Imagine you are tasked with conducting a science experiment. But not like a middle school science fair kind of experiment. You’re asked to figure out how one of the most complex systems on planet Earth works. You need to measure it, observe it, understand it and explain why and how it does what it does. And then you need to learn how to consistently predict what it will do in the future. Where would you start?

You will need to organize dozens or possibly hundreds of scientists you’re working alongside, staying in constant communication. You’ll use complex, cutting-edge tools and high-speed computing power. You will need to be able to conduct your experiment in one location one day and perhaps two states over the next day. You’ll have to coordinate all this with scientific precision, recording every aspect in detail for later analysis. And once you’ve gathered your data, you will put it all together, figure out what it means, and tell the world about your new scientific discovery.

Now imagine the thing you are studying is a massive thunderstorm or perhaps even a violent tornado. It’s three o’clock in the afternoon but the sky is dark. The wind is howling and swirling in all directions and huge hail is starting to fall. 

You’re standing outside in these elements, face-to-face with the power of nature. 

And did we mention the storm is moving? Moving fast. Maybe even… right at you? By the way, are you getting all that data recorded?

Sounds a little overwhelming right? For the scientists and researchers at the NOAA National Severe Storms Laboratory (NSSL), it might be just another Wednesday. 

HYPOTHESES TESTED, DISCOVERIES MADE

Officially founded in 1964, NSSL is the NOAA entity tasked with studying severe weather and tornadoes. 

“Our mission is to be the world leader in observing, understanding and modeling severe thunderstorms,” said NSSL Director, Dr. DaNa Carlis. “We want to be able to equip forecasters and society as a whole with the tools necessary to minimize the impact of tornadoes and severe thunderstorms on lives and property. To accomplish this mission, our scientists have to get out into the field and face these storms up close and personal.”

Field work has been part of NSSL since its inception. In the beginning, researchers were on their own, without computer-generated models of storms or radar to track them. So to study storms, scientists had to seek them out. 

“Our field observing at NSSL started clear back in the 1970s when we were first using Doppler radar to see if we could detect rotation in thunderstorms, and verifying the collected data with actual storm observations,” said Erik Rasmussen, chief of NSSL’s Field Observing Facilities Support Division and veteran tornado research scientist of more than 30 years. “You know, back in the early days, it was just people driving in cars with paper maps and making notes and taking pictures on slide film.”

From then until today NSSL scientists have been working to capture just how and why these storms form, so they can better equip forecasters to predict them and warn the public. To do that they needed to form theories and put them to the test by learning exactly what is happening within a storm. 

“We can’t really know what’s going on in the atmosphere without going out and observing the phenomena,” said Alan Gerard, Chief of NSSL’s Warning Research and Development Division. “Whether it’s tornadoes, lightning, hail, wind, flash floods— we really have to have ground truth and the observations from the phenomena to be able to figure out what’s going on and how to better forecast and warn for it.”

NSSL research scientist Anthony Lyza adds, “Field work is essential to the work we do at NSSL because it allows us to go out and test the hypotheses. It lets us ask the questions that we have from what we learn and research in the lab and go and examine actual storms and see how accurate or inaccurate some of our ideas might be.”

Through the decades, NSSL’s field work has evolved with technology. In fact, NSSL actually invented or pioneered the use of some of that technology. From various instruments mounted on trucks called mobile mesonets, to mobile radars, lightning mapping arrays, LIDARs and even drones, working with partner agencies, universities and other NOAA entities, NSSL puts cutting edge technology to work in the field in pursuit of its mission.

“We advance science by working collaboratively,” said NSSL Research Meteorologist Sean Waugh. “When we do research, we’re constantly partnering with other people. Hey, we’re going to bring this instrument to the table, what can you bring to the table? That way we can capture different aspects of the storm rather than having to do it all ourselves. Everybody has different strengths and things that they can provide to that larger team environment.”

That cooperative attitude is crucial because the stakes are high. NSSL scientists are invested in studying storms because they want to be part of helping people stay safe and out of harm’s way. That’s what they’ve done since 1964 and what they continue to do today.

“It’s not about going out and seeing the biggest tornado or the biggest hail or, you know, getting as close as possible. That’s not why we’re out there,” said Waugh. “We’re asking questions to try to better understand those environments so that we can predict them better in the future. So we can warn people better in the future.”

For decades, NSSL has put its ideas and hypotheses to the test in the field. Some have proven correct and led to great advancements in technology and forecasting. Far more have been proven incorrect or incomplete. That’s the nature of science. But it is the dedicated, continued pursuit of that scientific process that has allowed NSSL to drive forward our understanding of these unimaginably complex storms – ultimately in the pursuit of serving the public.

“A big benefit of improved understanding of all these things inside storms would be faster, more timely warnings, more confident warnings,” Rasmussen explained. “We can look at radar now and say a tornado is about to form. A tornado has formed.”

“What we’d like to get to is looking at what’s going on in the storm aloft and say, well, those conditions could lead to that rotation in about 20 or 30 minutes and then we can give people a much longer advance notice of the potential of a tornado,” he added

NSSL STUDIES TORNADOES IN THE SOUTHEAST

Perhaps NSSL’s most significant and successful recent field campaign is PERiLS (Propagation, Evolution, and Rotation in Linear Storms), one of the largest and most comprehensive severe storm field research projects to date, taking place across the Southeast United States in the late winter and spring periods of 2022 and 2023.

Partnering with the National Science Foundation (NSF), other NOAA entities, as well as universities and other non-profit organizations, NSSL’s PERiLS project utilized dozens of different instruments and tools to observe the environment in and around severe thunderstorms. This project was particularly focused on the internal storm processes associated with tornado-producing quasi-linear convective systems (QLCSs), commonly called squall lines, that are common in the region. 

“PERiLS was quite a successful field campaign,” said Lyza, who served as the project’s coordinating scientist for NSSL.  “We went out nine times across two springs, and collected data on more than 20 tornadoes, several of which were EF3 to EF4 intensity. So we gathered a lot of data on numerous tornadoes and at close range.”

The project was part of the VORTEX-SE (Verification of the Origins of Rotation in Tornadoes Experiment – Southeast), a tornado research program focused on the southeastern United States. Storms in this region can pose a higher risk to people and property than in other parts of the country for two reasons. 

First, QLCS storms and the tornadoes they produce can be challenging to predict in advance because they often develop and evolve rapidly. Second, the southeast U.S. tends to be more vulnerable because of unique scientific and socioeconomic factors, which previous research has shown include the frequency of nighttime tornadoes, larger population density relative to other tornado-prone areas in the U.S., and the larger amount and distribution of mobile and manufactured homes that pose added risks for residents when tornadoes strike.

“When you get to the southeast U.S., the storms are completely different from the central United States,” said Rasmussen. “They’re long lines, they don’t have as much intensity to the updrafts. The tornadoes form rapidly with very few precursors, so it is really hard to apply the knowledge researchers have gained in the Great Plains to the Southeast tornado problem. And it was pretty obvious that we needed to get out there and look at those storms to understand the differences.”

During its nine operating periods, PERiLS involved hundreds of researchers, scientists and other support personnel, all coordinating to deploy numerous different instruments safely and efficiently to observe, document and analyze these storms up close and in real time. 

Researchers utilized profilers to gather information about temperature, humidity, wind speed and direction and how that changes during the course of the storm. This helped characterize things like instability and wind shear, that are important to the organization and formation of severe thunderstorms. 

Mobile radar crews deployed to form a dense network of radar observations that could provide high resolution information about the storms themselves, including rotation and the processes that lead up to it. 

Mobile mesonets – trucks that have instruments measuring temperature, humidity, pressure and wind speed and direction mounted on top of them – allowed researchers to take the equipment directly into the parts of the storm that are most interesting and will yield the most critical data. These trucks were also equipped with weather balloon systems to deploy additional instruments near storms.

PERiLS also deployed mobile lightning mapping arrays to gather data on lightning activity within the storms, and precipitation instruments to gather data on rainfall characteristics within the line of storms to see how raindrop sizes change from one part of the storm to another.

“Every field project we do, we spend months, if not years, of effort planning, budgeting, designing, building all of the equipment that we need and figuring out how many people we need to actually operate it,” said Waugh. “There’s all of this logistics. It’s like playing a giant game of chess.”

Science doesn’t stop after a storm. PERiLS used uncrewed aerial systems to gather high resolution photo and video mapping information of tornado damage tracks to connect radar and all the field instrument observations with the damage on the ground. 

Perhaps the most significant operation of the PERiLS campaign came in March of 2023, when a violent EF4 tornado hit the town of Rolling Fork, Mississippi, with NSSL researchers in place to capture data during the storm. 

“During PERiLS we were able to collect data on some very significant tornado events,,” said Gerard. “We feel like we’ve really learned a lot about the environment and some of the things that occur in the individual thunderstorms that produce these tornadoes in the southeast that are going to be able to be used by the NOAA National Weather Service and our partners to be able to produce better warnings.”

BRINGING IT HOME. TORNADO DATA COLLECTED, NOW WHAT?

All that data collected in the field presents a new challenge. After the excitement of being up close and personal with the awe-inspiring power of nature, NSSL researchers return to the lab and get to work on decoding the observations they collected. 

“The hard part begins after we get back home,” said Rasmussen. “We have to make sure the data is good quality, and then analyzing it normally takes maybe two or three times longer than it did to just go out to the field and gather it. Once you’ve analyzed it, you have to try to pull the new knowledge from it, and send it out to your fellow scientists.” 

He explained that NSSL archives the data and makes it all open to the public before performing any scientific analysis on it. 

“So it’s a long process from when we actually collect the data to when we have any answers to our science questions,” Rasmussen said.

“It’s like building a puzzle, right?” said Waugh. “If you only had one piece of a giant puzzle, you’re going to have a hard time figuring out what that whole picture is supposed to look like.

But by putting multiple pieces together and finding out how they fit and interlock, that’s when you start to see that bigger picture.” 

And that’s exactly what NSSL scientists do with the observational data they collect. 

“We come back and we look at it and we try to understand how those different observations are working together to make this environment happen or how this tornado happened, that sort of thing. It’s through that process we start to gain that understanding.”

What might it be like to be an NSSL researcher? Watch above to get in on the action and see what a day is like for these daring scientists.

Ultimately the goal of any NSSL field project is to further our mission to be the world’s preeminent laboratory for observing, understanding, and modeling severe thunderstorms. By doing so, NSSL develops the tools and techniques of the future to better equip the NOAA National Weather Service to produce life-saving forecasts and warnings. 

Having spent part of his career with the NOAA National Weather Service, Gerard has worked on both the research and operations sides of severe weather, and knows the significance of NSSL’s work and how years of dedicated science builds on itself. Going out into the field, gathering data, analyzing it, answering questions, developing new ones and repeating that process ultimately leads to the kinds of advancement and discoveries that save lives. 

“I can remember the challenge of issuing warnings before we had Doppler radar,” said Gerard. “The research that was done at NSSL observing tornadoes with mobile radar and all of the observing equipment we had, and then integrating that in a way that enabled the operational Doppler radar system to be developed and deployed is a really great example of how it’s a long game.”

He explained further, “It has made a huge impact in being able to save lives because we went from not being able to warn people in advance of a tornado, to being able to warn them in advance and enabling people to take shelter. Those are the kind of things that we’re trying to do at NSSL, connecting our field research with better warnings and forecasts.” 

NSSL is not just doing this with tornadoes, but also with flash floods, wildfires, and other storm hazards. For instance, researchers are taking mobile radars out into areas that have had wildfires to try to observe debris flows and make better forecasts and warnings for people. We’re really trying to connect our field research with better warnings and forecasts.”

Making that connection is at the essence of NSSL’s mission. 

“NSSL has been doing crucial work in the field for 60 years,” said Carlis. “The observations, discoveries, and advancement our scientists have made over the decades have led to drastic improvements in forecasting and warnings that are protecting property and saving lives every day. It’s that science and that process that is our passion and what drives us forward.”