The National Severe Storms Laboratory (NSSL) is a National Oceanic and Atmospheric Administration (NOAA) weather research laboratory under the Office of Oceanic and Atmospheric Research. It is one of seven NOAA Research Laboratories (RLs).^[1]

NSSL studies weather radar, tornadoes, flash floods, lightning, damaging winds, hail, and winter weather out of Norman, Oklahoma, using various techniques and tools in their HWT, or Hazardous Weather Testbed. NSSL meteorologists developed the first doppler radar for the purpose of meteorological observation, and contributed to the development of the NEXRAD (WSR-88D).

NSSL has a partnership with the Cooperative Institute for Severe and High-Impact Weather Research and Operations (CIWRO) at the University of Oklahoma that enables collaboration and participation by students and visiting scientists in performing research.^[2] The Lab also works closely with the Storm Prediction Center (SPC) and the National Weather Service Norman Forecast Office, which are co-located at the National Weather Center (NWC) in Norman, Oklahoma.^[2] The NWC houses a combination of University of Oklahoma, NOAA and state organizations that work in collaboration.

History

In 1962 a research team from the United States Weather Bureau's National Severe Storms Project (NSSP) moved from Kansas City, Missouri to Norman, Oklahoma, where, in 1956, the Cornell Aeronautical Laboratory had installed a 3 cm continuous-wave Doppler Weather Surveillance Radar-1957 (WSR-57). This radar was designed to detect very high wind speeds in tornadoes, but could not determine the distance to the tornadoes. In 1963, the Weather Radar Laboratory (WRL) was established in Norman and, in the following year, engineers modified the radar to transmit in pulses. The pulse-Doppler radar could receive data in between each transmit pulse, eliminating the need for two antennas and solving the distance problem.^[3]

In 1964, the remainder of the NSSP moved to Norman, where it merged with WRL and was renamed the National Severe Storms Laboratory (NSSL). Dr. Edwin Kessler became the first director.^[3] In 1969, NSSL obtained a surplus 10-cm pulse-Doppler radar from the United States Air Force. This radar was used to scan and film the complete life cycle of a tornado in 1973. By comparing the film with velocity images from the radar, the researchers found a pattern that showed the tornado beginning to form before it could be visually detected on the film. The researchers named this phenomenon the Tornado Vortex Signature (TVS).^[3] Research using this radar led to the concept that would later go on to become the NWS NEXRAD WSR-88D radar network. In 1973, the Laboratory commissioned a second Doppler weather radar, named the Cimarron radar, located 15 miles (24 km) west of Oklahoma City. This enabled NSSL to perform dual Doppler experiments while scanning storms with both radars simultaneously.^[3] A deliberate decision to collocate research with operations led the National Severe Storms Forecast Center to move from Kansas City to Norman in 1997, changing its name to the Storm Prediction Center.^[3] This move would allow for improved collaborations between NSSL and SPC. Some three years later in 2000, the first NOAA Hazardous Weather Testbed (HWT) Spring Experiment took place. This would become an annual event to evaluate operational and experimental models and algorithms with the NWS.

Organization

NSSL is organized into three primary divisions:

• Forecast Research & Development Division
• Radar Research & Development Division
• Warning Research & Development Division

Forecast Research & Development

FACETs

Forecasting a Continuum of Environmental Threats (FACETs) serves as a broad-based framework and strategy to help focus and direct efforts related to next-generation science, technology and tools for forecasting environmental hazards. FACETS will address grid-based probabilistic threats, storm-scale observations and guidance, the forecaster, threat grid tools, useful output, effective response, and verification.

Warn-on-Forecast

The Warn-on-Forecast (WoF) research project aims to deliver a set of technologies for FACETs on a variety of space and time scales. WoF aims to create computer-model projections that accurately predict storm-scale phenomena such as tornadoes, large hail, and extremely localized rainfall. If Warn-on-Forecast is successful, forecasts likely could improve lead time by factors of 2 to 4 times.

NSSL-WRF

The Weather Research and Forecast (WRF) model is the product of a collaboration between the meteorological research and forecasting communities. Working at the interface between research and operations, NSSL scientists have been some of the main contributors to WRF development efforts and continue to provide operational implementation and testing of WRF. The NSSL WRF generates daily, real-time 1- to 36-hour experimental forecasts at a 4 km resolution of precipitation, lightning threat, and more.

WoF Tornado Threat Prediction

WoF Tornado Threat Prediction (WoF-TTP) is a research project to develop a 0–1 hour, 1-km resolution suite of high detail computer models to forecast individual convective storms and their tornadic potential. Target future average lead-time for tornado warnings via WoF-TTP is 40–60 minutes. The technology and science developed to achieve the WoF-TTP goal hopes to improve the prediction of other convective weather threats such as large hail and damaging winds.

NME

NSSL's Mesoscale Ensemble (NME) is an experimental analysis and short-range ensemble forecast system. These forecasts are designed to be used by forecasters as a 3-D hourly analysis of the environment.

Q2

The National Mosaic and Multi-sensor Quantitative Precipitation Estimation (NMQ) system uses a combination of observing systems ranging from radars to satellites on a national scale to produce precipitation forecasts. NMQ's prototype QPE products are also known as “Q2” - next-generation products combining the most effective multi-sensor techniques to estimate precipitation.

NEXRAD

NSSL scientists helped develop the Weather Surveillance Radar - 1988 Doppler (WSR-88D) radars, also known as NEXt-generation RADar (NEXRAD). Since the first Doppler weather radar became operational in Norman in 1974, NSSL has worked to extend its functionality, and proved to the NOAA National Weather Service (NWS) that Doppler weather radar was important as a nowcasting tool. The NWS now has a network of 158 NEXRADs.

Dual-Polarized Weather Radar (Dual-Pol)

Dual-polarized (dual-pol) radar technology is truly a NOAA-wide accomplishment. NSSL spent nearly 30 years researching and developing the technology. The National Weather Service (NWS) and NSSL developed the specifications for the modification, which was tested by engineers at the NWS Radar Operations Center. The NWS Warning Decision Training Branch provided timely and relevant training to all NWS forecasters who would be using the technology. The upgraded radars offer 14 new radar products to better determine the type and intensity of precipitation, and can confirm tornadoes are on the ground causing damage. Dual-pol is the most significant enhancement made to the nation's radar network since Doppler radar was first installed in the early 1990s.

Multi-Function Phased Array Radar (MPAR)

More than 350 FAA radars and by 2025, nearly 150 of the nation's Doppler weather radars will need to be either replaced or have their service life extended. Phased array radars have been used by the military for many years to track aircraft. NSSL's MPAR program is investigating to see if both the aircraft surveillance and weather surveillance functions can be combined into one radar. Combining the operational requirements of these various radar systems with a single technology solution^[buzzword] would result in fiscal savings, and lesser resources with a greater end result.^{[citation needed]}

Mobile Radar

NSSL researchers teamed up with several universities to build a mobile Doppler radar: a Doppler radar mounted on the back of a truck. The mobile radar can be driven into position as a storm is developing to scan the atmosphere at low levels, below the beam of WSR-88D radars. NSSL has used mobile radars to study tornadoes, hurricanes, dust storms, winter storms, mountain rainfall, and even biological phenomena.

Warning Research & Development

FACETs

Forecasting a Continuum of Environmental Threats (FACETs) serves as a broad-based framework and strategy to help focus and direct efforts related to next-generation science, technology and tools for forecasting environmental hazards. FACETs will address grid-based probabilistic threats, storm-scale observations and guidance, the forecaster, threat grid tools, useful output, effective response, and verification.

MYRORSS

The Multi-Year Reanalysis Of Remotely-Sensed Storms (MYRORSS – pronounced “mirrors”) NSSL and the National Climatic Data Center (NCDC) to reconstruct and evaluate numerical model output and radar products derived from 15 years of WSR-88D data over the coterminous U.S. (CONUS). The end result of this research will be a rich dataset with a diverse range of applications, including severe weather diagnosis and climatological information.

Hazardous Weather Testbed

NOAA's Hazardous Weather Testbed (HWT) is jointly managed by NSSL, the Storm Prediction Center (SPC) and the National Weather Service Oklahoma City/Norman Weather Forecast Office (OUN) on the University of Oklahoma campus inside the National Weather Center. The HWT is designed to accelerate the transition of promising new meteorological insights and technologies into advances in forecasting and warning for hazardous mesoscale weather events throughout the United States.

Threats in Motion

One of the new warning methodologies being tested in the NOAA Hazardous Weather Testbed is the “Threats-In-Motion” (TIM) concept. TIM warning grids update every minute and move continuously with the path of the storm. TIM has the advantage of providing useful lead times for all locations downstream of the hazards, and continually removes the warning from areas where threat has already passed.

FLASH

The Flooded Locations And Simulated Hydrographs Project (FLASH) was launched in early 2012 to improve the accuracy and timing of flash flood warnings. FLASH uses forecast models, geographic information, and real-time high-resolution, accurate rainfall observations from the NMQ/Q2 project to produce flash flood forecasts at 1-km/5-min resolution. FLASH project development continues to be an active collaboration between members of NSSL's Stormscale Hydrometeorology and Hydromodeling Groups, and the HyDROS Lab at the University of Oklahoma.

CI-FLOW

The Coastal and Inland Flooding Observation and Warning (CI-FLOW) project is a demonstration projection that predicts the combined effects of coastal and inland floods for coastal North Carolina. CI-FLOW captures the complex interaction between rainfall, river flows, waves, and tides and storm surge, and how they will impact ocean and river water levels. NSSL, with support from the NOAA National Sea Grant, leads the large and unique interdisciplinary team.

Decision Support

In an effort to support NWS forecasters, NSSL investigates methods and techniques to diagnose severe weather events more quickly and accurately.

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