Midwest Overview - August 2012

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Precipitation Returned to Some Dry Portions of Midwest

The month of August finally brought near normal to slightly above normal precipitation to some of the areas in the Midwest that were significantly deprived of precipitation in June and July. A band of precipitation measuring at least 3" stretched from southwest Missouri to eastern Michigan and northern Ohio, with some areas within this band receiving up to 6" throughout the month (Figure 1). Despite the 3" to 5" in some portions of Missouri, the north-central part of the state received much less, only 0.5" to 1.5" throughout the month. Other areas with less precipitation include Minnesota, northern Wisconsin, Upper Michigan, southeast Missouri, northern Kentucky, and parts of southern Ohio.

August precipitation ranged from below normal to above normal in various parts of the Midwest (Figure 2). The area in north central Missouri that received much less precipitation than the rest of the state received only 10% to 25% of their normal August precipitation. On the other hand, portions of Illinois, Indiana, Ohio, Michigan, and Kentucky received 125% to 150% of their normal August precipitation, with small portions of central Illinois and central Indiana receiving 150% to 175% of normal. Overall, throughout August there were almost 500 daily precipitation records set, a handful of monthly precipitation records, and a few all-time precipitation records as well.
 

Near-Normal Temperatures Across the Region

For many locations across the Midwest, August broke a string of warmer than normal months that have been trending since last fall. Overall, average temperatures were close to normal across a majority of the region (Figure 3). Some smaller portions of the region experienced temperatures that were 1°F to 2°F below normal, while small portions of the northern Midwest experienced temperatures that were 1°F to 2°F above normal.

The near normal average temperatures results from the fact that on average, maximum temperatures trended a few degrees above normal across much of the region (Figure 4), while minimum temperatures were a few degrees below normal (Figure 5). Overall, there were just over 1,000 daily temperature records set throughout August (Figure 6) and a handful of monthly temperature records.
 

Despite Rain, Drought Persists

Despite precipitation in some drought-stricken areas of the Midwest during August, the US Drought Monitor did not indicate that there was much improvement in drought conditions across the region throughout the month (Figure 7). At the end of August, just over 65% of the region remained in some level of drought, compared to the 71% at the end of July. The highest level of drought, exceptional (D4), increased by just over 2% throughout the month of August. In order to see improvement in the coming months on the US Drought Monitor, the region will need to continually experice near to above normal precipitation throughout the fall. As August was coming to a close, the remnants of Hurricane Isaac were making their way to the Midwest. As a result of the significant precipitation this system brought to the southern Midwest, there was finally some improvement in drought conditions on the September 4th US Drought Monitor (which will be discussed in next week's report).

Unfortunately, much of the rain that the region received in August came too late to save the drought-stressed crops in the region. Overall, the corn condition as of September 2nd remains poor throughout a majority of the Midwest states (Figure 8). Missouri and Kentucky reported the largest portion of poor or very poor corn, while a majority of the corn in Minnesota remains in fair or better condition.

Summer 2012 Wrap-Up

The end of August also marked the end of the meteorological summer. Overall, summer temperatures were slightly above normal and precipitation was near to below normal across much of the Midwest. Average temperatures were 1°F to 4°F above normal across much of the region, with eastern Kentucky experiencing near normal summer temperatures (Figure 9). The summer started out very warm, with June and especially July having temperatures that were unseasonably warm. However, August brought some cooler temperatures to the region, somewhat reducing the overall summer temperature departure.

Summer precipitation ranged from only 3" in small portions of the Midwest to over 15" of precipitation in northern Minnesota (Figure 10). Overall, summer precipitation was below normal across much of the region, mainly in the western Midwest and through southern Indiana and Ohio (Figure 11). Northern Minnesota, northern Michigan, and portions of Kentucky were the only locations where summer precipitation was above normal (100% to 150%).

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The Indiana State Climate Office also contributed to this report.
The Kentucky Climate Center also contributed to this report.
The Missouri Climate Center also contributed to this report.
Purdue Extension also contributed to this report.