Midwest Weekly Highlights - July 25-31, 2010

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Slightly Warmer Than Normal

The last week of July was slightly warmer than normal. Temperatures ranged from near normal in parts of Minnesota and Ohio to about 5°F above normal near the confluence of the Ohio and Mississippi Rivers (Figure 1). Daily temperature records set during the week were almost all record high minimums. In fact, most of the warmth was attributable to warmer minimum temperatures (Figure 2) as maximum temperatures were near normal across the region (Figure 3).
 

Variable Precipitation Amounts

Precipitation varied across the Midwest in the last week of July. In Lower Michigan and along the Ohio River, many places received no rain during the week (Figure 4). But above normal rains fell in many locations. Above normal rains extended from most of Iowa, across the Illinois-Wisconsin border, through southern Michigan and northern Indiana and Ohio. Northern Missouri and west central Illinois also got above normal rains as did smaller pockets of Kentucky and the upper Midwest. Drier than normal conditions occurred along the Ohio River, southern Missouri, southwest Iowa, the arrowhead of Minnesota, and much of Lower Michigan (Figure 5). More than 150 daily precipitation records were set during the week with multiple records in each state. Drought continued in the upper Midwest and southeast Missouri (Figure 6).
 

Flooding

River flooding was an issue across Iowa, northern Missouri, northern Illinois, and southern Wisconsin (Figure 7). These areas have seen flooding for a number of weeks as river levels rose with the rains and eased between rains.

Up to 3" of rain fell in eastern Missouri on the night of the 26th. Mobile homes were evacuated in Bannister City (St. Francois County) and in nearby Park Hills, many residences were completely surrounded by the rising waters. Water quickly receded after the rains ended.

Berea, Kentucky (Madison County) was hit with flash flooding on the evening of the 27th. Rescues were needed to help the occupants of two vehicles to safety. Water backed up into the school through floor drains and damaged much of the technology center. Some homes took on water in their basements as well.
 

Severe Weather

The last week of July had a couple days with most of the week's severe weather. The upper Midwest took the brunt of the damage on the 27th (Figure 8). Five tornadoes were reported in northern Wisconsin (Polk, Barron, Ashland, and Iron Counties). The tornado in Iron County was the first confirmed tornado since 1970 and the two twisters in Ashland County were the first since 1998. A teen was struck by lightning in Duluth, Minnesota (St. Louis County) that same day. Large hail was reported in Minnesota (St. Louis County) and Wisconsin (Shawano, Bayfield, Ashland, and Sawyer Counties). Trees and power lines were blown down across the upper Midwest.

The severe weather shifted to the southeast on the 28th (Figure 9). Most of the reports were of trees and power lines blown down by thunderstorm winds with some falling on houses or blocking roads. There was also a single report of 1" hail in Port Clinton, Ohio (Ottowa County).
 

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