Monthly Overview - April 2021

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Fairly Dry

Drier weather was common across the Midwest during the month of April (Figure 1).  Total precipitation for the month was 2.70 inches, which was 0.63 inches below normal.  That amount was nearly 20 percent less than normal (Figure 2).  Dry conditions were worst in Iowa, with large portions in the central and northeastern parts of the state receiving less than a quarter of normal.  Statewide, precipitation ranked among the 15 driest on record (1895-2021).  Some wetter weather was observed, however, in the northern Great Lakes, with most of northern Minnesota and the U.P. of Michigan receiving above normal amounts.  Moderately wet conditions were also found across most of Missouri and west-central Illinois.
 

Extreme Temperatures Average Out

Back and forth temperatures throughout April averaged out to near normal across the Midwest (Figure 3).  Regionwide temperature was 49.0°F which was 0.3°F above normal.  Temperatures whipsawed from extremely above normal from April 4-9 (Figure 4) to extremely below normal from April 17-23 (Figure 5).  These extremes led to hundreds of daily records across the region, with more than 750 low temperature records (Figure 6) and more than 850 high temperature records (Figure 7).
 

Rare Late April Snowstorm

A rare snowfall event for late April impacted the southern Midwest from April 19-21 (Figure 8).  Exceptionally cold temperatures near to below freezing allowed light to moderate snow to fall across Missouri, Illinois, Indiana, Ohio and northern Kentucky.  Amounts from 1-3 inches were measured in northern Missouri, while lake-enhanced amounts in northern Indiana and northwestern Ohio were 2-5 inches.  This event was the only major snowstorm of the month (Figure 9), with snowfall amounts in the U.P. of Michigan similar to northwestern Ohio.  Most of Iowa, Wisconsin, southern Minnesota and Lower Michigan had less than an inch of snow for the month.
 

Drought Expands in the Upper Midwest

Drier than normal conditions led to an expansion of drought in the Upper Midwest during April (Figure 10).  Areas in drought increased approximately eight percent from 11 to 19 percent from the beginning (Figure 11) to the end of April.  Most of this expansion occurred in Michigan, where more than three quarters of the state was in moderate drought as of the April 27 U.S. Drought Monitor (Figure 12).  Drought was also introduced in southern Wisconsin as soils dried out and water demand began to increase as planting season neared.
 

Quiet Month of Severe Weather

Severe weather was minimal across the Midwest in April.  A total of more than 130 reports of strong winds and hail were reported along with several weak tornadoes.  Many of these reports came from hail on April 5 in the Minneapolis/St. Paul, MN area (Figure 13), wind in Missouri on April 7 (Figure 14) and scattered severe weather in southern Missouri on April 9 (Figure 15) and April 28 (Figure 16).  National Weather Service surveys confirmed several tornadoes in southern Missouri on April 28 as well.  The minimal severe weather was less than 15 percent the number of reports in April of 2020.
 

-BJP-