May weather full of extremes

COLUMBIA, Mo. – May’s weather was one for the record books.

“There is great disparity between what we saw last year vs. this year,” said Pat Guinan, state climatologist with the University of Missouri Extension Commercial Agriculture Program.

The temperatures in March through May made it the coolest spring since 1984, Guinan said. By contrast, temperatures in the spring of 2012 were the highest on record. There was an 11-degree average difference between the two years, “nothing short of incredible,” he said.

Not only was it cool. It was wet.

It was the 17th-wettest May recorded since 1895, according to the National Weather Service’s Cooperative Weather Station Network in Missouri. The state recorded an average of 7 inches of precipitation in May, making it the wettest May since 2002.

Several inches of snow fell across parts of the state on May 3. Significant May snowfall was recorded only two other times in Missouri: 1907 and 1929.  “What some folks witnessed was something they hadn’t seen in a lifetime,” Guinan said.

“A historic snowstorm in the first week of May bookended by a damaging tornado in the St. Louis area at the end of May was an incredible dichotomy of what Mother Nature had to offer for the month,” he said.

May’s numerous precipitation events exacerbated flooding along rivers and streams across the state, he said. The drought is over and, unlike last year, concerns have shifted to excessive water and flooding.

Using May climatology for Missouri as a predictor, Guinan said this summer has an enhanced likelihood of being near- to below-normal in temperature and near- to above-normal in precipitation. “We had our 17th-wettest May on record this year, and history indicates that unusually wet Mays tend to be followed by cooler to near-normal summers as well as wetter to near-normal ones for Missouri,” he said.

But, he cautions, Mother Nature may yet hold some surprises. “There have also been numerous occasions, both in temperature and precipitation, when we abruptly transitioned from one extreme to another in a short period of time.”