Midwest Weekly Highlights - July 1-10, 2012

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Little Rain through the Central Midwest

Precipitation was seen across the northern and southern portions of the region while much of the central Midwest saw little to no rain (Figure 1). Parts of Iowa, southern Wisconsin, and southern Minnesota only received up to 0.05", while northeast Iowa did not receive any precipitation during the start of July. The greatest precipitation amounts were seen in northern Wisconsin and eastern Kentucky, where 2.5" to 3" of precipitation fell during the first 10 days of the month. Other areas with precipitation over 1.5" was northern Minnesota, eastern Ohio, western Kentucky, and central Missouri. Many areas in the Midwest continued to add to their precipitation deficit for the year. For areas of Iowa and western Wisconsin, July kicked off with 1.6" below their normal precipitation (Figure 2). Few precipitation records were set across the region with the majority occurring on July 3rd in Michigan and Wisconsin and July 9th in southern Illinois, Kentucky, and Missouri.

New Month, Same Record Heat

A new month brought little relief to the region in regards to temperature. The entire region saw above average temperatures with areas of Wisconsin, Michigan and Indiana experiencing mean temperatures 10°F to 12°F above normal (Figure 3). Daytime maximum temperatures were exceedingly warm, with average maximum temperatures reaching 95°F to 105°F across a large part of the southern Midwest (Figure 4). The exceedingly warm daytime temperatures across the region resulted in widespread departures of 10°F to 14°F above normal maximum temperatures (Figure 5).

More than 1900 daily record high temperatures were set across the region with daily counts topping 100 on each of the first eight days of the month. Records peaked on the fifth through the seventh with each day having over 300 record highs. Statewide counts of daily temperature records for the first 10 days of July ranged from 99 in Minnesota to 367 in Missouri. At least one station in each of the nine Midwest states set or tied an all-time high record temperature.

Drought Intensifying

The July 10th US Drought Monitor shows worsened drought conditions in the Midwest (Figure 6). All levels of drought expanded, leaving only about 36% of the region without any drought (D1, D2, D3, or D4). Even though the extremely dry area in the southern Midwest received at least an inch of precipitation during the start of the month, drought conditions still worsened in this region. Exceptional drought (D4) developed in western Kentucky and southern Illinois. The last time any part of the Midwest was classified as being in a D4 drought was the fall of 2007 (Figure 7).

Severe Weather

Severe weather was reported in all nine Midwest states and on every day but the last during the first 10 days of July (Figure 8). There were hundreds of high wind and large hail reports across the region, with the largest event occurring on July 1st (Figure 9). The event on July 1st included a wind gust of 90 mph in Winfield, Illinois (DuPage County) and hail measuring 2.75" in Frankfort, Ohio (Ross County).

-ACC and MW-