Midwest Weekly Highlights - May 1-7, 2012

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Warm Continues into May

May was off to a warm start with temperatures averaging 4°F to 14°F above normal for the week (Figure 1). The warmest temperatures were generally to the south, from southeast Missouri to southeast Ohio, while temperatures were closer to normal across the upper Midwest. . Over 750 daily high temperature records were set, with dozens on each day from the 2nd through the 7th (Figure 2). There were no record lows during the week.
 

Heavy Precipitation for Many Locations

Heavy rains, with totals two to six times normal, fell in many Midwest locations (Figure 3). Much of the northern and central Midwest received twice normal or more rain during the week. Some of the drought stricken areas (Figure 4) in Minnesota and Illinois were soaked with welcome rains that will help alleviate drought conditions. Daily totals of 2" to more than 4" were reported with weekly totals of 6" or 7" in a few Wisconsin locations. Dozens of daily precipitation records records were set each day during the week and several of the daily records also set new records for any day in May. Areas with less than normal precipitation included southeast Missouri, northwest Minnesota, and the eastern Upper Peninsula of Michigan.
 

Severe Weather Widespread

Severe weather was reported across the region with reports coming on all seven days to start the month (Figure 5). The highest concentration of severe weather reports extended from Iowa and southern Minnesota to southern Ohio but all nine states reported wind damage and large hail with tornadoes in seven states. There were no tornado deaths reported. Tornadoes were reported on the 1st in Minnesota, Iowa, Illinois, Indiana, Ohio, and Kentucky with damages to trees and farm buildings. Tornadoes were also reported on the 3rd in Iowa, on the 4th in Iowa and Minnesota, and on the 6th in Illinois and Missouri. Hail stones measuring 2.50" to 2.75" in diameter were reported on the 1st in Kentucky and Iowa, on the 2nd in Minnesota, and on the 6th in Illinois and Missouri. Thunderstorm winds did damage somewhere in the Midwest each day with numerous reports of damage to trees, power lines and poles, and buildings. In Minnesota there were even reports of boats blown onto nearby roads.
 

Heavy Rains Lead to Flooding

The heavy downpours in many locations led to either flash flooding or river flooding. A woman was swept away by flood waters while evacuating her trapped car in Athens County, Ohio on the 4th. Flash flooding led to closed highways and swamped basements all across the region. Minor, and in a few cases moderate, river flooding occurred in every Midwest state except Kentucky but typically just for a day or two in any one location (Figure 6).
 

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