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Record precipitation experienced by central region of the United States in May

by Wyoming Livestock Roundup

The month of May proved to be full of moisture throughout the central region of the United States, and the first half of June was similar. Nationwide, May 2015 was the wettest month on record.

“Out of 1,445 months, May 2015 goes on top,” stated University of Missouri Extension and State Climatologist Patrick Guinan in an online, monthly climate update from the National Oceanic and Atmospheric Administration (NOAA) on June 18.

National average precipitation for May was about 4.33 inches, almost 1.5 inches above normal.

“The wet patterning is continuing,” added Guinan. “Some significant rainfall is anticipated over the next couple of weeks.”

If the trend continues, this year’s May-June moisture could rank in the top five on record, which currently defines 1908, 1915, 1957, 1995 and 2010 as years with the most precipitation in May and June since recordkeeping began 121 years ago.

Stream flow

“Accordingly, the rivers and streams over the middle part of the country have responded to all of this wetness,” Guinan noted.

Record stream flow has been measured in Texas, Illinois, Indiana, Michigan, Ohio, Missouri and Colorado.

“Southwestern South Dakota experienced their highest June 18 stream flow on record,” he added.

In southeast Wyoming, the Platte River showed near-flood stages on the day of the outlook and minor flood conditions were visible along other areas of the Platte flowing through Nebraska.

“As we go eastward into Illinois, many parts of the Illinois River are witnessing moderate flood conditions,” Guinan continued.

Flood records in the last month were noted on the Powder River in Wyoming, the Cheyenne River in South Dakota, the Salt Creek in Nebraska and the Little Blue River in Kansas.

“It’s interesting to note that prior to all of this moisture, there was a concern about the navigation season across the Mississippi and Missouri rivers,” Guinan added of drought challenges before May.

If rains continue, high river levels could cause different concerns.

“High river levels could impact the navigation season,” he explained.

Rivers in the Ohio Basin were at or above flood levels on June 18.

Condition changes

“As the remnants of Tropical Storm Bill move into the Ohio River Basin, there could be some response to the forecasted rainfall as well,” Guinan added, referring to stream flow levels in the area.

Recent rains have greatly improved the season’s drought outlook.

“All the way from Minnesota down to Texas there were some significant swaths of abnormally dry to severe drought conditions. Fast forward and less than a month later it looks like someone took their eraser out and took away quite a bit of those antecedent conditions,” he explained.

Impacts from recent weather across the central region have included an effect on various crops in the United States.

“Prior to all of these rains, there were some very cold winter temperatures, and we also had agricultural impacts on winter wheat, sugarbeets and canola with damage due to a late May freeze,” Guinan commented.

Winter wheat and soybeans

In some areas, winter wheat experienced stress from dry conditions and minimal snowpack.

“In the Dakotas, this led to freeze injury,” he said.

Alternately, in Michigan and Indiana, drier weather may be an advantage for winter wheat producers in those areas.

“Wet conditions that emerged in May might actually create more opportunity in parts of Kansas for diseases, and the wheat can become vulnerable,” he noted.

The National Agriculture Statistics Service indicated that nearly 70 percent of winter wheat in Michigan and Indiana was considered to be in good or excellent condition on the day of the outlook webinar.

“In Missouri and parts of Kansas, a big impact of the moisture has been delayed soybean planting,” continued Guinan.

Missouri, the furthest behind in soybean planting, had only 42 percent of the crop planted by June 18.

“We have 3 million acres yet to be planted in Missouri, and unfortunately, the existing wet conditions do not help at all,” he stated.

In Kansas, almost a third of the soybean crop was reported to be in very poor to poor condition, likely due to low snowpack followed by heavy precipitation.

“That also extends to Nebraska and South Dakota,” he continued.


Moving on to corn condition, Guinan presented a positive outlook.

“The corn crop is looking pretty good across the north central region. It will be interesting to see how the numbers respond with these big rain events that are forecasted here in the next couple of weeks,” he stated.

Guinan noted that in some areas, impacts from the excessive moisture include a greater opportunity for plant diseases, as well as stress to trees, fruit crops, row crops, forages and turf due to extended periods of cloudiness.

“In some areas, there have also been nutrient deficiencies due to nitrogen leaching and a lot of flooded corn and yellow corn issues,” he explained.


Outdoor recreation activities have also been compromised with recent weather.

Guinan continued, “Since Memorial Day when pools and golf courses were opening, there hasn’t been much activity because of these extended cloudy, rainy periods,” he explained.


In contrast, lawn care businesses have been doing well this season with lawns growing exceptionally well.

“Another good aspect across the middle part of the country is pasture and rangeland,” Guinan said. “As of June 7, 63 percent of the country on average was seeing very good condition for pasture.”

Going into the next couple of weeks, conditions across the country will be affected by the aftermath of Tropical Storm Bill as well as the impacts from El Niño.

“El Niño is here to stay,” Guinan stated. “There is a strong probability, a 90 percent chance, that El Niño will continue through the end of 2015.”

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at

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