April 2018
Monthly Overview - April 2018
Very Cold Temperatures
Average temperatures in April 2018
(Figure 1) were the second coldest on record (1895 to present) for the Midwest, with only 1907 being colder. Statewide temperatures in Iowa, Minnesota, and Wisconsin were all more than 10°F below normal and the other Midwestern states were 5° to 9°F below normal. Iowa and Wisconsin set new statewide records for the month while Illinois, Michigan, Minnesota, and Missouri all ranked second coldest. Indiana ranked third, Kentucky seventh, and Ohio ninth coldest. Departures from normal (Figure 2) ranged from 12°F below normal near the Iowa-Minnesota border to 5°F below normal in parts of Kentucky and Ohio. Monthly temperature records
(Figure 3) fell at 373 stations spread across all nine Midwestern states, including 82 in Iowa and 79 in Wisconsin and more than 40 in each of Illinois, Michigan, Minnesota, and Missouri. More than 3150 daily record lows were set across the region during April compared to fewer than 100 daily record highs. Readings fell into the teens as far south as Kentucky, the single digits in Missouri, and below-zero as far south as Iowa and Illinois. All states except Michigan saw temperatures reach into the 80s, with a couple stations reaching the low 90s in Missouri. Lakes in Minnesota were very slow to thaw with ice-out dates running at near-record delays and some yet to thaw out in central and northern Minnesota. Delays were as much as a month behind normal in southern Minnesota.
Snowy
April snowfall was well above normal across most of the Midwest with more than half of the region receiving at least twice normal and in many locations several times normal (Figure 4). Totals were more than a foot above normal from northern Iowa and southern Minnesota eastward to northern Michigan (Figure 5). Snowfall totals exceeded 30 inches in parts of Iowa, Minnesota, Wisconsin, and Michigan (Figure 6). More than 900 daily snowfall records were spread across 20 days in April with at least a dozen in all states and more then 250 in Wisconsin alone. Green Bay, Wisconsin (Brown County) set a record for the snowiest April with 36.7 inches which also ranked as the 2nd snowiest month throughout the year (45.6 inches in December 2008) in records extending back to 1895. More than 50 Wisconsin stations along with 20 plus in each of Iowa, Minnesota, and Michigan, set April snowfall records (Figure 7). A handful in the other states, except Ohio, also set April snow records..
Precipitation totals for April were generally below normal in the west and above normal in the east (Figure 8). The largest departures were in northern Missouri and southern Iowa where totals were as much as 3 inches less than normal, less than 25% of normal
(Figure 9). Some small areas of Ohio, Michigan, and northeastern Wisconsin had 150% of normal precipitation for the month. Totals topping 6 inches were reported in south central Kentucky and southeastern Ohio while northwestern Minnesota had locations with less than 0.25 inches (Figure 10).
Limited Severe Weather
April was relatively quiet for severe convective weather with reports limited to just seven days and only two days, 3rd
(Figure 11) and 13th (Figure 12), with more than a handful of reports. For the month, reports totaled 330 as compared to more than 800 last April. Tornado reports came from five states (IL, IN, KY, MO, and OH) on the 3rd, Missouri on the 13th, and Ohio on the 15th. Large hail was reported on just five days and in every state except Michigan. Damaging wind reports came in on four days sparing only Wisconsin and Michigan.
Slow Start to Planting
The cold and snowy conditions in the Midwest delayed planting by about 2 weeks. Soil temperatures were slow to warm and field conditions were not favorable until later in the month. Planting late in the month did proceed rapidly as soils warmed and dried out.
Drought Limited
Moderate drought was limited to less than 5% of the region throughout the month
(Figure 13). Areas in drought expanded slightly from about 2% to 4% of the region while the areas noted as abnormally dry shrunk from about 10% to 5% of the region. Only Missouri, Iowa, and Minnesota had areas in moderate drought in April. Cool temperatures reduced evaporation, and plant demand for water, helping to offset the very dry conditions in the drought areas.
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The Minnesota State Climatology Office also contributed to this report.
The Missouri Climate Center also contributed to this report.