NEXRAD

Last updated
NEXRAD
LabNexrad.jpg
NEXRAD Radar at the WSR-88D Radar Operations Center.
Country of origin United States
Introduced1988 (1988)
No. built160 in the US, some around the world
Type Weather radar
Frequency2,700 to 3,000 MHz (S band)
PRF 320 to 1,300 Hz (according to VCP)
Beamwidth 0.96° with 2.7 GHz
0.88° with 3.0 GHz
Pulsewidth1.57 to 4.57 μs (according to VCP)
RPM3
Range460 km for reflectivity
230 km for Doppler velocity
Diameter8.54 m (28.0 ft)
Azimuth 0 to 360º
Elevation-1° to +20° (operations)
up to +60° (test)
Power750 KW
Other NamesWSR-88D

NEXRAD or Nexrad (Next-Generation Radar) is a network of 160 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce, the Federal Aviation Administration (FAA) within the Department of Transportation, and the U.S. Air Force within the Department of Defense. Its technical name is WSR-88D (Weather Surveillance Radar, 1988, Doppler).

Contents

NEXRAD detects precipitation and atmospheric movement or wind. It returns data which when processed can be displayed in a mosaic map which shows patterns of precipitation and its movement. The radar system operates in two basic modes, selectable by the operator – a slow-scanning clear-air mode for analyzing air movements when there is little or no activity in the area, and a precipitation mode, with a faster scan for tracking active weather. NEXRAD has an increased emphasis on automation, including the use of algorithms and automated volume scans.

Deployment

Testbed of the WSR-88D on display at the National Severe Storms Laboratory. Wea03317 - Flickr - NOAA Photo Library.jpg
Testbed of the WSR-88D on display at the National Severe Storms Laboratory.

In the 1970s, the U.S. Departments of Commerce, Defense, and Transportation, agreed that to better serve their operational needs, the existing national radar network needed to be replaced. The radar network consisted of WSR-57 developed in 1957, and WSR-74 developed in 1974. Neither system employed Doppler technology, which provides wind speed and direction information.

The Joint Doppler Operational Project (JDOP) was formed in 1976 at the National Severe Storms Laboratory (NSSL) to study the usefulness of using Doppler radar to identify severe and tornadic thunderstorms. Tests over the next three years, conducted by the National Weather Service and the Air Weather Service agency of the U.S. Air Force, found that Doppler radar provided much improved early detection of severe thunderstorms. A working group that included the JDOP published a paper providing the concepts for the development and operation of a national weather radar network. In 1979, the NEXRAD Joint System Program Office (JSPO) was formed to move forward with the development and deployment of the proposed NEXRAD radar network. That year, the NSSL completed a formal report on developing the NEXRAD system. [1] [2]

When the proposal was presented to the Reagan administration, two options were considered to build the radar systems: allow corporate bids to build the systems based on the schematics of the previously developed prototype radar or seek contractors to build their own systems using predetermined specifications. The JSPO group opted to select a contractor to develop and produce the radars that would be used for the national network. Radar systems developed by Raytheon and Unisys were tested during the 1980s. However, it took four years to allow the prospective contractors to develop their proprietary models. Unisys was selected as the contractor, and was awarded a full-scale production contract in January 1990. [1] [2]

NEXRAD sites within the Contiguous U.S. NEXRAD NETWORK.jpg
NEXRAD sites within the Contiguous U.S.
NEXRAD sites in Alaska, Hawaii, U.S. territories, and military bases. NEXRAD NON-CONTIGUOUS.jpg
NEXRAD sites in Alaska, Hawaii, U.S. territories, and military bases.

Installation of an operational prototype was completed in the fall of 1990 in Norman, Oklahoma. The first installation of a WSR-88D for operational use in daily forecasting was in Sterling, Virginia on June 12, 1992. The last system deployed as part of the installation program was installed in North Webster, Indiana on August 30, 1997. In 2011, the new Langley Hill NEXRAD was added at Langley Hill, Washington to better cover the Pacific Coast of that area; [3] other radars also filled gaps in coverage at Evansville, Indiana and Ft. Smith, Arkansas, following the initial installations.[ citation needed ] The site locations were strategically chosen to provide overlapping coverage between radars in case one failed during a severe weather event. Where possible, they were co-located with NWS Weather Forecast Offices (WFOs) to permit quicker access by maintenance technicians. [4]

The NEXRAD radars incorporated a number of improvements over the radar systems that were previously in use. The new system provided Doppler velocity, improving tornado prediction ability by detecting rotation present within the storm at different scan angles. It provided improved resolution and sensitivity, enabling operators to see features such as cold fronts, thunderstorm gust fronts, and mesoscale to even storm scale features of thunderstorms that had never been visible on radar. The NEXRAD radars also provided volumetric scans of the atmosphere allowing operators to examine the vertical structure of storms and could act as wind profilers by providing detailed wind information for several kilometers above the radar site. The radars also had a much increased range allowing detection of weather events at much greater distances from the radar site. [5]

WSR-88D development, maintenance, and training are coordinated by the NEXRAD Radar Operations Center (ROC) located at the National Weather Center (NWC) in Norman, Oklahoma. [6]

The University of Louisiana - Monroe operates a "WSR-88D clone" radar that is used by the NWS to fill the coverage gap in northeastern LA, southeastern AR, and western MS. However, the status of the radar being in the NEXRAD network is disputed.

Radar properties

A standard WSR-88D operates in the S band, at a frequency of around 2800 MHz, with a typical gain around 53 dB using a center-fed parabolic antenna. The pulse repetition frequency (PRF) varies from 318 to 1300 Hz with a maximum power output of 700 kW at Klystron output, although dependent on the volume coverage pattern (VCP) selected by the operator. All NEXRADs have a dish diameter of 9.1 m (30 ft) and an aperture diameter of 8.5 m (28 ft). Using the predetermined VCPs, NEXRADs have a traditional elevation minimum and maximum ranging from 0.1 to 19.5 degrees, although the non-operational minimum and maximum spans from −1 to +45 degrees. Unlike its predecessor, the WSR-74, the antenna can not be manually steered by the operator. WSR-88D Level I data is the recorded output of the digital receiver. [7] Spatial resolution varies with data type and scan angle – level III data has a resolution of 1 km x 1 degree in azimuth, while super-res level II, (implemented in 2008 nationwide), has a resolution of 250m by 0.5 degrees in azimuth below 2.4 degrees in elevation. [8]

Scan strategies

The NEXRAD radar system continually refreshes its three-dimensional database via one of several predetermined scan patterns. These patterns have differing PRFs to fit the respective use, but all have a constant resolution. Since the system samples the atmosphere in three dimensions, there are many variables that can be changed, depending on the desired output. With all traditional VCPs, the antenna scans at a maximum of 19.5 degrees in elevation, and a minimum of .5, with some coastal sites scanning as low as .2 or lower. Due to the incomplete elevation coverage, a phenomenon known as "The Cone of Silence" is present with all NEXRAD radars. [9] The term describes the lack of coverage directly above the radar sites.

There are currently seven Volume Coverage Patterns (VCP) available to NWS meteorologists, with an eighth in the process of replacing one of the existing seven. Each VCP is a predefined set of instructions that control antenna rotation speed, elevation angle, transmitter pulse repetition frequency and pulse width. The radar operator chooses from the VCPs based on the type of weather occurring:

VCPScan time (min)Elevation scansElevation angles (°)UsageSAILS available?
124.2 [12] 140.5, 0.9, 1.3, 1.8, 2.4, 3.1, 4, 5.1, 6.4, 8, 10, 12.5, 15.6, 19.5Severe weather, including tornadoes, located closer to the radar (within 85 miles for storms traveling up to 55 MPH, but shorter distances for faster-moving precipitation)Yes (up to three per volume scan) [12]
2124.5 [13] Severe weather, including tornadoes, over 70 miles away from the radar, or widespread severe convection. Best VCP for MRLE use. Completion time for VCP 212 + 1 SAILS scan is similar to VCP 12 + 2 SAILS scans
1125.5 [14] Variant of VCP 212 designed for tropical systems and strong, non-severe wind shear events. Uses a combination of MPDA and SZ-2 to form a contiguous velocity display. [14] MRLE use is not possible with this VCPYes (up to one per volume scan)
2156 [11] 150.5, 0.9, 1.3, 1,8, 2.4, 3.1, 4, 5.1, 6.4, 8, 10, 12, 14, 16.7, 19.5General-purpose precipitation, including tropical systems capable of producing tornadoes. Most vertical resolution of any VCPYes (up to one per volume scan)
121690.5, 1.5, 2.4, 3.4, 4.3, 6, 9.9, 14.6, 19.5Legacy VCP, originally designed for tropical systems. Has significant gaps in vertical resolution above 6°. Scan strategy ensures 20 rotations in six minutes, heavily wearing antenna mechanical components. Similar completion time to VCP 215. To be replaced by VCP 112No
311050.5, 1.5, 2.4, 3.4, 4.3Long-pulse clear air mode designed for maximum sensitivity. Excellent for detecting light snow or subtle boundaries. Prone to detecting ground clutter. May be prone to detecting virga No
32Short-pulse clear air mode designed for clear air or isolated light rain and/or wintry precipitation. Ideal to use when no precipitation is in the radar range, to reduce wear on antenna mechanical componentsNo
357 [11] 70.5, 0.9, 1.3, 1,8, 2.4, 3.1, 4, 5.1, 6.4Short-pulse clear air VCP designed for scattered to widespread light to moderate precipitation from non-convective cloudforms, especially nimbostratus. Not recommended for convection, except for pop-up thundershowers produced by Cumulus congestus clouds located 30 miles or more away from the radarYes (up to one per volume scan)

The specific VCP currently in use at each NEXRAD site is available. [15]

Enhancements

Super resolution

Deployed from March to August 2008 with all level II data, [16] the Super Resolution upgrade permitted the capability of the radar to produce much higher resolution data. Under legacy resolution, the WSR-88D provides reflectivity data at 1 km (0.62 mi) by 1 degree to 460 km (290 mi) range, and velocity data at 0.25 km (0.16 mi) by 1 degree to a range of 230 km (140 mi). Super Resolution provides reflectivity data with a sample size of 0.25 km (0.16 mi) by 0.5 degree, and increase the range of Doppler velocity data to 300 km (190 mi). Initially, the increased resolution is only available in the lower scan elevations. Super resolution makes a compromise of slightly decreased noise reduction for a large gain in resolution. [17]

The improvement in azimuthal resolution increases the range at which tornadic mesoscale rotations can be detected. This allows for faster lead time on warnings and extends the useful range of the radar. The increased resolution (in both azimuth and range) increases the detail of such rotations, giving a more accurate representation of the storm. Along with providing better detail of detected precipitation and other mesoscale features, Super Resolution also provides additional detail to aid in other severe storm analysis. Super Resolution extends the range of velocity data and provides it faster than before, also allowing for faster lead time on potential tornado detection and subsequent warnings. [18]

Dual polarization

Non-Polarimetric Radar Non-Polarimetric Radar.gif
Non-Polarimetric Radar
Polarimetric Radar Polarimetric Radar.gif
Polarimetric Radar

WSR-88D sites across the nation have been upgraded to polarimetric radar, which adds a vertical polarization to the traditional horizontally polarized radar waves, in order to more accurately discern what is reflecting the signal. This so-called dual polarization allows the radar to distinguish between rain, hail, and snow, something the horizontally polarized radars cannot accurately do. Early trials showed that rain, ice pellets, snow, hail, birds, insects, and ground clutter all have different signatures with dual polarization, which could mark a significant improvement in forecasting winter storms and severe thunderstorms. [19] The deployment of the dual polarization capability (Build 12) to NEXRAD sites began in 2010 and was completed by the summer of 2013. The radar at Vance Air Force Base in Enid, Oklahoma was the first operational WSR-88D modified to utilize dual polarization technology. The modified radar went into operation on March 3, 2011. [20]

AVSET

When the NEXRAD system was initially implemented, the radar automatically scanned all scan angles in a Volume Coverage Pattern, even if the highest scan angles were free of precipitation. As a result, in many cases when severe weather was farther from the radar site, forecasters could not provide as timely severe weather warnings as possible. The Automated Volume Scan Evaluation and Termination (AVSET) algorithm [21] helps solve this problem by immediately ending the volume scan when precipitation returns at higher scan angles drop below a set threshold (around 20 dBZ). This can often allow for more volume scans per hour, improving severe weather detection without the need for hardware upgrades [22] [23] AVSET was initially deployed in RPG build 12.3, in Fall of 2011.

SAILS and MESO-SAILS

One of the primary weaknesses of the WSR-88D radar system was the lack of frequency of base (0.5 degree) scans, especially during severe weather. Forecasters, and TV viewers at home, often had access to images that were four or five minutes old, and therefore had inaccurate information. TV viewers at home could be lulled into a false sense of security that a tornado was farther away from them than it really was, endangering residents in the storm's path. The Supplemental Adaptive Intra-Volume Low-Level Scan (SAILS) technique, deployed with Build 14 in the first half of 2014, allows operators the option to run an additional base scan during the middle of a typical volume scan. [24] With one SAILS cut active on VCP 212, base scans occur about once every two and a half minutes, with more frequent updates if AVSET terminates the volume scan early.

Multiple Elevation Scan Option for Supplemental Adaptive Intra-Volume Low-Level Scan (MESO-SAILS) is an enhancement to SAILS, which allows the radar operator to run one, two or three additional base scans during the course of a volume scan, per the operators request. [12] During June 2013, the Radar Operations Center first tested SAILSx2, which adds two additional low-level scans per volume. It was executed for approximately 4.5 hours and during the testing, an Electronics Technician observed the pedestal/antenna assembly's behavior. No excessive wear was noted. Two days later, SAILSx3 was executed, which added 3 additional low-level scans to a volume. During this 1.5 hour test of SAILSx3, a ROC Radar Hardware Engineer accompanied the ROC Electronics Technician to observe the antenna/pedestal assembly. Again, no excessive wear was noted. [25] MESO-SAILS was deployed with Build 16.1, in spring of 2016.

MRLE

Mid-Volume Rescan of Low-Level Elevations (colloquially known as M.R.L.E.) is a dynamic scanning option for the WSR-88D derived from MESO-SAILS, [26] a separate scanning option implemented in NEXRAD RPG 14.0, in the Spring of 2014. [27]

During quasi-linear convective systems (QLCS), colloquially known as squall lines, the detection of mesovortices, which generate at 4,000 to 8,000 feet above ground level, [28] is not always possible with SAILS cuts, as the base 0.5 degree scan travels below the formation of mesovortices at closer distances to the radar. MRLE consecutively scans either the two, three or four lowest scan angles during the middle of a typical volume scan, allowing more frequent surveillance of mesovortex formation during QLCS events. [29] MRLE will be deployed on a non-operational basis in RPG 18.0 in spring of 2018, with possible operational deployment with RPG 19.0, if proven useful or of importance.

Deployment was anticipated by the Radar Operations Center to commence in October 2017, along with the RPG 18.0 build, on a non-operational basis. The scanning option will only be available for use with Volume Coverage Patterns 21, 12, 212, and additionally 215. [30] If proven to be significant in terms of warning dissemination, MRLE will deploy operationally nationwide with RPG 18.0, planned for 2018.

Concept

Spin-up tornado associated with a QLCS as seen from a nearby Doppler weather radar, which often goes unseen. QLCS.png
Spin-up tornado associated with a QLCS as seen from a nearby Doppler weather radar, which often goes unseen.

The concept of MRLE derives from the need of more frequent low-level scans during quasi-linear convective systems (QLCSs). During QLCSs, it is not uncommon for brief and otherwise un-noticeable mesovortices to spawn at points along the line. [31] Due to untimely radar data and time being taken to complete the entire volume, these vortices often spawn without warning or prior notice. With MRLE, the operator has the choice between 2 and 4 low-level scans. Unlike MESO-SAILS, which scans at one angle and can only do up to 3 low-level scans per volume, MRLE scans at 4 possible angles, and can cut into a volume up to 4 times, depending on the operators choice. The angles are as followed, alongside their respective scan frequencies:

  • MRLEx2 = 0.5° and 0.9° elevations
  • MRLEx3 = 0.5°, 0.9° and 1.3° elevations
  • MRLEx4 = 0.5°, 0.9°, 1.3° and 1.8° elevations [32]

The operator can not use MESO-SAILS alongside MRLE simultaneously. If one is selected while the other is active, the NEXRAD algorithms will automatically set the other "off".

Service Life Extension Program

Started on March 13, 2013, the SLEP, or Service Life Extension Program, is an extensive effort to keep and maintain the current NEXRAD network in working order for as long as possible. These improvements include Signal Processor upgrades, Pedestal upgrades, Transmitter upgrades, and shelter upgrades. The program is anticipated to be finished by 2022, which coincides with the beginnings of a nationwide implementation of Multi-function Phased Array Radars (see below). [33]

Coverage gaps

NEXRAD coverage below 10,000 feet WSR-88DCONUSCoverage1000.jpg
NEXRAD coverage below 10,000 feet

WSR-88D has coverage gaps below 10,000 feet (or no coverage at all) in many parts of the continental United States, often for terrain or budgetary reasons, or remoteness of the area. Such notable gaps include most of Alaska; several areas of Oregon, including the central and southern coast and much of the area east of the Cascade Mountains; many portions of the Rocky Mountains; Pierre, South Dakota; portions of northern Texas; large portions of the Nebraska panhandle; the Four Corners region; the area around the Northwest Angle in Minnesota; an area near the Connecticut River in Vermont; and areas near the borders of the Oklahoma and Texas Panhandles. Notably, many of these gaps lie in tornado alley. At least one tornado has gone undetected by WSR-88D as a result of such a coverage gap – an EF1 tornado in Lovelady, Texas in April 2014. As a result of the coverage gap, initial reports of tornadic activity were treated with skepticism by the local National Weather Service forecast office. [34] [35]

Coverage gaps can also be caused during radar outages, especially in areas with little to no overlapping coverage. For example, a hardware failure on July 16, 2013 resulted in an outage and coverage gap for the Albany, New York area that lasted through early August. [36]

A coverage gap in North Carolina encouraged Senator Richard Burr to propose S. 2058, also known as the Metropolitan Weather Hazard Protection Act of 2015. The act mandates that any city with a population of 700,000 or more must have Doppler Radar coverage <6,000 feet above ground level. [37] The bill passed the Senate, but died in a House committee. [38]

It is not likely that additional WSR-88Ds will be deployed, as the production line was shut down in 1997, and the National Weather Service has an insufficient budget to restart production. [35] In 2011, a known coverage gap was filled when the Langley Hill radar in southwestern Washington was installed, using the last remaining spare. This radar opportunity was spearheaded by a public campaign led by Professor Cliff Mass at the University of Washington, and likely helped the NWS office in Portland, Oregon issue a timely warning for the Manzanita, OR EF-2 tornado in October, 2016.

In 2021, the National Weather Service office in Slidell, Louisiana announced that they would move the office's NEXRAD from the office building in Slidell west to Hammond at the end of 2022. Along with a lower elevation angle, the new location would enable lower level monitoring of storm activity in the Baton Rouge area, where the lowest sampling elevation would drop from 4000-6000 feet above the surface to 300-600 feet. [39]

Destroyed radars

The NEXRAD site located in Cayey, Puerto Rico was destroyed during the passage of Hurricane Maria through the region in September 2017. [40] In addition to a neighboring Terminal Doppler Weather Radar (TDWR) site that was rendered temporarily inoperable but ultimately survived, the Department of Defense deployed two short-range X-band radars on the island to provide radar coverage until the FAA-maintained NEXRAD site was restored. [41] In June 2018, this NEXRAD radar site was restored to fully operational condition and was reinforced with several lightning rods and secured with a stronger fiberglass dome that included using more than 3,000 bolts. [42]

On August 27, 2020, the NEXRAD radar site located in Lake Charles, Louisiana, was destroyed by Hurricane Laura as the eye of the Category 4 storm—which packed wind gusts recorded around 135 mph (217 km/h) in the city—passed over the site after it made landfall. NEXRAD radars based in Houston, Shreveport and Fort Polk were used to fill gaps in radar coverage within portions of Southwestern Louisiana until the Lake Charles site was rebuilt; the NWS Radar Operations Center also deployed a SMART-R vehicle on loan from the University of Oklahoma to provide supplemental radar data on Hurricane Delta in advance of its track into the region (nearly paralleling that of Hurricane Laura) in late October. [43] [44] [45] Operational service to the Lake Charles NEXRAD radar site was restored in January 2021, following a four-month, $1.65-million reconstruction project that included the replacement of the radome and internal equipment and repairs to the station's radome pedestal, tower, fence and equipment shelters. [46]

Future enhancements

Current NEXRAD system

The National Weather Service keeps a list of upcoming improvements to the WSR-88D system. [47]

Multi-function Phased Array Radar (MPAR)

Multi-Function Phased Array Radar during installation in Norman, Oklahoma, 2003 Par installation.jpg
Multi-Function Phased Array Radar during installation in Norman, Oklahoma, 2003

Beyond dual-polarization, the advent of phased array radar will probably be the next major improvement in severe weather detection. Its ability to rapidly scan large areas would give an enormous advantage to radar meteorologists. [48] Its additional ability to track both known and unknown aircraft in three dimensions would allow a phased array network to simultaneously replace the current Air Route Surveillance Radar network, saving the United States government billions of dollars in maintenance costs. [48] [49] The National Severe Storms Laboratory predicts that a phased array system will eventually replace the current network of WSR-88D radar transmitters. [50]

Applications

Usage

NEXRAD data is used in multiple ways. It is used by National Weather Service meteorologists and (under provisions of U.S. law) is freely available to users outside of the NWS, including researchers, media, and private citizens. The primary goal of NEXRAD data is to aid NWS meteorologists in operational forecasting. The data allows them to accurately track precipitation and anticipate its development and track. More importantly, it allows the meteorologists to track and anticipate severe weather and tornadoes. Combined with ground reports, tornado and severe thunderstorm warnings can be issued to alert the public about dangerous storms. NEXRAD data also provides information about rainfall rate and aids in hydrological forecasting. Data is provided to the public in several forms, the most basic form being graphics published to the NWS website. Data is also available in two similar, but different, raw formats. Available directly from the NWS is Level III data, consisting of reduced resolution, low-bandwidth base products as well as many derived, post-processed products; Level II data consists of only the base products, but at their original resolution. Because of the higher bandwidth costs, Level II data is not available directly from the NWS. The NWS distributes this data freely to Amazon Web Services [51] [52] and several top-tier universities, which in turn distribute the data to private organizations. [53]

Operational locations

Map all coordinates using: OpenStreetMap  
Download coordinates as: KML


See also

Notes

  1. 1 2 Timothy D. Crum; Ron L. Alberty (1993). "The WSR-88D and the WSR-88D Operational Support Facility". Bulletin of the American Meteorological Society. 74 (9): 74.9. Bibcode:1993BAMS...74.1669C. doi:10.1175/1520-0477(1993)074<1669:twatwo>2.0.co;2.
  2. 1 2 Nancy Mathis (2007). Storm Warning: The Story of a Killer Tornado . Touchstone. pp.  92–94. ISBN   978-0-7432-8053-2.
  3. Tom Banse (September 29, 2011), New Weather Radar Heralds More Accurate And Timely Storm Warnings, NPR
  4. "WSR-88D Radar, Tornado Warnings and Tornado Casualties" (PDF). National Oceanic and Atmospheric Administration. Archived from the original (PDF) on 2006-11-12.
  5. "An Overview of NEXRAD Products Available via UCAR's Unidata Program". Weather Services International. Archived from the original on 2008-04-20.
  6. "About the Radar Operations Center (ROC)". Radar Operations Center. National Oceanic and Atmospheric Administration.
  7. Prather, Michael J.; Saxion, Darcy S. "WSR-88D: Technology Evolution of Level I Data Recording" (PDF). NOAA NWS Radar Operations Center. Retrieved 14 September 2019.
  8. "NEXRAD Technical Information". www.roc.noaa.gov. Retrieved 13 April 2018.
  9. "NEXRAD Technical Information". www.roc.noaa.gov. Retrieved 13 April 2018.
  10. "Technical Implementation Notice 15–49 National Weather Service Headquarters Washington DC". Oct 22, 2015. Retrieved May 23, 2016.
  11. 1 2 3 "WSR-88D Volume Coverage Pattern (VCP) Improvement Initiatives" (PDF). National Weather Service. Oct 22, 2015. Retrieved May 23, 2016.
  12. 1 2 3 "MESO-SAILS (Multiple Elevation Scan Option for SAILS) Initial Description Document" (PDF). National Weather Service. Retrieved May 23, 2016.
  13. US Department of Commerce, NOAA. "NWS JetStream MAX - Doppler Radar Volume Coverage Patterns (VCPs)". www.weather.gov. Retrieved 2019-10-16.
  14. 1 2 "Theory and Concept of Operations for Multi-PRF Dealiasing Algorithm's VCP 112" (PDF). National Weather Service. March 19, 2019. Retrieved October 16, 2019.
  15. "Current VCP in use for each Site". www.roc.noaa.gov. Retrieved 17 August 2018.
  16. "RPG SW BUILD 10.0 – INCLUDES REPORTING FOR SW 41 RDA". Radar Operations Center. National Oceanic and Atmospheric Administration.
  17. "Build10FAQ". Radar Operations Center. National Oceanic and Atmospheric Administration. Archived from the original on 2008-07-04.
  18. "NEXRAD Product Improvement – Current Status of WSR-88D Open Radar Data Acquisition (ORDA) Program and Plans For The Future" (PDF). American Meteorological Society.
  19. "Polarimetric Radar Page". University of Oklahoma. Archived from the original on 2018-08-22. Retrieved 2003-09-09.
  20. "Technical Implementation Notice 10–22 Amended" (PDF). Radar Operations Center. National Oceanic and Atmospheric Administration. March 7, 2011.
  21. "Automated Volume Scan Evaluation and Termination (AVSET)" (PDF). National Weather Service. Retrieved March 7, 2017.
  22. Dennis Mersereau (June 18, 2014). "This One Little Programming Tweak Will Save Thousands of Lives". The Vane. Gawker Media, LLC. Archived from the original on June 19, 2014. Retrieved June 18, 2014.
  23. "Use of AVSET at RAH during the 16 November 2011 Tornado Event" (PDF). National Weather Service. Retrieved March 7, 2017.
  24. "Supplemental Adaptive Intra-Volume Low-Level Scan (SAILS)" (PDF). National Weather Service. October 30, 2012. Retrieved March 7, 2017.
  25. Chrisman, Joe (January 2014). "Multiple Elevation Scan Option for SAILS (MESO-SAILS)" (PDF). National Weather Service. Retrieved February 27, 2017.
  26. "Archived copy" (PDF). Archived from the original (PDF) on 2017-01-19. Retrieved 2017-03-07.{{cite web}}: CS1 maint: archived copy as title (link)
  27. "Archived copy" (PDF). Archived from the original (PDF) on 2017-04-27. Retrieved 2017-04-27.{{cite web}}: CS1 maint: archived copy as title (link)
  28. Atkins, N. T.; Laurent, M. St (May 2009). "Bow Echo Mesovortices. Part II: Their Genesis" (PDF). Monthly Weather Review. Retrieved February 18, 2017.
  29. "General Description Document Mid-Volume Rescan of Low-Level Elevations (MRLE)" (PDF). National Weather Service. May 12, 2016. Retrieved March 7, 2017.
  30. "New Radar Technology". Roc.noaa.gov. Retrieved 2017-04-27.
  31. "mwr2650 1514..1532" (PDF). Spc.noaa.gov. Retrieved 2017-04-27.
  32. "Archived copy" (PDF). Archived from the original (PDF) on 2017-01-25. Retrieved 2017-03-07.{{cite web}}: CS1 maint: archived copy as title (link)
  33. "Service Life Extension Program (SLEP)". www.roc.noaa.gov. Retrieved 13 April 2018.
  34. "Lovelady, Texas: A Case Study of a Tornadic Cell in a Sparse Radar Coverage Environment" (PDF). NWS Southern Region Headquarters. National Oceanic and Atmospheric Administration.
  35. 1 2 Nick Wiltgen (April 16, 2014). "The Tornado East Texas Never Saw Coming – And Why They May Not See The Next One". The Weather Channel . The Weather Company.
  36. Dennis Mersereau (July 25, 2013). "Storms flying under the radar: when radar gaps and down time turn dangerous". Washington Post .
  37. Burr, Richard (September 17, 2015). "S.2058 – To require the Secretary of Commerce to study the coverage gaps of the Next Generation Weather Radar of the National Weather Service and to develop a plan for improving radar coverage and hazardous weather detection and forecasting". United States Congress. Retrieved February 27, 2017.
  38. "All Actions S.2058 — 114th Congress (2015–2016)". United States Congress. 2 December 2016. Retrieved March 7, 2017.
  39. US Department of Commerce, NOAA. "KLIX Radar Is Moving!". www.weather.gov. Retrieved 2021-08-09.
  40. Belles, Jonathan (September 25, 2017). "Puerto Rico Radar Obliterated After It Takes a Direct Hit From Hurricane Maria". The Weather Channel. Retrieved 4 March 2018.
  41. "Federal collaboration yields radar coverage for Puerto Rico, USVI in wake of Hurricane Maria". National Oceanic and Atmospheric Administration. Retrieved 4 March 2018.
  42. Belles, Jonathan (June 18, 2018). "Puerto Rico's Radar Restored 9 Months After Hurricane Maria's Wrath". The Weather Channel. Retrieved 13 March 2019.
  43. Jonathan Erdman; Jonathan Belles (September 1, 2020). "Hurricane Laura Shredded National Weather Service Radar in Lake Charles, Louisiana". The Weather Channel. The Weather Company. Retrieved January 28, 2021.
  44. "LCH radar is going to be down a minute.... #Laura -". Brett Adair. August 27, 2020 via Twitter.
  45. Ron Brackett (October 8, 2020). "With Hurricane Delta Approaching, Loaner Radar To Cover For Lake Charles, Louisiana, Station Destroyed by Laura". The Weather Channel. The Weather Company. Retrieved January 28, 2021.
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Related Research Articles

National Weather Service U.S. forecasting agency of the National Oceanic and Atmospheric Administration

The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970.

WSR-74

WSR-74 radars were Weather Surveillance Radars designed in 1974 for the National Weather Service. They were added to the existing network of the WSR-57 model to improve forecasts and severe weather warnings. Some have been sold to other countries like Australia, Greece, and Pakistan.

WSR-57

WSR-57 radars were the USA's main weather surveillance radar for over 35 years. The National Weather Service operated a network of this model radar across the country, watching for severe weather.

Weather radar Radar used to locate and monitor meteorological conditions

Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type. Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather.

Hook echo Weather radar signature indicating tornadic circulation in a supercell thunderstorm

A hook echo is a pendant or hook-shaped weather radar signature as part of some supercell thunderstorms. It is found in the lower portions of a storm as air and precipitation flow into a mesocyclone, resulting in a curved feature of reflectivity. The echo is produced by rain, hail, or even debris being wrapped around the supercell. It is one of the classic hallmarks of tornado-producing supercells. The National Weather Service may consider the presence of a hook echo coinciding with a tornado vortex signature as sufficient to justify issuing a tornado warning.

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).

Bounded weak echo region Weather feature

The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivities aloft. This feature is associated with a strong updraft and is almost always found in the inflow region of a thunderstorm. It cannot be seen visually. The BWER has been noted on radar imagery of severe thunderstorms since 1973 and has a lightning detection system equivalent known as a lightning hole.

Aggie Doppler Radar

The Aggie Doppler Radar (ADRAD) is a Doppler weather radar located on the roof of the Eller Oceanography & Meteorology Building on the Texas A&M University campus in College Station, Texas.

ARMOR Doppler Weather Radar

ARMOR Doppler weather radar is a C-Band, Dual-Polarimetric Doppler Weather Radar, located at the Huntsville International Airport in Huntsville, Alabama. The radar is a collaborative effort between WHNT-TV and the University of Alabama in Huntsville. Live data for the radar is only available to a limited audience, such as UAH employees and NWS meteorologists. All ARMOR data is archived at the National Space Science and Technology Center located on the UAH campus.

Volumetric Imaging and Processing of Integrated Radar, known by the acronym VIPIR, is an analysis and display program for Doppler weather radar, created and sold by Baron Services. This software allows improved analysis of radar data for private users, in particular television stations, similar to the Weather Decision Support System program used by the National Weather Service.

Convective storm detection is the meteorological observation, and short-term prediction, of deep moist convection (DMC). DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus congestus to cumulonimbus, the latter producing thunderstorms associated with lightning and thunder. Those two types of clouds can produce severe weather at the surface and aloft.

GRLevelX

GRLevelX is a suite of data processing and display programs developed by Gibson Ridge Software, LLC (GRS), to view weather radar data. It went on the market in March 2005. It comes in three versions, all of which ingest raw data: GRLevel2 and GRLevel2 Analyst Edition for viewing Level II data of the National Weather Service (NWS), and GRLevel3 for viewing Level III data. All programs are capable of rendering dual polarization data.

Terminal Doppler Weather Radar

Terminal Doppler Weather Radar (TDWR) is a Doppler weather radar system with a three-dimensional "pencil beam" used primarily for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports situated in climates with great exposure to thunderstorms in the United States. As of 2011, all were in-service with 45 operational radars, some covering multiple airports in major metropolitan locations, across the United States & Puerto Rico. Several similar weather radars have also been sold to other countries such as China. Funded by the United States Federal Aviation Administration (FAA), TDWR technology was developed in the early 1990s at Lincoln Laboratory, part of the Massachusetts Institute of Technology, to assist air traffic controllers by providing real-time wind shear detection and high-resolution precipitation data.

National Weather Service Lincoln, Illinois Forecast office in central Illinois

National Weather Service Lincoln, Illinois also known as National Weather Service Central Illinois is a weather forecast office responsible for monitoring weather conditions for 35 counties in Central and Southeastern Illinois. The Central Illinois office initially consisted of two forecast offices in Peoria and Springfield until the current location in Lincoln became the sole local forecast office in 1995. Federal meteorology offices and stations in the region date back to the 19th century when the Army Signal Service began taking weather observations using weather equipment at the Springer Building in Springfield. Since that time the presence of the National Weather Service greatly increased with the installation of new weather radars, stations and forecast offices. The current office in Lincoln maintains a WSR-88D (NEXRAD) radar system, and Advanced Weather Interactive Processing System (AWIPS) that greatly improve forecasting in the region. Lincoln is in charge of weather forecasts, warnings and local statements as well as aviation weather.

National Weather Service Shreveport, Louisiana

National Weather Service - Shreveport, LA (SHV) is one of 122 weather forecast offices around the United States. It is responsible for issuing public and aviation forecasts and warning for South Central and Southwestern Arkansas, Southeastern Oklahoma, and Eastern and Northeastern Texas Counties, as well as for North Central and Northwestern Louisiana Parishes. It is co-located with a weather radar (KSHV) of the NEXRAD network and an upper air sounding facility. It controls the issuance of weather information and bulletins on a certain number of NOAA Weather Radio.

National Weather Service Norman, Oklahoma Weather Forecast Office of the National Weather Service

National Weather Service - Norman, Oklahoma is a Weather Forecast Office (WFO) of the National Weather Service based in Norman, Oklahoma, which is responsible for forecasts and the dissemination of weather warnings and advisories for central and most of western Oklahoma, and western portions of north Texas. It is located in the National Weather Center on the University of Oklahoma campus, where it acts as one of the NOAA Weather Partners, a group of close-together weather-related agencies of the National Oceanic and Atmospheric Administration. NWS Norman is currently overseen by David Andra, who serves as the Meteorologist In Charge of the office.

National Weather Service Kansas City/Pleasant Hill, Missouri

National Weather Service - Pleasant Hill/Kansas City, Missouri is a Weather Forecast Office (WFO) of the National Weather Service, which is responsible for forecasts and the dissemination of weather warnings and advisories for 37 counties in northern and western Missouri and seven counties in extreme eastern Kansas, including the Kansas City and St. Joseph metropolitan areas. Though, as the Storm Prediction Center (SPC) in Norman, Oklahoma is responsible for issuing severe thunderstorm and tornado watches, the Pleasant Hill/Kansas City WFO only composes outline and status updates for SPC-issued watches affecting any portion of its designated County Warning Area.

MESO-SAILS

Multiple Elevation Scan Option for Supplemental Adaptive Intra-Volume Low-Level Scan, is a dynamic scanning option for the WSR-88D, controllable by the operator of the radar, when in VCP mode 12 and 212, and additionally 35 and 215 with the Build 18 update scheduled for October 2017. When active, anywhere from one to three supplemental low-level scans can be added to any volume, increasing overall low-level data availability and improves general severe weather detection, as needed. When active, per the National Weather Service, low-level updates will be available "every 75 to 90 seconds".

Multifunction Phased Array Radar

Multifunction Phased Array Radar (MPAR) was an experimental Doppler radar system that utilized phased array technology. MPAR could scan at angles as high as 60 degrees in elevation, and simultaneously track meteorological phenomena, biological flyers, non-cooperative aircraft, and air traffic. From 2003 through 2016, there was one operational MPAR within the mainland United States—a repurposed AN/SPY-1A radar set loaned to NOAA by the U.S. Navy. The MPAR was decommissioned and removed in 2016.

Langley Hill Doppler radar

The Langley Hill Doppler radar (KLGX) is a National Weather Service NEXRAD Doppler weather radar station on the Pacific coast of Washington State, in the United States. Prior to its construction, Washington's Olympic Peninsula coast was the only portion of the U.S. coastline without weather radar coverage, and "virtually no radar coverage [is] available over the ocean, where the majority of western Washington's weather originates" according to a Weather Service report to the United States Congress.

References

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