2019 continued wetter trend for Lincoln, state

2019 continued wetter trend for Lincoln, state

Lincoln wasn't exactly the poster child for global warming in 2019.

The average temperature for the year was about 51 degrees, more than half a degree lower than the average for the past 30 years, and the second year in a row with lower-than-average temperatures.

The city went without a triple-digit temperature for the first time in more than two decades.

And we saw nearly 40 inches of snow from January-March, part of a 2018-2019 winter that was the second-snowiest on record.

That doesn't mean the signs of the effects of climate change weren't there, however, especially if you look back over the past few years.

"Studies show us that climate change is real and it's already here," State Climatologist Martha Shulski said. "The trend for Nebraska will be for more extremes."

Chief among climate change effects locally is more moisture in the atmosphere, which leads to more heavy rain (or snow) events, Shulski said.

"There is actually a century-long trend toward increasing wetness for much of the north-central U.S.," Shulski said. "In Nebraska, annual precipitation totals have increased over time, by about 10% in the last hundred years. The rate of change is amplified over the past three decades."

For Lincoln, the past few years have been some of the wettest in recorded history. The official precipitation for 2019 was 36.11 inches, marking the third year in a row the city has topped 35 inches — the average is just less than 29 inches. There has never been a three-year stretch in records that go back to 1887 with that much rain.

Over the past five years, Lincoln topped 35 inches four times, and the nearly 179 inches from 2015-2019 are the most for any five-year period in those same 132 years of record-keeping. Five of the 25 wettest years in Lincoln history have occurred since 2014.

Lincoln also had 124 days with measurable precipitation in 2019, the most since 1993 and the third-most ever.

The Capital City was not alone in seeing increased precipitation. The National Weather Service's Hastings office said 2019 was the wettest year ever for St. Paul, which had more than 45 inches of rain, and Ravenna. It was the second-wettest year ever for Kearney and third-wettest for Grand Island, with both cities seeing nearly 40 inches of rain.

The state as a whole saw its third-wettest January-October period and its fourth-wettest January-November period.

All of that rain caused well-documented flooding last year, from the March flooding that hit much of the state and caused more than $1 billion in damage, to the more localized flooding that hit the Kearney area in July and Grand Island in August.

Gov. Pete Ricketts pointed out in a tweet Wednesday that there was some kind of flood warning, watch or advisory in the state for 318 days in 2019.

The large amounts of rain have had another effect.

Shulski said the rise in moisture in the atmosphere is "thought to be a main driver" of a recent trend of fewer very-high summer temperatures in some portions of the central U.S., including Nebraska.

However, that doesn't necessarily mean summers are cooler.

"One thing we are seeing is warmer nights, also driven by more moisture in the atmosphere," Shulski said. "When the dew point temperature is higher, that also elevates the nighttime summer lows."

Shulski said the high atmospheric moisture content, along with cloud cover, led to below-average daytime highs. But it also led to higher nighttime lows. 

In July, for example, the average high was 0.3 degrees below normal, but the average low was 1.8 degrees higher. In August, the monthly high was 2.7 degrees below where it should be, but the average low was 1.5 degrees above. In September, Lincoln set an all-time record for the month for minimum temperature at 62.4 degrees, which was 9.1 degrees above average.

Even with the lower daytime summer highs, the increased moisture may make it feel hotter in coming years.

A report released in July by the Union of Concerned Scientists predicts that by 2100, the number of days the heat index tops 100 degrees in Lincoln and eastern Nebraska could hit 26 or more, up from less than 10 now.

While the summer temperatures seem to be the ones most affected by the increased moisture, long-term studies actually show precipitation patterns are changing, with less rain in the summer and more precipitation in winter and spring.

Shulski said models indicate that by mid-century, there will be about 15% more precipitation in spring and winter months and 10% less in summer months.

A Columbia University study released last month predicts a similar pattern not just for Nebraska, but for all of the Corn Belt.

The study, done by atmospheric scientist Mingfang Ting, found that summer storms in the Corn Belt are weakening and producing less rain, which is leading to evaporation exceeding rainfall.

Ting attributed the phenomenon to the rising temperatures in polar regions, which reduces the temperature contrast with mid-latitude regions and leads to lower storm intensities.

“Our results suggest that in the future, the U.S. Midwest Corn Belt will experience more hydrological stress,” Ting said in a news release.

Looking to the more immediate future, forecasts don't shed a lot of light.

Both the one- and three-month outlooks from the National Weather Service give the whole state an equal chance of seeing above- or below-normal temperatures. The one-month forecast calls for an equal chance of above- or below-average precipitation as well, while the three-month forecast shows a slight chance for above-average moisture for most of the state.

One of the big concerns is the potential for a repeat of serious flooding this spring.

In November, Shulski and her colleagues on the Nebraska Climate Assessment Response Committee warned that high river levels, combined with high amounts of moisture in the soil in much of the upper Midwest, make for favorable conditions for flooding.

The Weather Service also has warned that widespread ice jams are likely to occur this spring, even on rivers that don't normally experience them.

Photos, video from March flooding in Nebraska

Reach the writer at 402-473-2647 or molberding@journalstar.com.

On Twitter @LincolnBizBuzz.

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