Midwest Weekly Highlights - August 1-7, 2011

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Summer Heat

The first week of August saw a continuation of the warm conditions from that second half of July. Temperatures were above normal across the region (Figure 1). The warmest area was southwest Missouri, where temperatures were 10°F to 13°F above normal. With temperatures well into the triple digits (Figure 2), all-time maximum temperature records were set at five locations in Missouri from August 2nd to 4th with three of the locations at record levels multiple days. Most stations in Missouri reached at least 100°F during the week along with numerous stations in southeast Iowa and a handful of stations in western Illinois. For the week, more than 250 record high temperatures were recorded.
 

Heavy Rains in the Upper Midwest

Heavy rains, with totals of 3" to 5" (Figure 3), fell in the upper Midwest but many other locations remained dry. Rainfall totals were two to five times normal in Minnesota and Wisconsin (Figure 4). Southern Missouri also saw preciptitation totals around twice their normal amounts. From the Minnesota-Iowa border to central Illinois, rainfall was sparse with weekly totals less than a tenth of an inch, less than 25% of normal. Drought conditions continued to spread into the Midwest from the summer-long drought in the southern plains (Figure 5).

Missouri River Flooding Eases in Western Iowa

Missouri River levels slowly receeded in western Iowa. The slow drop left the region in a vulnerable position if future rains fall in the region.
 

Flash Flooding Hits Minnesota and Wisconsin

Heavy rains brought downpours to northeast Minnesota and northwest Wisconsin on August 1st. Rainfall totals of 2" to 4" were common (Figure 6). Flash flooding closed state highways on both sides of the border as water on the roadways made travel unsafe.
 

Severe Weather Widespread

Severe weather in the first week of August consisted of mostly storng thunderstorm winds. All nine states reported damaging winds (Figure 7). The lone tornado report came on Aug 7th from Tawas City, Michigan (Iosco County) where a tornado damaged six homes and downed numerous trees. Scattered reports of hail over 1" came on several days with the largest hail, 2.75", reported on the 1st in Upper Sandusky, Ohio (Wyandot County).
 

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