Kentuckians can expect more extreme weather events, and forecasting them may get trickier

Record rainfall brought devastating floods to Eastern Kentucky July 25 to 30, but the bulk of that rainfall fell the night of July 27, when people were most caught off guard by the torrential rain that swept away homes and lives.

Alerts were sent, phones buzzed and area residents reportedly received severe weather warnings.

According to the Iowa Environmental Mesonet, a tool that ropes in weather data from participating networks and stations, at least 28 weather warnings were sent from July 26 to July 29. Of those, 19 are verified.

Jane Marie Wix, the warning coordination meteorologist at the National Weather Service office in Jackson, confirmed at least three warnings issued in that period were upgraded all the way to “catastrophic” or a “Flash Flood Emergency.” Warnings made at that level go directly to mobile phones in the area, alerting the public to potentially imminent disaster.

Other types of notices, like the issuance for flash flood warnings, may not make it to a mobile phone alert. Wix noted that apps like RadarScope and Ring send alerts for base Flash Flood Warnings.

Many local governments and emergency services offer opt-in and other options to receive weather alerts. But there is some concern among meteorologists about “forecast fatigue,” especially given the ever temperamental nature of weather.

Forecasters and communication about extreme weather

To Lexington meteorologist Chris Bailey, forecasters’ concern about inducing “forecast fatigue” — when frequent messaging ahead of severe weather events desensitizes the public, increasing the chances they will not take action — can sometimes be a liability, especially as climate change makes severe of weather more frequent.

“There are always going to be swings and misses when it comes to forecasting,” Bailey told the Herald-Leader, adding “there has never been a greater need for forecasters to fully devote themselves to saving lives and helping the public as much as we can.”

He pushes back on some of his peers who worry about “crying wolf” too many times. In his experience, there’s a massive appetite for local weather news, especially when it comes from a forecaster who’s adept at engaging with the public, as Bailey often does on his Twitter feed.

He praised the rapid response of the forecaster on deck at the NWS station in Jackson the night of July 27, when torrential rainfall hammered down on Eastern Kentuckians as they slept, leaving devastation in its wake.

Communicating with the public is one of the challenges meteorologists navigate in a fragmented media landscape, especially as new evidence emerges that climate change may be shortening the window they have to make useful predictions about severe weather.

Climate change and weather forecasting

Scientists have long understood climate change means stronger heat waves and more powerful hurricanes, but research has only recently suggested a warming planet could also shorten the window during which useful predictions can be made by forecasters.

A study published in late 2021 by researchers at Stanford University appears to be among the first.

“It seems that colder climates are just inherently more predictable than warmer ones,” Aditi Sheshadri, an atmospheric scientist at Stanford and lead author of the paper, told The Washington Post last year.

There’s a certain amount of chaos and uncertainty about predicting the weather, or as forecaster Joshua Durkee describes it, it’s “a nonlinear science.”

Durkee, a Western Kentucky University professor and meteorologist, runs the school’s College Heights Atmospheric Observatory for Students, or CHAOS lab.

“This is a progressing science, so we’re learning every day that goes by,” Durkee told the Herald-Leader. “As with anything, when you’re learning something, it usually just raises more questions.”

Weather is local, Durkee stressed. A storm that unleashes a flash flood can only be a few miles long and wide. Other factors, like drought, can also contribute to flash flood events.

In forecasting, there are countless conditions to track, and even the most innocuous, unaccounted for detail in a weather model can grow into a seismic error. This causes the model to bend and warp like a fun-house mirror away from reality over time.

To account for this phenomenon, meteorologists will run an ensemble of models, with each one tweaked to have slightly different starting conditions. Forecasters review these branching, possible futures and see where they overlap and diverge.

When there’s a wide divergence among each of the models, accurate predictions become harder to make, Durkee said. As The Post put it, when forecasters look deeper into the future through these bundles of models, the models themselves will branch further and further apart. Eventually, they will bear as much resemblance to each other as a completely different model, assuming an entirely different set of initial conditions.

This is the point meteorologists call “error saturation” – when the machine models “forget” and “lose memory” of their starting conditions. The causal link that allows scientists to work backwards and trace the initial variables that led to the eventual outcome is no more, or as Sheshadri, the study’s lead author, writes, “thus changing the period over which weather predictions may be useful.”

The major question Sheshadri and her co-authors explore is, if in a warmer climate, weather models reach this point faster than in a colder one. The study’s scope focuses on Earth’s mid-latitudes, where the U.S., Europe and China are located.

Ultimately, the study’s authors found in warmer climates, storms grow more rapidly and errors breed faster.

“It’s time to error saturation, which is associated with the accurate window of predictability, that time scale is just shorter in a warmer climate,” Sheshadri told The Post.

Strip mining’s affect on flood disasters

Deadly flash floods aren’t unheard of in Kentucky, but in eastern part of the state, as the Mountain Eagle editorial board wrote last week, such floods seem to have been mostly bearable in pre-industrial times.

Mountains blanketed in verdant trees have a remarkable ability to gradually absorb rainwater and send the excess safely on its way, tumbling down streams that gradually join and become rivers. But in recent decades, that ability has been eroded by mountaintop removal via strip mining – a destructive project largely financed by the Tennessee Valley Authority, the Mountain Eagle editorial staff noted.

Recently, two former state and federal mining regulators urged state and federal authorities to look into the role strip mining played in magnifying the flood disaster in Eastern Kentucky, Inside Climate News reported.

These environmental factors met record rainfall across a five-day period, resulting in totals more than “600% of normal,” according to the NWS.

In its analysis of the July 28 flooding, the NWS noted upwards of 14 to 16 inches of rain fell on the region between July 25 and July 30. Many more locations received between 6 and 10 inches of rain. But instead of spreading itself over that five-day period, the NWS noted, most of this rain fell during the night of July 27 into the following morning.

This amount of rain falling in such a short period of time is incredibly rare, the NWS underscored in its analysis.

There is less than a 1 in 1,000 chance for this much rainfall over five days in a given year, the agency said.

Megan Schargorodski is Kentucky’s interim state climatologist and she directs the Kentucky Climate Center and state Mesonet system of weather stations from WKU.

As Schargorodski sees it, “the forecasters got it right.”

Weather models have become very adroit at anticipating approximately where and when weather systems will impact people on the ground, she noted. That’s true for both short-term forecasts and more seasonal outlooks.

“In (the July 25-30 flooding), the forecasters got it right. As the week progressed, the confidence grew that there would be a significant, impactful rain event in eastern Kentucky,” she wrote in an email to the Herald-Leader.

“The only real point of failure was the fact that much of this significant rainfall happened overnight, and it happened quickly due to the high rainfall rates. As with any weather that happens overnight, it is incredibly difficult to make sure the communities are getting the warnings if they are sleeping,” she continued.

Having multiple means of receiving severe weather notification can be life-saving, Schargorodski continued, but if those alerts come at night, evacuation attempts can prove dangerous amid rising waters, landslides and hazardous road conditions.

“As Kentucky’s climate is getting warmer and wetter, these extreme events will continue. There needs to be wider public engagement and training on what to do in these situations as they are happening in order to ensure safety. We have to invest in preparedness as much as mitigation of the problem,” Schargorodski wrote.

Do you have a question about climate change in Kentucky? We’d like to hear from you. Fill out our Know Your Kentucky form or email ask@herald-leader.com.