NOAA Next Generation Radar (NEXRAD) Level III Products

Weather Radar (Level III)

browse graphicNEXRAD reflectivity image
This dataset consists of Level III weather radar products collected from Next-Generation Radar (NEXRAD) stations located in the contiguous United States, Alaska, Hawaii, U.S. territories and at military base sites. NEXRAD is a network of 160 high-resolution Doppler weather radars operated by the NOAA National Weather Service (NWS), the Federal Aviation Administration (FAA), and the U.S. Air Force (USAF). Doppler radars detect atmospheric precipitation and winds, which allow scientists to track and anticipate weather events, such as rain, ice pellets, snow, hail, and tornadoes, as well as some non-weather objects like birds and insects. NEXRAD stations use the Weather Surveillance Radar - 1988, Doppler (WSR-88D) system. This is a 10 cm wavelength (S-Band) radar that operates at a frequency between 2,700 and 3,000 MHz. The radar system operates in two basic modes: a slow-scanning Clear Air Mode (Mode B) for analyzing air movements when there is little or no precipitation activity in the area, and a Precipitation Mode (Mode A) with a faster scan for tracking active weather. The two modes employ nine Volume Coverage Patterns (VCPs) to adequately sample the atmosphere based on weather conditions. A VCP is a series of 360 degree sweeps of the antenna at pre-determined elevation angles and pulse repetition frequencies completed in a specified period of time. The radar scan times 4.5, 5, 6 or 10 minutes depending on the selected VCP. During 2008, the WSR-88D radars were upgraded to produce increased spatial resolution data, called Super Resolution. The earlier Legacy Resolution data provides radar reflectivity at 1.0 degree azimuthal by 1 km range gate resolution to a range of 460 km, and Doppler velocity and spectrum width at 1.0 degree azimuthal by 250 m range gate resolution to a range of 230 km. The upgraded Super Resolution data provides radar reflectivity at 0.5 degree azimuthal by 250 m range gate resolution to a range of 460 km, and Doppler velocity and spectrum width at 0.5 degree azimuthal by 250 m range gate resolution to a range of 300 km. Super resolution makes a compromise of slightly decreased noise reduction for a large gain in resolution. In 2010, the deployment of the Dual Polarization (Dual Pol) capability to NEXRAD sites began with the first operational Dual Pol radar in May 2011. Dual Pol radar capability adds vertical polarization to the previous horizontal radar waves, in order to more accurately discern the return signal. This allows the radar to better distinguish between types of precipitation (e.g., rain, hail and snow), improves rainfall estimates, improves data retrieval in mountainous terrain, and aids in removal of non-weather artifacts. The NEXRAD products are divided in two data processing levels. The lower Level II data are base products at original resolution. Level II data are recorded at all NWS and most USAF and FAA WSR-88D sites. From the Level II quantities, computer processing generates numerous meteorological analysis Level III products. The Level III data consists of reduced resolution, low-bandwidth, base products as well as many derived, post-processed products. Level III products are recorded at most U.S. sites, though non-US sites do not have Level III products. There are over 40 Level III products available from the NCDC. General products for Level III include the base and composite reflectivity, storm relative velocity, vertical integrated liquid, echo tops and VAD wind profile. Precipitation products for Level III include estimated ground accumulated rainfall amounts for one and three hour periods, storm totals, and digital arrays. Estimates are based on reflectivity to rainfall rate (Z-R) relationships. Overlay products for Level III are alphanumeric data that give detailed information on certain parameters for an identified storm cell. These include storm structure, hail index, mesocyclone identification, tornadic vortex signature, and storm tracking information. Radar messages for Level III are sent by the radar site to users in order to know more about the radar status and special product data. NEXRAD data are provided to the NOAA National Climatic Data Center for archiving and dissemination to users. Data coverage varies by station and ranges from May 1992 to 1 day from present. Most stations began observing in the mid-1990s, and most period of records are continuous.

Cite this dataset when used as a source.

  • NCEI DSI 7000
  • gov.noaa.ncdc:C00708
Dataset Information
Online Access
Distribution Formats
  • Native Binary
    • File Compression: Unix Zip (.Z) or gzip (.gz) compression and tape archive (.tar) may be applied to data files retreived from the NCDC archive.
  • ArcGIS
  • KMZ
DistributorDOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
Dataset  Point of Contact Customer Engagement Branch
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
1-828-271-4800
ncei.orders@noaa.gov
General Documentation
  • NEXRAD Level III Landing page
    Level-III NEXRAD data are 40+ products generated from NEXRAD Level-II data using computer algorithms at the radar sites and include base and composite reflectivity, precipitation estimates, storm relative velocity, vertical integrated liquid, hail index, tornadic vortex signature, mesocyclone identification, and echo tops along with the dual-polarization measurements of differential reflectivity, correlation coefficient and specific differential phase, hydrometer classification, and melting layer data.
Associated Resources
Publisher
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
Originator
  • DOC/NOAA/NWS/ROC > Radar Operations Center, National Weather Service, NOAA, U.S. Department of Commerce
Date(s)
  • publication: 1992
Data Presentation Form: Digital image
Dataset Progress Status On Going
Data Update Frequency: Continual
Purpose:Level-III NEXRAD data are 40+ products generated from NEXRAD Level-II data using computer algorithms at the radar sites and include base and composite reflectivity, precipitation estimates, storm relative velocity, vertical integrated liquid, hail index, tornadic vortex signature, mesocyclone identification, and echo tops along with the dual-polarization measurements of differential reflectivity, correlation coefficient and specific differential phase, hydrometer classification, and melting layer data.
Time Period:1992-05-07  to  Present
Spatial Bounding Box Coordinates:
N: 68.0
S: 11.0
E: -64.0
W: 124.0
Spatial Coverage Map:
Theme keywords
  • EARTH SCIENCE > SPECTRAL/ENGINEERING > RADAR > DOPPLER VELOCITY
  • EARTH SCIENCE > SPECTRAL/ENGINEERING > RADAR > RADAR CROSS-SECTION
  • EARTH SCIENCE > SPECTRAL/ENGINEERING > RADAR > RADAR REFLECTIVITY
  • EARTH SCIENCE > SPECTRAL/ENGINEERING > RADAR > SPECTRUM WIDTH
  • EARTH SCIENCE > SPECTRAL/ENGINEERING > SENSOR CHARACTERISTICS > VIEWING GEOMETRY
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > CYCLONES
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > HURRICANES
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > STORMS
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > TORNADOES
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PHENOMENA > TYPHOONS
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > BOUNDARY LAYER WINDS
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > CONVECTION
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > UPPER LEVEL WINDS > WIND SPEED/WIND DIRECTION
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > VERTICAL WIND MOTION
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND PROFILES
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND SHEAR
  • EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD MICROPHYSICS > CLOUD LIQUID WATER/ICE
  • EARTH SCIENCE > ATMOSPHERE > CLOUDS > CONVECTIVE CLOUDS/SYSTEMS (OBSERVED/ANALYZED) > MESOSCALE CONVECTIVE COMPLEX
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > HAIL
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION RATE
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > LIQUID PRECIPITATION > RAIN
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > SOLID PRECIPITATION > SNOW
  • EARTH SCIENCE SERVICES > ENVIRONMENTAL ADVISORIES > HYDROLOGICAL ADVISORIES > FLOODS
  • EARTH SCIENCE SERVICES > ENVIRONMENTAL ADVISORIES > WEATHER/CLIMATE ADVISORIES > SEVERE WEATHER
Data Center keywords
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
Platform keywords
  • In Situ Land-based Platforms > WEATHER STATIONS/NETWORKS > WEATHER STATIONS
Instrument keywords
  • Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Radar Sounders > NEXRAD > NEXt Generation RADar
  • Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Radar Sounders > DOPPLER RADAR
Place keywords
  • CONTINENT > NORTH AMERICA
  • CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
  • CONTINENT > ASIA > EASTERN ASIA
  • CONTINENT > ASIA > EASTERN ASIA > SOUTH KOREA
  • GEOGRAPHIC REGION > MID-LATITUDE
  • GEOGRAPHIC REGION > NORTHERN HEMISPHERE
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > AZORES
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > PUERTO RICO
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > GULF OF MEXICO
  • OCEAN > PACIFIC OCEAN > CENTRAL PACIFIC OCEAN
  • OCEAN > PACIFIC OCEAN > CENTRAL PACIFIC OCEAN > GUAM
  • OCEAN > PACIFIC OCEAN > CENTRAL PACIFIC OCEAN > HAWAIIAN ISLANDS
  • OCEAN > PACIFIC OCEAN > CENTRAL PACIFIC OCEAN > KIRIBATI
  • OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN
  • OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > BERING SEA
  • OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > GULF OF ALASKA
  • OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > OKINAWA
  • OCEAN > PACIFIC OCEAN > WESTERN PACIFIC OCEAN
  • OCEAN > PACIFIC OCEAN > WESTERN PACIFIC OCEAN > EAST CHINA SEA
  • OCEAN > PACIFIC OCEAN > WESTERN PACIFIC OCEAN > YELLOW SEA
Stratum keywords
  • VERTICAL LOCATION > BOUNDARY LAYER
  • VERTICAL LOCATION > LAND SURFACE
  • VERTICAL LOCATION > TROPOSPHERE
Use Constraints
  • Cite this dataset when used as a source.
  • NCEI cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NCEI makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty. NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Fees
  • In most cases, electronic downloads of the data are free, however fees may apply for data certifications, copies of analog materials, and data distribution on physical media.
Lineage StatementNEXRAD Level III products were collected by the NOAA National Weather Service (NWS) and are archived at the NOAA National Climatic Data Center (NCDC).
Processor
  • DOC/NOAA/NWS/ROC
Processing Steps
  • Level II data are the three meteorological base data quantities: reflectivity, mean radial velocity, and spectrum width. From these Level II data, computer processors generate numerous meteorological analysis Level III products based on the Level III product algorithms. Level II data are recorded at all NWS and several select CONUS DOD WSR-88D sites. Level III products are recorded at all U.S. sites. The data are sent to the National Climatic Data Center for archiving and dissemination.
  • NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Source Datasets
  • NWS WSR-88D Next Generation Radar (NEXRAD) Level II
    • NWS Next Generation RADar (NEXRAD) Level II Data
      NEXRAD Level II data information page.
    • Description of Source: Source Contribution: The Level II data are used in processing Level III data. Source Type: digital
    • Temporal extent used:  1992-05-07  to  present

Last Modified: 2016-07-15

For questions about the information on this page, please email: ncdc.metadata@noaa.gov