COLUMBIA — A light, cold drizzle fell as Jeanette Gieringer spoke about the long, hot summer.
Gieringer of Marshall runs a produce stand at the Columbia Farmers' Market on Saturday. This year, extreme heat and a lack of moisture reduced her usual harvest by one-third.
"Things that bloomed had trouble developing," she said. As a result, she couldn't bring any of her usual tomatoes and green beans to market this summer.
The National Drought Mitigation Center released the U.S. Drought Monitor, a weekly update of national drought conditions, which puts much of Missouri, including the northeast corner of Boone County, in moderate to severe drought conditions.
Precipitation for Columbia over the summer months was not far below average, but monthly maximum temperatures were well above average, according to the National Weather Service.
The continuously hot air allowed for a lot of evaporation, which led to the dry, drought-like conditions that farmers such as Gieringer experienced, said Anthony Lupo, MU professor of atmospheric science.
"A mistaken impression that people get about drought is that it's all about looking at how you're doing relative to normal precipitation," Lupo said, "when the real key is what your difference between precipitation and evaporation is."
Not only were maximum daily temperatures higher than usual, but minimum daily temperatures were abnormally high this summer, said Patrick Guinan, MU Extension assistant professor of climatology.
Beginning July 15, temperatures went 21 consecutive days without dropping below 70, even at night, setting a record in a city where weather records date back to 1890.
These continuously high minimum temperatures contributed to the heat stress many farmers saw in their crops this summer, Guinan said.
These hot, dry conditions are typical of La Nina weather conditions, Lupo said. Usually La Nina only lasts one year at a time, but this is the second year in a row that scientists have been observing La Nina weather patterns.
If they continue for a third year, we will see very similar weather conditions next summer, Lupo said. But three-year La Nina cycles have only occurred twice in recorded meteorological history.
Fortunately, the recent rainfalls in the Columbia area will help recharge the ground by increasing sub-soil moisture levels, Lupo said.
Gieringer said the September rains and cooler temperatures have helped bring up the production of her fall crops, which she hopes will help make up for some of her mid-summer losses.
She hopes people will continue to frequent the farmers' market and take advantage of this new, cool-weather harvest.