One of the most important instruments meteorologists use in tracking a storm, Doppler weather radar is used to identify the location of precipitation.
Doppler radar reflectivity is the amount of transmitted power returned to the radar antenna after the signal is reflected by precipitation or other obstructions. This reflected radar signal is measured in dBZ, which are decibels of "Z" or energy. Shown here is the base reflectivity, which measures reflectivity from the radar antenna's lowest tilt angle (0.5° above the horizon). A value of 20 dBZ is typically the point at which light rain begins while values in the range of 60-65 dBZ could be an indication of hail or other severe weather.