Researchers travel to Gulf of Mexico to study Hurricane Laura

A team of research scientists from the NOAA National Severe Storms Laboratory and the University of Oklahoma have traveled to the Texas-Louisiana border near the Gulf of Mexico to collect data during the landfall of Hurricane Laura.

We encourage people to visit the National Weather Service website for the latest forecast.

The team, led by OU School of Meteorology Professor Michael Biggerstaff and NSSL Research Scientist Sean Waugh, is working closely with colleagues from Texas Tech University, the University of Florida, the Center for Severe Weather Research, and the University of Alabama-Huntsville.

Data collected by the team will be shared in real-time with NOAA National Weather Service Forecast Offices and emergency managers in areas affected by the storm.

NOAA NSSL deployed a truck with weather instruments attached, known as a Mobile Mesonet, along with small portable weather platforms. The Portable In Situ Precipitation Stations, or PIPS, have sensors to measure temperature, pressure, humidity, wind speed, and direction. In addition, PIPS determine the distribution of particle sizes by using an instrument called a Parsivel disdrometer to measure the number and size of any object that falls through it.


Research vehicles parked in front of a hotel.
The NOAA NSSL Mobile Mesonet and OU SMART-Rs. (NOAA)


Team members deployed include OU Data Scientist Gordon Carrie, and Cooperative Institute Research Scientist Kim Elmore, with doctoral students Addison Alford and Noah Brauer and undergraduate students Robert Moore and Jeffrey Stevenson.

The OU researchers will collect data using mobile radar units known as SMART (Shared Mobile Atmospheric Research and Teaching) radars, operated through the Cooperative Institute for Mesoscale Meteorological Studies and the College of Atmospheric and Geographic Sciences.

The radars are used to map the maximum winds observed during landfall, determine the duration of severe winds at each location within their domain, and evaluate the impact of tornado-like mesovortices, small-scale rotational features found in storms created by surface heating. These mesovortices are often found on the inner edge of the eyewall during landfall.

Combined data from these tools can provide more insight into landfalling hurricanes, especially the severe winds hurricanes bring and the damage they may cause.

A researcher standing in a field holding a weather balloon above his head, waiting to release it.
NOAA NSSL Research Scientist Sean Waugh releases a weather balloon into the atmosphere. (NOAA)

For example, damage to homes and businesses is associated with more than just the maximum wind speed. Wind gusts, duration of extreme winds, water intrusion, and the change in wind direction experienced by a structure during a wind event all impact building damage. Different parts of the hurricane create greater gust factors than other parts.

The project is sponsored by the National Institute for Standards and Technology as part of their National Windstorm Research Initiative.

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Q&A with Researcher Cassandra Shivers-Williams

Severe weather researchers focus on more than just storms. They also study how people interpret and react to severe weather warnings and communications about severe weather.

Cassandra Shivers-Williams
Cassandra Shivers-Williams

Cassandra Shivers-Williams studies just that — how the public responds to severe weather information. One specific item she studies is how people’s individual differences in thinking affect their decisions during severe weather.

She is the first ever Peter Lamb Postdoctoral research associate at the University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies. Her work supports NOAA’s National Severe Storms Laboratory. She received a bachelor’s in psychology from Southern University and A&M College, a master’s in social psychology and a doctorate in social psychology from Howard University.

Q: How did you get into your field?

A: I have been interested in psychology since I first took abnormal psychology in high school. As I worked on my bachelor’s degree in psychology, I realized that I was more specifically interested in how people interact with each other and their environment and how these interactions influenced their decisions. Thus, I went to graduate school to earn a PhD in Social Psychology.

Q: Describe the path leading up to your current job.

A: While working on my PhD, I became a Research Fellow at the NOAA Cooperative Science Center for Atmospheric Sciences and Meteorology, and I was fortunate to be invited to help with the Spring Emergency Manager Experiment hosted in NOAA’s Hazardous Weather Testbed in NSSL. Through my experiences in the Testbed, I started developing professional connections that would later lead to an opportunity to apply for the postdoc position I have now.

Q: What is it about your job that interests you?

What interests me most in my job is the fact that I have the freedom and ability to investigate socially relevant problems that I find interesting and imperative.

Q: Tell us something that might surprise us about you.

I bowl competitively! I was practically born in a bowling alley (both of my parents bowl) and I have been bowling since I could walk. I earned scholarship money for college while competitively bowling as a kid, I attended Southern University and A&M College (my undergraduate alma mater) on a partial bowling scholarship, and I met my husband, Fero, while competing at Team USA Trials!

Q: What advice would you provide to up and coming meteorologists or others in your field?

A: I would recommend being open to collaborating and learning from others in different fields from your own, including across natural and social science boundaries. The problems facing our field today are going to require innovative and multidisciplinary solutions.

Q: What one day sticks out to you during your career? Do you remember one day in particular detail?

A: Successfully defending my dissertation! That accomplishment was a significant milestone and one I will never forget.

Q: What is one thing you couldn’t live without at work?

A: I could not live without my coworkers! I love that we all get along really well together, but I also value our differing expertise and approaches toward attacking problems. I think we compliment each other well and this helps facilitate the work we do.

Shivers-Williams talking to her coworker.
Shivers-Williams during a NOAA Hazardous Weather Testbed experiment with her coworker Kim Klockow-McClain. (Photo by James Murnan/NOAA)


Q: Where is your favorite place to be?

A: My favorite place to be is somewhere warm, sunny, and sandy! I truly enjoy traveling to other countries, especially tropical places, and experiencing different beaches and oceans as well as new cultures and food.

Q: What would you most like to tell your younger self?

A: Don’t let other people’s perceptions of you or your capabilities define who you are or stop your progress. Continue to persevere and always push yourself to be the best you that you can be!

Q: What is the best book you’ve ever read?

A: Russell, K. Y., M. Wilson, and R. E. Hall, 1992: The color complex: The politics of skin color among African Americans. Harcourt Brace Jovanovich, 200 pp.

This book brings many different issues surrounding colorism among African Americans to light and offers very honest, insightful, and critical perspectives.

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Experimental tool helps improve flash flood forecasts in the Northeast U.S.

Flash flood in Washington, D.C., in July. (Photo by Alek Krautmann, NOAA)

Floods and flash floods kill more people each year than any other severe weather hazard. And a few extra minutes of notice can make a big difference reducing deaths and economic loss. This is why researchers at NOAA’s National Severe Storms Laboratory are partnering with the NOAA National Weather Service Weather Prediction Center to test an experimental flash flood and intense rainfall forecasting tool.

The Warn-on-Forecast System, or WoFS, provides additional information different from what forecasters currently use because it is high-resolution and can update quickly. The weather model focuses on individual thunderstorms and hazards associated with those storms a few hours before they form and as they develop. Ultimately, the new tool will help forecasters issue flash flood warnings earlier.

The Norman-based researchers are collaborating with WPC and several NWS forecast offices to study how they are using WoFS in real-time when making forecast decisions, said Nusrat Yussouf, a research scientist at the University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies.

“Our evaluation process of research-to-operations back to research helps us improve experimental products,” she said.

This summer the prediction system proved its usefulness. For example, in July when parts of the Northeast and mid-Atlantic were inundated with intense rainfall, WPC forecasters used WoFS as they observed the perfect conditions for flash flooding over the I-95 corridor.

The WoF experimental system showed up to five inches of rain in some areas. The guidance Screenshot of WPC discussion where WoFS utilization is mentioned.provided through WoFS gave forecasters more confidence to use the phrase “flash flooding likely” when they issued area forecasts for parts of Pennsylvania and New Jersey, down to Baltimore, Washington D.C and Virginia. The storms resulted in flooded roads during rush hour, stranded motorists, cancelled and delayed flights, power outages and property damage.

This short-term exploration of the experimental WoFS’s capabilities in NWS operations is valuable for researchers at NSSL and OU CIMMS. Yussouf, whose work supports NSSL, said researchers cannot easily study NWS forecasters’ natural decision-making process in a controlled testbed environment.

“The traditional testbed experiment environments are more controlled with a routine start and end time,” she said. “We’ve created something more organic in operations that gives us insights into how that decision process occurs and how the WoF workflow may look in NWS operations in the future.”

Forecasters provide feedback to researchers throughout the experiment, including products they would like to see and what does or does not work well for them.

Yussouf said the collaboration with WPC is mutually beneficial since the Center focuses on intense rainfall and flash flooding events.

“Our goal is to help provide forecasters more tools to save lives and property,” Yussouf said. “This is one more tool to help them.”

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Collaboration with Taiwanese agency foundational to NSSL’s MRMS system

Recently a delegation from the Taiwan Central Weather Bureau and Soil and Water Conservation Bureau  visited NSSL for a project review. The visitors include the director of the CWB Meteorological Satellite Center, the director of the SWCB Debris Flow Disaster Prevention Center, one research meteorologist from CWB and two engineers from SWCB. NSSL scientists provided briefings on the latest Multi-Radar Multi-Sensor research and development efforts, and the visitors discussed their operational needs and challenges related to hydrological predictions in a tropical region with complex terrain.

Collaboration is a fundamental aspect of research at NOAA National Severe Storms Laboratory and recently a group from Taiwan’s Central Weather Bureau and Soil and Water Conservation Bureau visited the lab in Norman, Oklahoma.

The partnership between NSSL and CWB began 16 years ago when both agencies worked to develop and implement an early Multi-Radar Multi-Sensor System version and integrate it into CWB’s radars.

The collaboration grew with the joint interest in developing advanced quantitative precipitation estimate applications to address heavy precipitation over complex terrain associated with typhoons and hurricanes,” said Kenneth Howard, research scientist with NSSL. “The CWB collaboration was foundational to NSSL’s research and development of MRMS system operationally deployed in the United States.”

Such collaborations are important because the atmosphere does not stop at geographical borders.

“These partnerships and opportunities expand our knowledge of advancements in weather and hydrological research and operations around the world,” said Jian Zhang, research meteorologist. “Further, the collaborations leverage resources and expertise in different agencies for a more effective research and development effort to address challenges for different geographical and climatological regions.”

The recent visit provided an opportunity for each agency to present an update on projects and to review progress. The mid-term review allows the CWB project managers to meet with the various participating NOAA agencies in the U.S. This year SWCB joined the review and visited NSSL and the Global Systems Division of NOAA’s Earth Systems Research Laboratory in Colorado.

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Hurricane Harvey offers unprecedented data for NSSL researcher

As Hurricane Harvey came ashore along the Texas coast, NOAA National Severe Storms Laboratory Researcher Sean Waugh managed to do what no one has done before — he launched a weather balloon in the eye of the hurricane. The data recorded by the balloon’s instruments as it circled Harvey’s eyewall were record-breaking and confusing, and will require time and research to explain.

“This was the first observation of its kind,” Waugh said. “No one has ever seen this type of data, some of the values are exceptionally high and we are still trying to determine what those values mean.”

An image of the observations NOAA NSSL Researcher Sean Waugh saw after launching a weather balloon in the eye of the hurricane. (Photo by Sean Waugh/NOAA NSSL)

The eyewall is the edge of the eye of the hurricane — the strongest area of the storm. Two measurements from the balloon launch were particularly interesting. The first was a wind profile that produced computed values higher than ever observed, indicating its use in these circumstances may not be correct. The second, a measurement of potential rain, was also extreme, and may have been an early indication of the unprecedented flooding produced by Harvey.

The NOAA NSSL mobile mesonet in Texas before Hurricane Harvey came ashore. (Photo by Sean Waugh/NOAA NSSL)

The balloon launch was one part of Waugh’s efforts to collect data in the path of Hurricane Harvey. From a truck with roof mounted instruments called a mobile mesonet, he recorded observations of rain, wind, temperature and humidity for an extended period of time.

Gathering the data was not a task for the faint of heart. Before and after the balloon launch, Waugh experienced high winds — nearly 100 miles per hour — while sitting in the heavy mobile mesonet truck.

Waugh coordinated on this project with scientists from The University of Oklahoma College of Atmospheric and Geographic Sciences. The university team collected data with their radar-equipped truck.

Over time, Waugh hopes to better understand this unprecedented data set, and how it can contribute to a greater understanding of hurricanes and the tornadoes they produce.

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International collaboration benefits US, European forecasters

NOAA National Severe Storms Laboratory Researcher Adam Clark at the European Severe Storms Laboratory Testbed this summer.

Weather doesn’t stop at borders. Nowhere is this more clear than in Europe, where two researchers working at the NOAA National Severe Storms Laboratory went shoulder to shoulder with researchers in the European Severe Storms Laboratory Testbed this summer. The goal was to collaborate on forecast products and learn how NSSL technologies are used abroad.

“As scientists and meteorologists, we need to continue to talk because that’s how true knowledge transfer occurs,” said Darrel Kingfield, University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies researcher working at NSSL. “ESSL researchers came to work with us in the NOAA Hazardous Weather Testbed a couple of years ago and this year we went to them.”

Darrel Kingfield presenting at the European Severe Storms Laboratory Testbed this summer.

During its sixth year, the ESSL Testbed program evaluated forecasts for high-impact weather. Like the HWT, the ESSL testbed serves as a forum to stimulate interaction between product developers and operational forecasters from throughout Europe. Also, lectures from several local and international experts help testbed participants enhance their knowledge and skills.

Different geography, systems

Kingfield and NSSL Research Scientist Adam Clark each spent a full week at ESSL’s testbed. What struck them was the difference in geography between the United States and Europe. Clark said ingredients needed for severe weather come together much differently in Europe than the U.S.

“You have the Mediterranean Sea and the Alps and that affects much of their weather,” Clark said.

Adam Clark working in the European Severe Storms Laboratory Testbed.

Along with geographical differences, Clark and Kingfield learned about the different weather prediction and monitoring systems operated by each European country. A variety of forecasting tools and methods are used throughout Europe, from government operated to privatized systems. This results in data, forecasting and verification inconsistencies.

“For example, after a tornado occurs in the U.S., officials observe and record where it occurred and how severe it was,” Kingfield explained. “Europeans rarely go out and assess tornado damage after a storm. Those surveys are reserved for most damaging events.”

As a result, Europe’s tornado database is not nearly as complete as the United States.

Sharing tools and techniques
While in the testbed, Kingfield and Clark gazed upon a few familiar products.

“The German Weather Service is using a lot of the same techniques developed at NSSL to interpret radar data,” Kingfield said. Some European meteorologists use several products developed in the U.S. by NSSL and OU CIMMS researchers. For instance, one technique allows them to use radar data to visualize the possible track of a tornado based on the storm’s rotation.

Collaboration is an important tool for forecasters and researchers. Participation in ESSL’s testbed allows researchers like Kingfield and Clark to share new technologies, experience new techniques and learn new systems. Opportunities like this allow researchers to collaborate on new products and technology, ultimately leading to better forecasts and warnings for the American public.

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Researchers evaluating lightning data in Hazardous Weather Testbed

For the first time ever, lightning data from a weather satellite is available and being evaluated in the NOAA Hazardous Weather Testbed.

Forecasters, researchers, product developers and broadcast journalists are analyzing recently available experimental data from an instrument on GOES-16, the newly launched NOAA satellite as part of the HWT Experimental Warning Program.

GOES-16, launched by NASA last November, scans the skies five times faster than NOAA’s current geostationary weather satellites and provides images at four times greater resolution.

The higher resolution allows forecasters to see more details in storm systems, particularly during periods of rapid strengthening or weakening. GOES-16 is also the first to carry a lightning detector in geostationary orbit.

The Geostationary Lightning Mapper observes total lightning, meaning in-cloud and cloud-to-ground lightning. GLM can help increase the accuracy of forecasts and warning times when combined with other forecaster tools.

The HWT EWP GOES-16 experiment just wrapped up its second of four weeks. Kristin Calhoun, CIMMS research scientist working at NSSL, said this is the first time forecasters have seen GLM data from GOES-16.

“We are here to test it and to contribute anything from ideas for data integration to training needs,” Calhoun said. “We want people to identify as many training gaps as possible.”

Bill Line, a meteorologist with the NOAA National Weather Service Pueblo forecast office, said if people like him learn to use GLM’s data, it will better his forecasts.

“These are new tools and we want to make sure forecasters are ready to use them,” he said. “There are many combinations of data and probabilities they haven’t looked at before.”

David Stark, a meteorologist with the NOAA National Weather Service New York forecast office, in the Hazardous Weather Testbed working with GLM data. (Photo by James Murnan/NOAA)

That is the purpose of the HWT – the facility allows end users to test new, experimental products before they are released to the NWS or other NOAA entities and partners.

“We’ve held similar experiments in the past but with proxy data,” Calhoun said. “This is the first year we are able to use real data. Ideally we will continue experiments like this, using real GOES-16 data, for years to come.”

David Stark, a meteorologist with the NWS New York forecast office, participated in the first week’s experiment. He described the experience as outstanding.

“Testing out some new products and helping fine tune them so they just aren’t thrown into the NWS is great,” he said. “To be able to see these tools and see the new research, while acting like I’m issuing warnings in an area gives me a good idea and feel of what I could be doing with this in real life and how it would enhance our current products.”

Stark said the product helps better show storm formations, providing the forecaster with a better idea of when and where a storm may form.

“This would add more confidence to my forecasts and allow me to focus more on increasing warning on possible life-threatening storms,” Stark said.

The GOES-16 experiment continues in the NOAA Hazardous Weather Testbed through July 21.

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Collaboration improves UK and US radar techniques to improve forecasts

The national weather radar system used throughout the United States by NOAA National Weather Service  forecasters to “see” weather across the country is unique because it can be upgraded and modified with the newest capabilities, unlike other systems worldwide.

Because of this, and the need to work with experts in radar signal processing for improving the quality of radar data, international partners from the United Kingdom Met Office are collaborating with researchers from The University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies at the NOAA National Severe Storms Laboratory to develop new techniques for U.K.-based radars.

The U.K. Met Office operated a radar system that did not allow changes and was considered a “commercial off-the-shelf solution.”

“Most weather services in the world purchase radar systems from companies and in those systems, the signal processor is typically a black box,” said Sebastian Torres, senior research scientist with OU CIMMS and NSSL. “The signal processor is a key component in all weather radar systems. Its job is to convert echoes received by the radar into weather images. It’s something most weather services don’t really have access to. They know how it works but they can’t change or improve anything.”

The U.K. Met Office decided to build its own signal processor for their radar systems. This allows a similar degree of flexibility to that of the NEXRAD radars, also known as the WSR-88D (weather surveillance radar-88 Doppler), operated in the United States. NOAA offered some of its tested techniques to the U.K. Met Office and in return received access to valuable data it could use for future research and operations.

Inside every NEXRAD radar is a rotating parabolic antenna. As the antenna rotates, it travels up and around while sending out pulses of electromagnetic energy. When radars send and receive these pulses, buildings and other structures may obstruct the radar’s view, contaminating the storm data.

To help keep unwanted objects from impacting storm data, Torres and fellow CIMMS Researcher David Warde developed two complementary signal-processing techniques for the WSR-88D. One technique, called CLEAN-AP, or Clutter Environment Analysis using Adaptive Processing filter, removes unwanted radar echoes from objects on the ground. The other one, called WET or Weather Environment Thresholding, intelligently decides when the CLEAN-AP filter should be applied. This prevents slow-moving storms from being confused with stationary objects.

NSSL and CIMMS researchers Sebastian Torres and David Warde (second and third person from the left) visited the UK Met Office in Exeter from February 22-26, 2016 to support implementation of CLEAN-AP on the UK weather radar network.


“The goal of CLEAN-AP and WET is to clean the data as much as possible so the forecasters have the best data available to make warnings and forecasts,” Torres said.

Through collaboration with the U.K. Met Office, who implemented CLEAN-AP and WET, the techniques were fine-tuned and improved. Both techniques are being transferred to the NOAA National Weather Service, and CLEAN-AP is licensed by OU to U.S. weather radar manufacturer Baron.

CLEAN-AP before and after


Another CIMMS Researcher, Igor Ivic, developed a third product transferred to the U.K. called the Radial-by-Radial Noise Estimator. RBRN  improves the quality of radar data by removing “noise,” the radar equivalent of radio static or television static. It was implemented on the U.S. NEXRAD network as part of ongoing research-to-operations efforts at NSSL and CIMMS.

“If you have noise and you can remove it from the radar returns, then you get just the signal, and that can be used to get better quality data,” Torres said.

Torres called the collaboration a “win-win” situation because the information exchange, as well as the new technologies and techniques that have been developed are good for both the U.S. and U.K.

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CI-FLOW total water level system prepared for test by Tropical Storm


Researchers with the Coastal and Inland Flooding Observation and Warning (CI-FLOW; project are preparing for Tropical Storm Hermine to test their total water level system in North Carolina this weekend. The CI-FLOW system captures the complex interaction between rainfall, river flows, waves, tides and storm surge, and how they impact water levels in the Tar-Pamlico and Neuse Rivers and the Pamlico Sound in North Carolina.

CI-FLOW collects data from a computing system that combines radar and rain gauge information to create estimates of rainfall. This information is passed on to water quantity models that simulate freshwater flows from the headwaters of the basins into the rivers; taking into account soil type, slope of the land and vegetation patterns. Finally, water flow data is passed from river models to a coastal circulation and storm surge model that provides simulations of waves, tides and storm surge.

National Weather Service forecasters will have access to CI-FLOW during Tropical Storm Hermine to help them evaluate the system for application in the flood and flash flood warning process.

The CI-FLOW project is motivated by NOAA’s critical forecast need for detailed water level predictions in coastal areas and has a vision to transition CI-FLOW research findings and technologies to other U.S. coastal watersheds.

The NOAA National Severe Storms Laboratory, with support from the NOAA National Sea Grant Office, collaborates with the unique interdisciplinary team including the North Carolina, South Carolina, and Texas Sea Grant Programs, University of Oklahoma, Renaissance Computing Institute (RENCI), University of North Carolina at Chapel Hill, Seahorse Coastal Consulting, NWS Forecast Offices in Raleigh and Newport/Morehead City, NWS Southeast River Forecast Center, NOAA’s Office for Coastal Management, NOAA in the Carolinas, NOAA Southeast and Caribbean Regional Team (SECART), NOAA-Integrated Ocean Observing System, Department of Homeland Security Coastal Resilience Center
of Excellence, Centers for Ocean Sciences Education Excellence SouthEast, Coast Survey Development Laboratory and NWS Office of Hydrologic Development.

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