Base Reflectivity is one of the basic quantities that a Doppler radar (like NEXRAD) measures. The other base products NEXRAD produces are Base Velocity and Spectrum Width (which is not available via NIDS). Base Reflectivity basically corresponds to the amount of radiation that is scattered or reflected back to the radar by whatever targets are located in the radar beam at a given location. These targets can be hydrometeors (snow, rain drops, hail, cloud drops or ice particles) or other targets (dust, smoke, birds, airplanes, insects). The colors on the Base Reflectivity product correspond to the intensity of the radiation that was received by the radar antenna from a given location.

Base Reflectivity Level 1

Base Reflectivity 250 Miles

Composite Reflectivity (250 Miles) is the maximum base reflectivity value that occurs in a given vertical column in the radar umbrella. NEXRAD scans in several pre-defined "volume coverage patterns (VCPs), where the radar makes a 360-degree horizontal sweep with the radar antenna tilted at a given angle above the horizontal, then changes the elevation angle, and completes another 360-degree sweep, and so on. Composite reflectivity gives a plan view of the most intense portions of thunderstorms, and can be compared with Base Reflectivity to help determine the 3-D structure of a thunderstorm.

Storm total precipitation accumulation

Storm total 1 Hour precipitation accumulation

Storm total 3 Hour precipitation accumulation