Midwest Weekly Highlights - April 17-23, 2021

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Significantly Colder

Temperatures were well below normal across the Midwest during the week (Figure 1).  The cooler air that began to invade the western half of the region in the previous week persisted and advanced during the week, with most of the Ohio River Valley 4-8°F below normal, while most of southern Iowa, Missouri and southwestern Illinois were more than 9°F below normal.  The extreme cold was most pronounced on April 20 (Figure 2), April 21 (Figure 3) and April 22 (Figure 4), where most of the region had minimum temperatures below freezing.  Some areas in the U.P. of Michigan had minimum temperatures below 10°F on April 21.  An exceptional more than 500 low temperature records were broken across the region from the cold (Figure 5), with the majority occurring from April 20-22.
 

Rare Late April Snow in the Southern Midwest

Exceptional cold coupled with a storm system brought a rare snowfall event for late April to portions of the southern Midwest (Figure 6).  Snowfall began through the morning of April 20 (Figure 7) in northwestern Missouri before continuing through the morning April 21 into Indiana and Ohio (Figure 8).  Light snow showers lingered through the morning of April 22 as well (Figure 9).  Some areas in northwestern Missouri had 1-3 inches of snow, with areas from central Indiana eastward towards Lake Erie receiving 2-5 inches.  Most of Illinois had less than an inch.  More than 150 daily snowfall records were broken from this snowfall event (Figure 10).
 

Very Dry

Despite snowfall in the southern half of the region, precipitation amounts for the week were well below normal (Figure 11).  No areas had more than 0.75 inches for the period, with most of the Upper Midwest receiving less than a quarter of an inch.  Only a few isolated areas in northern Minnesota and the U.P. of Michigan had more than 50 percent of normal for the week (Figure 12).
 

Drought Significantly Expands in Michigan

Widespread expansion of moderate drought occurred in Michigan according to the April 20 U.S. Drought Monitor (Figure 13).  An increase of 40 percent across the state was observed to 57 percent of the state.  Most of Lower Michigan was either in moderate drought or abnormally dry.  Meanwhile, drought remained in northwestern Iowa and northwestern Minnesota, with long-term severe drought still affecting these areas.  Moderate drought also expanded to the northern half of the Chicago Metro area.  Overall, 11 percent of the Midwest was in drought, with nearly 17 million people living in drought affected areas.
 

-BJP-