

On the other hand, some parts of the Midwest were left fairly dry. And unfortunately, many of the regions that were left dry coincide with the parts of the Midwest experiencing the most intense drought (Figure 2). Central Illinois, western Indiana, southwest Missouri, and parts of southern Minnesota and western Wisconsin only received 0.01" to 0.2" of precipitation, and part of central Illinois did not report any precipitation during the week.

As a result of the varied rainfall, some parts of the Midwest experienced above normal precipitation for the week, while others experienced below normal precipitation (Figure 3). Central Illinois and southwest Missouri received anywhere from 0% to 25% of their normal precipitation. Where the rainfall was abundant in the Midwest, precipitation was 150% to 750% above normal.
 

Above Average Temperatures

The week started out with hot temperatures for much of the region, but temperatures cooled off a little bit as the week progressed. However, much of Missouri had temperatures remain hot throughout the week, with average maximum temperatures ranging from 95°F to 105°F across a majority of the state (Figure 4). Overall, average daily temperatures were above average across the region, except for northern Minnesota and northern Michigan, where temperatures were near- to below-normal (Figure 5). The highest departures of 8°F to 10°F were in southwest Missouri.

Consistent with much of July, average maximum temperatures were significantly above average for parts of the region (Figure 6). Maximum temperatures were at least 8°F above average in southern Illinois and Indiana, western Iowa, and much of Missouri. In southwest Missouri, maximum temperatures were 9°F to 13°F above average. Minimum temperatures also ran above average for most of the region, but they were not quite as extreme as maximum temperature (Figure 7). High maximum and minimum temperatures resulted in a few hundred daily temperature records being set throughout the week, with the majority occurring at the beginning of the week (Figure 8).
 

Drought

The July 31st US Drought Monitor shows continued drought for the Midwest (Figure 9). Although there was slight improvement in the northern and eastern regions, expansion of extreme drought to cover most of Missouri meant that more than 30% of the region was in extreme or exceptional drought. All nine Midwest state had extreme drought. Ohio and Minnesota were well under 1% but Missouri had more than 90% of the state in the extreme drought category. Over 70% of the region as a whole was classified in drought.
 

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