Midwest Weekly Highlights - August 15-21, 2015

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Adequate Precipitation for Much of the Region

Precipitation across the Midwest region August 15th - 21st resulted in rainfall totals within one inch of normal across much of the region (Figure 1).  Some locations observed 1-2 inches above normal rainfall, while the heaviest rainfall was observed in northwest Iowa and southwest Minnesota.  In these regions, above normal rainfall of 3 inches or greater was observed.   Much of the region observed 100% of normal precipitation, with the largest rainfall deficits in far northwest Minnesota, northeast Ohio, and northeast and southeast Missouri (Figure 2).  
 

Cooler Temperatures

Average temperatures across the Midwest ranged from the lower to middle 60s F in the northwest across Minnesota, the northern half of Wisconsin, the Upper Peninsula of Michigan, and much of Iowa.  The rest of the region experienced average temperatures between 70°F and 75°F (Figure 3).  In regards to normal, these temperatures were on the cool side for Minnesota, Iowa, Missouri, southern Illinois and Indiana, and much of Kentucky (Figure 4). Temperatures were near normal across northwest Wisconsin, central Illinois and Indiana, and southern Ohio.  An average temperature of 70°F to 75°F was above normal across the remaining areas in the northeast part of the region.  A vast majority of the region experienced average daily maximum temperatures between 75°F and 85°F, and average daily minimum temperatures between 55°F and 65°F.  
 

Late-season Tornadoes

Severe weather events and reports were primarily concentrated in and around Illinois, with wind events reported in areas of central and southwest Missouri (Figure 5).  A vast majority of the severe weather occurred on August 18, 2015.  Three tornadoes were confirmed in southeast Wisconsin near Waukesha (EF-0), Big Bend (EF-1), and Lake Geneva (EF-1), and four tornadoes all ranked EF-0s were confirmed in the Chicago suburbs of Naperville and Downers Grove.  The remaining two tornadoes touched down in Livingston County, Illinois, near the towns of Cornell and Chenoa.
 

Drought Monitor Conditions

Short-term drought is still present across northeast Iowa and southwest Wisconsin (Figure 6).  Short-term drought conditions are also present in northeast Minnesota and along the lake shore of Lake Superior in northern Wisconsin and the Upper Peninsula of Michigan.  Northwest Michigan has a small, dry region with short-term drought as well.  The rest of the region remains drought-free thanks to near normal precipitation. 

-OBK-