Midwest Weekly Highlights - September 1-9, 2012

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Welcome Rains in the Southern Midwest

Heavier than normal rains fell across the southern half of the region during the first nine days of September (Figure 1). The remnants of Hurricane Isaac moved into Missouri and then spread to the east on the first two days of the month (Figure 2) with rainfall totals of 6 to 8 inches in some locations in Missouri and Illinois. Then on the 7th, heavy rains fell again across the southern Midwest with the heaviest rains in central Indiana where several inches fell across a large swath of the state (Figure 3). Daily precipitation records fell by the hundreds with over 400 records set or tied over the first nine days of September. More than 150 records were recorded on the first two days and again on the 7th and 8th of the month. Rainfall totals for the period were twice normal across the southern half of the Midwest with totals of 400% to 600% of normal from the Bootheel of Missouri to central Illinois and Indiana (Figure 4). The upper Midwest saw far less rain with totals ranging from near normal down to less than a quarter inch in southwest Iowa and most of Minnesota (Figure 5).
 

Warmth Again

Following the story for most of 2012, temperatures were above normal across nearly all of the Midwest. A small pocket of below normal temperatures was recorded in extreme northern Minnesota but the rest of the region was above normal, up to 6°F above normal in eastern Ohio (Figure 6). Across the region, the count of 90°F days in 2012 was running well above normal and highs topping 90°F continued add to the total for many locations over the first week of September. Daily temperature records were mostly record warm minimum temperatures with few record lows in the period.
 

Drought Eases

The rains in the southern Midwest put a dent in the drought but longer term precipitation deficits still remain and the soils are not yet back to normal for this time of year (Figure 7). The improvements were shifts to less severe categories of drought rather than elimination of drought (Figure 8). Midwest drought saw significant drops in the two most severe categories, Exceptional Drought (7% to 1%) and Extreme Drought (33% to 14%), but the total area in drought remained fairly consistent (65% to 63%). Less than 12% of the region is neither in drought nor classified as Abnormally Dry.
 

Severe Weather

Severe weather affected all nine states in the first week of September (Figure 9). Weak tornadoes were associated with the remnants of Isaac on the 1st but damage was limited. Most of the week's reports came from the 4th, 5th, 6th, and 7th. Hail over 2.50" in diameter was reported on the 4th in Fillmore and Houston Counties in Minnesota and again on the 7th in Boone and Warren Counties in Missouri. Thunderstorm winds caused widespread damage. The highest measured winds topped 70 mph on the 4th in Iowa, Minnesota, and Wisconsin and again on the 7th in Missouri, Kentucky, and Indiana. Hundreds of reports of trees and power lines being blown down dominated the damage reports. Additionally barns, commercial building roofs, and communication towers took damage as well as some vehicles on the road being blown over or off the road. On the 4th, a teenager fell from his bike into a flooded creek and was sucked into a storm sewer in Parma, Ohio (Cuyahoga County). After about 30 minutes of searching, he was found 1500 feet away, rescued, and treated for minor injuries.
 

-MST-