Next Generation Weather Radar (NEXRAD) (2024)

Base Reflectivity (N0R, N1R, N2R, N3R/19 and N0Z/20)

A display of echo intensity measured in decibels relative to Z (dBZ). Scientists use these products to detect precipitation, evaluate storm structure, locate boundaries, and determine hail potential. Four low elevationangles are available, with specific elevation angles depending on the scanning mode of the Radar. Sixteen possible data levels are also available.

Digital Base Reflectivity (NXQ, NYQ, NZQ, N0Q, NAQ, N1Q, NBQ, N2Q, N3Q/94)

The same as N*R products defined above, except data values are actual reflectivity values instead of categories, data extends to further range, and additional elevations are available. Products from elevation angles at or below 3.5 degrees are available, and select sites may also scan at an additional low elevation angle, as low as -0.2 degrees. Specific elevation angles depend on the site and scanning mode of the Radar.

Base Velocity (N0W/25, N0V, N1V, N2V, N3V/27)

A measure of the radial component of the wind either toward the radar (negative values) or away from the radar (positive values). Cool colors (green) represent negative values and warm colors (red) represent positive values. Scientists use these products to estimate wind speed and direction, locate boundaries, locate severe weather signatures, and identify suspected areas of turbulence.

Digital Base Velocity (NXU, NYU, NZU, N0U, NAU, N1U, NBU, N2U, N3U/99)

The same as N*V products defined above, except data values are actual velocity values instead of categories, data extends to further range, and additional elevations are available.

Storm Relative Velocity (N0S, N1S, N2S, N3S/56)

A stationary storm image that is generated by removing storm motion measurements from the wind field. Color indices are the same as base velocity. Comparing the storm relative motion image with base velocity image helps identify the rotating storm.

Base Spectrum Width (NSP/28, NSW/30)

A measure of velocity dispersion within the radar sample volume. This product's primary use is to estimate turbulence associated with mesocyclones and boundaries.

Composite Reflectivity (NCO/36, NCR/37, NCZ/38)

Composite Reflectivity displays the maximum reflectivity from all scanned heights above the ground during the volume scan. These products reveal the highest reflectivities in all echoes, examine storm structure features, and determine the intensity of storms.

Low/Mid/High Layer Composite Reflectivity (NLL/65, NML/66, NHL/90, NLA/67)

Low/Mid/High Layer Composite Reflectivity is a display of maximum reflectivity for three different height ranges within the volume scan. Use this product to reveal the highest reflectivities in all echoes, examine storm structure features, and determine the intensity of storms. The NLA/67 product is similar to NLL/65, but edited to remove contamination from anomalous propagation.

Vertically Integrated Liquid (NVL/57, DVL/134)

This product color codes and plots the water content of a 2.2 x 2.2 nautical mile (nm) column of air. It is an effective hail indicator that can be used to locate most significant storms and identify areas of heavy rainfall. The DVL version of the product provides a higher spatial resolution and enhanced processing.

Echo Tops (NET/41, EET/135)

This product generates a color coded image that shows the height of an echo top. Scientists use this product to quickly estimate the most intense convection and higher echo tops, as an aid to identify storm structure features, and for pilot briefing purposes. The EET version of the product provided a higher spatial resolution, and enhanced processing, including identification of weather that is higher than the radar can scan.

VAD Wind Profile (NVW/48)

This product plots wind barbs on a height staff in 1,000-ft. increments. The current (far right) and up to 10 previous plots may be displayed simultaneously. This product is an excellent tool for meteorologists in weather forecasting, severe weather, and aviation.

Differential Reflectivity (ZDR) (NXX, NYX, NZX, N0X, NAX, N1X, NBX, N2X, N3X/159) (Dual-Pol. only)

Differential Reflectivity values are measurements related to the returned energy difference between the vertically and horizontally polarized radar pulses. Large positive values indicate wider targets. Values near zero indicate the targets are generally spherical. Negative values indicate targets are larger in the vertical than in the horizontal. Products from elevation angles at or below 3.5 degrees are available, and select sites may also scan at an additional low elevation angle, as low as -0.2 degrees.

Correlation Coefficient (CC) (NXC, NYC, NZC, N0C, NAC, N1C, NBC, N2C, N3C/161) (Dual-Pol. only)

Correlation Coefficient values are measurements related to the similarity between the behaviors of the horizontally and vertically polarized pulses and how they behave within a pulse volume. Values between 0.95 and 1.0 indicate near uniformity in pulse behavior. Meteorological targets with complex shapes, or with a large degree of variety, will generally have values between 0.85 and 0.95. Biological targets, anthropogenic targets, and ground clutter tend to cause very different behaviors between the pulses, resulting in values less than 0.9 (and often less than 0.7).

Specific Differential Phase (KDP) (NXK, NYK, NZK, N0K, NAK, N1K, NAB, N2K, N3K/163) (Dual-Pol. only)

Specific Differential Phase measures the difference between the horizontally and vertically polarized pulse phase changes as they travel through the atmosphere. KDP can be used to detect areas of heavy rain, and high KDP values correlate with large raindrops (and in some cases, melting hail).

Hydrometeor Classification (HC) (NXH, NYH, NZH, N0H, NAH, N1H, NBH, N2H, N3H/165 (Dual-Pol. only)

Hydrometeor Classification is a computer algorithm output that tries to classify targets in the radar volume. The product compares targets to a set of predefined categories, and displays a list of the most likely echo sources.

Melting Layer (ML) (NXM, NYM, NZM, N0M, NAM, N1M, NBM, N2M, N3M/166) (Dual-Pol. only)

Melting Layer is a computer algorithm output that determines the atmospheric melting point for frozen precipitation. This product provides information about the state (frozen, melting, or fully liquid) of precipitation at different altitudes in a particular area. This product is generated for each elevation angle that the radar scans and can be particularly useful for tracking icing conditions above the surface. It may have problems when surface temperatures are below freezing, in mountainous locations, or when data needed for the algorithm is limited. When radar echoes are insufficient for the algorithm to work properly, it will default to the manually entered or model generated freezing level data.

Hybrid Hydrometeor Classification (HHC/177) (Dual-Pol. only)

The Hybrid Hydrometeor Classification is obtained from the best/lowest available scan at each location. This product serves as input to the dual-polarization precipitation estimation products.

Next Generation Weather Radar (NEXRAD) (2024)

FAQs

Can NEXRAD penetrate weather? ›

The Owner's Manual for the GPS device specifically states that NEXRAD weather data should be used for “long-range planning purposes only,” and not to “penetrate hazardous weather,” as the “NEXRAD data is not real time.” The NTSB meteorologist determined that the NEXRAD mosaic images were up to eight minutes, 22 seconds ...

How long does it normally take for radar images to get sent from a NEXRAD site? ›

Because the Nexrad scans vertically and horizontally, looking in great detail, it takes five to six minutes to complete a 360 degree scan. That means it can be six minutes since the radar scanned the piece of air you're flying in right now.

How many NEXRAD radars are there in the US? ›

The Next Generation Weather Radar (NEXRAD) system is a network of 160 high-resolution S-band Doppler weather radars jointly operated by the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the U.S. Air Force.

How delayed is NEXRAD? ›

Abstract. Data-linked Next Generation Weather Radar (NEXRAD) images can be delayed up to 20 min in the co*ckpit.

What are the limitations of NEXRAD radar? ›

This has created a revolution in the way pilots approach thunderstorm avoidance, but one of the biggest limitations of NEXRAD is also the biggest lure into bad weather—a time delay. NEXRAD radars take multiple vertical and horizontal scans, which are then collated with other stations prior to broadcast.

How accurate is NEXRAD? ›

The study con- cluded that NEXRAD precipitation estimates were 5–10% less than rain gauge estimates overall for the three-year study period, and further that NEXRAD tended to underestimate rainfall for storm events.

Can NEXRAD detect clouds? ›

There seems to be a mixing of terms---Satellites generally show clouds; Radar/Nexrad generally shows precip and not clouds so you have to be using/comparing images of one kind, radar to radar and satellite to satellite not one to the other.

Which weather radar is the most accurate? ›

The WSR-88D is one of the most powerful and advanced Weather Surveillance Doppler Radar in the world. Since first being built and tested in 1988, it has been installed and used operationally at over 160 locations across the United States, including Alaska and Hawaii.

What is the difference between NEXRAD and TDWR? ›

The TDWR radar stations are maintained and operated by the Federal Aviation Administration. Both radar's are pulsed Doppler types that measure reflectivity out to 460 km, and radial velocity and spectrum width out to 300 km for NEXRAD and 90 km for TDWR.

Are NEXRAD and Doppler the same? ›

NEXRAD systems are Doppler weather radars that detect and produce over 100 different long-range and high-altitude weather observations and products, including areas of precipitation, winds, and thunderstorms.

What frequency is the NEXRAD radar? ›

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.

How long does NEXRAD take to update? ›

With FIS-B, NEXRAD data should be updated every 10 minutes or so. The data link to your aircraft is really slow, so it could take quite a few minutes to upload it all.

What is NEXRAD Level 3 radar? ›

NEXRAD Level 3 products are used to remotely detect atmospheric features, such as precipitation, precipitation-type, storms, turbulence and wind, for operational forecasting and data research analysis.

What is NEXRAD Level 2 radar? ›

Level II data are the digital radial base data (Reflectivity, Mean Radial Velocity, and Spectrum Width) and Dual Polarization variables (Differential Reflectivity, Correlation Coefficient, and Differential Phase) output from the signal processor in the Radar Data Acquisition unit.

Can radars penetrate rain? ›

TDWR attenuation problems

This attenuation means that the radar cannot "see" very far through heavy rain.

Is radar blocked by rain? ›

Yes. Rain generally affects the range of the radar, not the accuracy.

Does rain affect radar guns? ›

Yes, police can use radar in the rain. However, certain factors can affect the accuracy and efficiency of radar systems during bad weather. Our findings show that, while radar systems are robust, heavy rain can reduce their range.

Can marine radar be used for weather? ›

A marine radar device acts as a major navigation aid for boaters. It helps in detecting boats, birds, landmasses, and weather systems - even if the visibility is less than usual.

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