Midwest Overview - April 2013

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April Showers

April precipitation was significant across much of the Midwest, with a large portion of the central Midwest receiving at least 6" of precipitation throughout the month (Figure 1). In fact, portions of Iowa, Illinois, Indiana, and Michigan received monthly precipitation of 6" to 8". This precipitation was 150% to 300% of normal across much of the region (Figure 2). The high precipitation totals in the central Midwest mainly resulted from an event on April 17th and 18th, when a strong low-pressure system brought heavy precipitation and damaging flash floods to portions of Iowa, Missouri, Illinois, Indiana, and Michigan. A significant number of April precipitation records fell during this event, in addition to an event on April 10th and 11th (Figure 3). The abundant April rainfall has led to several stream gauges across the region that are at or above their flood stage in early May (Figure 4).

Every Midwest state, with the exception of Kentucky and Ohio, ranked in their states' top 12 wettest Aprils on record. According to the Iowa state climatologist, a statewide average of 6.63" during April broke the previous monthly record set in 1999 of 6.25". This is the ninth consecutive wetter than normal April for Iowa. Based on preliminary data, with a statewide average of 5.75", Michigan also broke their monthly precipitation record for April, which was previously set in 1929 with 5.70".

Lingering Snowfall Season

April was not only a rainy month for much of the region, but a snowy month as well for northern states. Over 20" of snow fell in portions of Minnesota, northern Wisconsin, and Upper Michigan throughout the month (Figure 5). The most significant monthly snowfall totals were in Duluth, Minnesota (St. Louis County), where 50.8" were reported at the Duluth International Airport. The snowfall in Duluth topped the previous April record by nearly 20", but it also was Duluth's snowiest month ever for any month of the year.

The significant April snowfall totals were anywhere from 20" to 35" above normal for this time of year (Figure 6). Over 475 daily snowfall records were set throughout the month. Just over two dozen of these records were also monthly records, as well as two that either tied or broke the all-time record for snowfall. The all-time snowfall records of 15" (tie) and 13.5", occurred in Elk River, Minnesota (Sherburne County) and Isle, Minnesota (Mille Lacs County), respectively, on April 19th.

Chilly April for Midwest

With the exception of Ohio, Kentucky, and portions of Iowa, April was unseasonably cool for the Midwest (Figure 7). The largest departures of 9°F to 14°F below normal were found in Minnesota (Figure 8), where a statewide average April temperature of 34.3°F ranks 4th coldest among all Aprils. Iowa and Wisconsin also ranked in their states' top 10 coldest Aprils on record. Several daily temperature records were set throughout the month, a majority of which were record lows (Figure 9). There were a few record highs set, many of which fell on the 9th and 10th.

Slow Start to Midwest Growing Season

Typically, April is the month when farmers in the Midwest get out in the fields to plant this season's corn crop. Unfortunately, the wet conditions and lingering snow in the north have delayed planting in the region. As of April 28th, only 16% of the corn crop was planted that is usually planted by this time of year. The table below summarizes the percent of corn planted by state (and the Midwest region) as of April 28, 2013 compared to the 2008-2012 normal.

In addition, the growing season is also off to a slower start for portions of the region. Due to the colder temperatures, the western Midwest is anywhere from 30 to 150 days behind normal growing degree days by this time of year (Figure 10).

CORN	Percent Planted (as of 4/28/13)	Departure from 2008-2012 Average
Illinois	1%	-35%
Indiana	1%	-29%
Iowa	2%	-34%
Kentucky	24%	-24%
Michigan	0%	-17%
Minnesota	0%	-33%
Missouri	15%	-27%
Ohio	2%	-23%
Wisconsin	0%	-12%
MIDWEST	5%	-26%

Drought Improvement

The area in the Midwest impacted by drought reduced by nearly 20% during the month of April, a welcome result of the significant rainfall since drought has been dominant in the region since last summer (Figure 11). A small portion (0.04%) remains in extreme drought (D3), while almost 20% remains in severe drought (D2) and 33% in moderate drought (D1). Only one-quarter of the region is classified on the US Drought Monitor as abnormally dry or in drought. The last time so little of the region was classified as abnormally dry or in drought on the US Drought Monitor was late July 2011.

Wet and Cool Spring Season So Far

So far, the 2013 spring season has been unseasonably cool and wet. Average temperatures are running anywhere from 1°F to 13°F below normal (Figure 12) and precipitation is 100% to 200% of normal across much of the region (Figure 13). However, the latest Climate Prediction Center 3-month outlook for May, June, and July shows that the pattern may change in terms of temperature (Figure 14). A majority of the Midwest, with the exception of Minnesota, Wisconsin, and Upper Michigan, have a greater chance of above normal temperatures during the next 3 months. Precipitation is less predictable, however, with equal chances of above, below, or near normal precipitation across the region.

-MW-
The Indiana State Climate Office also contributed to this report.
The Iowa Climatology Bureau also contributed to this report.
The Kentucky Climate Center also contributed to this report.
The Minnesota State Climatology Office also contributed to this report.
The Missouri Climate Center also contributed to this report.