McEWEN, Tenn.—Tammy Shaw and her granddaughter, Hope Collier, were trying to find an escape path when water started spilling under their doors.
It was Aug. 21. A day Middle Tennessee residents won’t soon forget. Twenty people were killed. Nearby, nearly 21 inches of rain fell, shattering the state’s all-time record of 13.6 inches over 24 hours.
Collier, her car, and even her house were all swept away in the storm. Shaw and Collier both survived, but not without trauma.
“We were trapped in there, in that water,” Shaw said in the immediate aftermath of the storm.
“It didn’t even take 10 minutes and it was in my house, and then it wasn’t even 15 minutes and it was up to my ceiling,” Collier added.
The worst weather extremes that struck Tennessee and Kentucky in the past year were felt in neighboring Kentucky. Nashville was hit by major flooding in August, which caused extensive damage to homes and businesses and killed at least six people. In December, 80 people were killed in Kentucky by tornadoes. This is the highest death toll from a tornado outbreak in Kentucky’s history.
However, there are no more similarities.
As scientists increasingly trace the fingerprints of climate change on extreme weather and national weather experts recommend collecting a lot of localized, ground-level weather data in real time to save lives, Kentucky has built an extensive “mesonet,” while Tennessee leaves local forecasters partly flying blind in the storms.
The Kentucky Climate Center at Western Kentucky University in Bowling Green has, over the last 15 years, assembled a network of 76 local weather monitoring stations—the mesonet—and plans to add up to 20 more stations in the next three years.
“The weather service would be lost without the Kentucky Mesonet,” said John Gordon, meteorologist in charge of the National Weather Service office in Louisville.
Forecasters like Gordon use the stations to track rainfall, wind speed, temperature, sun and soil moisture to make their forecasts more accurate and to issue warnings.
Gordon stated that it is equally important to know when not to issue warnings. “You know, dear God, I don’t want to be the boy who cried wolf,” Gordon said.
Tennessee does not have a statewide network for localized weather monitors. Although the radar systems they use can be very useful, meteorologists claim, they can also miss what is happening below them. So in a state that’s 432 miles long, bordering North Carolina to the east and Arkansas and Missouri to the west, local forecasters are often left to estimate local weather conditions and storm activity where people are at risk.
“I’m sure we’ve missed quite a few high wind, high rain events across the state simply because we don’t have stations in those locations,” said Andrew Joyner, who leads a newly created Tennessee climate office and serves as the state’s official climatologist. One of his goals is to build a Tennessee mesonet with a station in each of the state’s 95 counties.
“It’s not cheap to build these stations and then to manage them,” he said. “But we feel like there’s a critical need for it.”
Billion-Dollar disasters on the rise
Scientists believe that greenhouse gases are being produced by fossil fuel emissions and other human activities, which are disrupting climate and weather.
Last summer, in the first installment of the Intergovernmental Panel on Climate Change’s Sixth Assessment Report, scientists found that global warming is worsening deadly weather extremes and that every part of the planet is affected. In the United States, the number of billion-dollar weather and climate disasters has been on the rise, even when adjusted for inflation—an annual average of 17 in the last five years, compared to an average of 7.4 per year since 1980. 20 billion-dollar weather and climate catastrophes were recorded in 2021. This includes storms, floods, and fires.
According to the most recent National Climate Assessment, cities in the Southeast are experiencing longer and more intense heat waves. Climate change is also accelerating the hydrologic cycle, worsening droughts as well as heavy rainfall.
“There is data suggesting that these storms that we are seeing are becoming more frequent and extreme,” said Leah Dundon, professor of civil and environmental engineering at Vanderbilt University and director of the Vanderbilt Climate Change Initiative.
According to the National Oceanic and Atmospheric Administration, Tennessee has had 33 major disaster declarations since 2000. These included flooding and severe storms.
There is also the Nashville two-day rainfall record in May 2010. In that time, 13.6 inches of rain fell in Nashville. This broke the 1979 record (6.7 inches) and caused devastating flooding that claimed 18 lives in Middle Tennessee. For last year’s nearly 21-inch storm in August, an area of up to 1,000 square miles experienced rainfall totals that would be expected to occur less than once every 1,000 years.
Joyner stated that the August storm was terrible, but it could have been worse.
“This was a largely rural area,” said Joyner. “It was devastating, it was awful, but it could have impacted a much higher population area. You could have moved it 60 miles east and it’d been right in Nashville, and what would that have caused? I mean this same event could really happen anywhere in Tennessee.”
‘A Fundamental Need’
According to the American Association of State Climatologists, 35 states have mesonets. These officials oversee the collection, analysis, and distribution of weather data and typically lead state climate offices. Mesonets may be funded with private or public money. A single monitoring station can cost up to $29,000, plus ongoing maintenance and operation costs.
In a way, mesonets are just another form of adaptation to a changing climate, said Kevin Brinson, director of the Delaware Environmental Monitoring System and chair of the climatologists association’s mesonet committee.
“I would argue that weather data drives so many decisions in our society and our economy,” Brinson said. “It’s a fundamental need.”
Rezaul Mahmood is the director of the High Plains Regional Climate Center (University of Nebraska-Lincoln).
“The idea is that if we have stations approximately every 20 miles, we should be able to observe weather properly, particularly like when you think of severe weather,” he said.
Most state mesonet systems don’t have weather stations every 20 miles, Mahmood said. However, mesonets still provide dozens more monitoring stations that what the National Weather Service does on its own, often at airports.
Mahmood explained that the first ones were in Nebraska and Dakotas in the 1980s. They had less frequent reporting and had no cell phone networks. Oklahoma was the next to develop one in 1990 with more frequent reporting.
He said that mesonets have been reporting their data approximately every five minutes over the years, thanks to better computer and communication technology.
Mahmood, who co-founded and developed the Kentucky Mesonet, said that networks are not only useful for forecasting.
He explained that farmers use the soil temperature and moisture data collected at stations to make decisions about planting and managing crops. He added that the National Transportation Safety Board had previously requested localized weather information to help investigate a multi-fatality motorcycle accident in Kentucky. Superintendents of schools use them to determine whether to declare a snowday, and students use them to learn more about the weather. He said that utilities track weather trends to plan for natural gas or electricity demand, and scientists use the data to conduct climate studies.
Brinson stated that while the early systems were primarily for agricultural purposes, many now play a significant role in public safety, out of necessity.
He said that the New York network was in large part a result of Superstorm Sandy, which caused a devastating storm surge to the New Jersey and New York coasts in 2012. It is the fourth most expensive U.S. hurricane ever recorded.
“A lot of times states kind of unfortunately have to go through some pretty rough times with weather sometimes before they start to see the value of having a real time network like that available,” Brinson said.
Tracking Tornadoes from the Ground
Although the science of climate change is still murky, there are signs that tornadoes are shifting from the Great Plains east to the Southeast in what some call Dixie Alley.
Gordon, in Louisville, said the Kentucky Mesonet was essential for tracking December’s unusual tornado outbreak and issuing warnings.
On the night of December 10, a series storms erupted in Arkansas, causing severe heat and humidity. They raced across Missouri and Illinois, Tennessee, Kentucky, and caused widespread destruction. They produced the nation’s deadliest December tornado outbreak, with at least 90 fatalities, 80 of them in Kentucky. One tornado cut a path across the ground for more that 165 miles and was nearly a mile wide when it ripped through western Kentucky.
“For the tornadoes, we were looking at … real strong pressure rises and falls very close to some of the stations,” Gordon recalled. “You could see some strong wind gusts.”
Forecasters use the mesonet once a tornado has struck the ground to determine if conditions are likely to support it, stop it, or elevate it. Before the Kentucky Mesonet meteorologists had to rely on weather radars, which help but don’t directly tell them what is happening on ground.
“The mesonet gives us ground truth,” Gordon said.
That’s also very helpful with rain and flooding, in part because they can tell meteorologists rainfall rates as the rain is falling. “Rainfall rates are everything,” he said. “It’s just literally gold for us.”
Warren County Farm
In 2007, the Kentucky Mesonet opened its first station on Western Kentucky University’s 800-acre farm in Warren County. On a recent winter afternoon, Stuart Foster, who created the state’s mesonet during his two-decade career as Kentucky’s state climatologist, explained how it worked.
This station has 17 sensors. It begins underground with soil probes to measure moisture and temperature. It then rises 10m to the top end of a tower.
Temperature, relative humidity, wind speed and wind speed are measured at different heights in order to identify temperature inversions that may influence fog formation or air pollution dispersion and help with daily weather forecasts.
The precipitation gauge looks abstract. It has a cylindrical base that is surrounded by metal teeth called wind baffles. These reduce wind flow and capture raindrops better. New cameras provide visual assistance for forecasters.
“We think of the mesonet here in Kentucky as a statewide infrastructure for environmental monitoring,” said Foster, a retired geography professor at Western Kentucky University.
The initial funding for the Kentucky Mesonet came from a federal grant of $3 million. In 2021, the Kentucky Mesonet received $750,000 from the state’s General Assembly, along with contributions from local sponsors and federal grants.
“It’s just a perfect example of how tax dollars should be spent and how programs should work, where we are very much integrated working towards a common purpose,” Foster said. “In this day and age, it’s kind of refreshing to find something like that.”
‘A Big Paradigm Shift’
Tennessee created a climate office in January 2021. However, it is still not funded. Joyner was named the state climatologist. Building a network is his biggest priority, and he has found support from academic and state institutions, as they look north to Kentucky’s success.
“Everybody’s drooling and jealous of the system they have in Kentucky,” Dundon, the researcher at Vanderbilt University, said.
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Joyner is working with state emergency management agencies, environment, agriculture, and weather agencies to determine how stations will be paid for, where they should be placed, and who will keep them maintained.
“Meteorologists love to get data and mesonets give data,” said Larry Vannozzi, the meteorologist in charge of the National Weather Service office in Nashville.
He stated that a Tennessee network would be a great help in tracking storms as they form and move through the state. “They fill in holes,” Vannozzi said, and “help us to understand what is happening now.”
Joyner said that he still needs to persuade administrators and politicians but is becoming more optimistic about a Tennessee mesonet.
“It would be a big paradigm shift,” Joyner said.
Caroline Eggers is the environment reporter for WPLN News Nashville.
Source: Inside Climate News