Midwest Weekly Highlights - May 15-21, 2016

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A Bit Chilly

A cold Arctic air mass kept temperatures well below normal across the Midwest (Figure 1).  Missouri and most of the Ohio River Valley was 9-12°F below normal.  The Great Lakes and southern Minnesota were a bit warmer at 3-6°F below normal, and northwest Minnesota was near normal.  While these areas were warmer, many in Minnesota (Figure 2), Wisconsin (Figure 3) and Iowa (Figure 4) received a late spring freeze that caused damage to gardens and early planted corn and soybeans.  Over 100 record minimum temperatures were recorded on the cold morning of May 15, with over 60 in Iowa and Wisconsin (Figure 5).  Freezing temperatures were observed again in many of the same areas on the morning of May 16 (Figure 6).  Minimum temperatures remained in the 30s and low 40s for the remainder of the period and led to departures of 5-10°F below normal (Figure 7).

Maximum temperatures across Missouri and the Ohio River Valley were 10-15°F below normal for the period (Figure 8).  In fact, the maximum temperatures for May 17 through the morning of May 18 (Figure 9) was near the 30-year average minimum temperature in these areas (Figure 10).  Missouri alone broke more than 80 daily low maximum temperature records on May 17 through May 18 and over 240 low maximum temperature records were broken across the region during the period.
 

Dry Except in Kentucky, Southern Missouri

Dry conditions were common across most of the Midwest, as less than an inch of precipitation fell across the northern two-thirds of the region (Figure 11).  Most of Michigan, Wisconsin, Minnesota and Illinois were 0.5-1.0 inches below normal (Figure 12).  Parts of Iowa were even drier and were more than an inch below normal.  Wetter conditions were observed in southern Missouri and Kentucky. These areas received 1-2 inches of precipitation during the period.  In most cases, this was one-and-a-half to two times the normal amount (Figure 13).  Lower temperatures across the region coupled with fewer storm systems moving through the region led to a quiet week of severe weather, and no storm reports were observed in the region (Figure 14).
 

Drought Eliminated from Missouri

Heavy rainfall in Missouri led to the elimination of the only drought in the Midwest in the latest Drought Monitor from the National Drought Mitigation Center (Figure 15).  Heavy rain in southern Missouri and Kentucky also led to the elimination of some abnormally dry conditions as well.  Abnormal dryness was covering only about 4.5 percent of the Midwest as of May 17.  While drought has caused little concern so far in 2016, some drought worry may be present for Minnesota during the summer months.  The Climate Prediction Center’s Seasonal Drought Outlook for summer 2016 favors drought development across northern Minnesota and extreme northwest Wisconsin (Figure 16).
 

-BJP-