June 2015
Midwest Monthly Summary - June 2015
Normal to Cooler June Temperatures
June average temperatures across the Midwest region ranged from the upper 50s F in the Upper Peninsula of Michigan and Arrowhead of Minnesota, warming consistently into the lower and mid-70s F into southern Iowa, much of Illinois, Indiana, Ohio, and eastern Kentucky (Figure 1). Western Kentucky, far southern Indiana, Illinois, and portions of southern Missouri had average temperatures in the mid to upper 70s F. In regards to normal, June average temperatures were cooler than normal in the Upper Peninsula of Michigan by 3 – 4°F, with eastern Wisconsin 1–2°F below normal (Figure 2). Much of Michigan was also 1–2°F below normal. Elsewhere, temperatures were within 1 degree F of normal across much of the Midwest region, with above normal temperatures along and south of the Ohio River Valley and most of Missouri. These regions were 1–3°F warmer than normal for the month of June.
The cooler than normal and close to normal temperatures over the north-central portion of the region were dictated by cooler than normal average maximum temperatures (Figure 3). Warmer than normal average low temperatures across the southern half of the region and portions of Iowa and Minnesota moderated average temperatures for the month (Figure 4). Average low temperatures in the southern half of the region were 1–4°F above normal, with pockets of warmer average minimum temperatures 4–6°F above normal in Missouri and far eastern Kentucky. Missouri was the warmest state, ranking the 39th warmest on record with an average temperature of 74.3°F. The coldest state was Michigan with an average temperature of 62.4°F, ranking as Michigan’s 38th coldest June on record.
Prolific June Rainfall across Much of the Midwest
The heartland of the Midwest saw prolific amounts of precipitation during June 2015, ranking as the Midwest’s 6th wettest June on record (1895-2015). Total observed rainfall exceed 10 inches in areas of northeast Missouri, sections of southern Illinois and northeast-central Illinois, along with north-central Indiana and a small portion of northwest Ohio (Figure 5). Missouri, Illinois, Indiana, and Ohio were by far the wettest states for the month of June, receiving 100% to 207% of normal rainfall (Figure 6). All four observed more than 5 inches of rain, with the heart of the precipitation falling across Illinois and Indiana where much of each state observed more than 7.5 inches of precipitation. Many local station records for daily and monthly rainfall were broken in June across Missouri, Illinois, and Indiana with localized monthly reports of over 18 inches in Jasper County, Indiana, at Rensselaer 6.2 SE. Others were 16.05 inches in St. Louis, Missouri, at the St. Louis Science Center; 20.15 inches in Troy, Missouri; 14.51 inches in Danville, Illinois, at the sewage plant; and 16.64 inches in Lima, Ohio, at the waste water treatment plant (Figure 7). Areas of Iowa were also impacted by heavy rain events. A June 24th rainfall event dropped 7.3 inches of rain at Columbia, Iowa, with monthly totals in some portions of central and southeast Iowa reaching more than 13 inches.
As a departure from normal, a swath of rainfall 6–8 inches (with a few locations in Missouri of 8–10 inches) above normal, fell from just north of the Saint Louis area extending northeastward through central and north-central Illinois, then onward to the east across north-central Indiana and northwest Ohio (Figure 8). Illinois, Indiana, and Ohio experienced their wettest June on record. Illinois observed 9.3 inches of rain, beating the previous record of 8.27 inches set in 1902, Indiana observed 8.9 inches of rain, beating the previous record of 8.13 inches set in 1958, and Ohio observed 8.15 inches of rain, beating the previous record of 7.27 inches set in 1902. Missouri had its 10th wettest June on record, observing 7.3 inches of rain statewide. The driest states in June were Minnesota, only receiving 86% of its normal precipitation (3.68 inches– normal of 4.29 inches), followed by Wisconsin which received 103% of its normal precipitation (4.35 inches– normal of 4.21 inches).
Rainfall Relieves Drought, but Harms Crops with Excess Water
Heading into June, Minnesota, much of Wisconsin, Michigan, northern Indiana and Ohio, the eastern half of Kentucky, and portions of the immediate Ohio River Valley in Indiana and Ohio were classified as abnormally dry by the U.S. Drought Monitor with pockets of moderate drought still present across northern Minnesota, the Minneapolis area, and northeast central Wisconsin. The abundant rainfall across much of the region in June alleviated the drought conditions across much of the Midwest, with drought conditions nearly vanishing across the Midwest by June 30, 2015 (Figure 9). Too much rainfall, however, quickly changed what looked to be an ideal growing season into questionable one due to flooded fields. According to Ag Answers of Purdue University, estimates from models that use reported yields for the current year and prior years, corn and soybean crop loss reached $475 million dollars for Indiana due to ponding water in fields that starved plants of oxygen and leached away nitrogen. The spread of disease and stalk and root rot were also of concern. On June 8th, USDA NASS rated the corn crop to be promising only to issue three weeks later that the crop would be around the second worst in 10 years. Ohio, Missouri, and Illinois have also reported crop damage from excess water. With all the rainfall came increased cloudiness. It was reported this month to be the cloudiest June on record at Chicago Midway Airport; the airport only averaged 46% sunshine. This broke the old record of 48% sunshine in June of 1942.
Record Rainfall Leads to Flooding across the Region
The record breaking monthly rainfall in Illinois and Indiana with localized records across other states, such as Missouri, during June resulted in flooding across the region. The heaviest rainfall was observed along the Illinois River and the Kankakee River Valleys in Illinois, the Wabash River Valley in Indiana, and the Missouri River Valley in Missouri, where major flooding occurred. As each of these rivers flow into the Mississippi River, flood warnings were issued along the Mississippi River from roughly Quincy, Illinois south all the way to Louisiana. Many warnings were still present heading into July. The Illinois River was closed to vessel traffic in certain areas, and to all recreational traffic along much of the river on June 30th due to the high waters.
Active Month of Severe Weather
Severe weather events were frequent across the Midwest during June. June 8 – 11 was an active period that brought hail, wind damage, and tornadoes across the region. June 17th – 22nd was another active period as the remnants of Tropical Storm Bill and several systems initiated thunderstorms with tornadoes, wind, and hail. A derecho event initiating in the Dakotas on the evening of the 21st tracked into Iowa and southwestern Wisconsin early in the morning of the 22nd bring winds of 72-95 miles-per-hour resulting in wide-spread damage to trees, power lines, grain bins, homes, and fields. After the derecho on June 22nd, storms initiated later that evening that generated an EF-3 tornado which damaged Coal City, Illinois. A total of 12 tornadoes were confirmed from this event by NWS- Chicago Romeoville, 8 of which were EF-1 intensity.
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Portions of this report were provided by the National Weather Service Indianapolis, the Indiana State Climate Office, the Iowa Department of Agriculture and Land Steward Ship, the Missouri State Climate Office. Additional, detailed information is available in weekly Climate Watch summaries.
This article was last updated on Monday, July 6, 2015.