Definition
The WSR-88D NEXRAD is the network of high-power, ground-based Doppler weather radars operated jointly by the National Weather Service, the FAA, and the Department of Defense. It detects precipitation, measures its intensity, and tracks the motion of weather systems by sensing the frequency shift of radar energy reflected from raindrops, snow, hail, and other particles in the atmosphere. Its products — including reflectivity, precipitation intensity, storm motion, and severe weather signatures — are distributed to pilots through Flight Service, ATC, and aviation weather products such as the Aviation Weather Center.
Plain English
A nationwide system of powerful ground radars that watch the weather. They show where rain, snow, and storms are, how heavy the precipitation is, and which way the weather is moving. The data ends up in the weather briefings and radar images pilots use before and during flight.
Context Anchor
Seen in aviation weather discussions, radar observation sections, preflight weather briefings, and weather displays that show NEXRAD radar images.
Derivation
WSR-88D stands for Weather Surveillance Radar, deployed in 1988, with Doppler capability — meaning it can detect motion, not just the presence of precipitation. NEXRAD simply means 'Next Generation Radar,' the name given to the program that replaced older 1950s and 1970s weather radars. Knowing the 'D' stands for Doppler explains why this radar can show storm motion and rotation, not just rainfall location.
Why Pilots Care
Supplies real-time storm location and intensity data that pilots use to avoid thunderstorms, turbulence, and areas of heavy precipitation.
Grounding Statement
Picture large radar antennas on the ground sweeping the sky and building a weather picture from the energy that bounces back from precipitation.
Intuition Check
NEXRAD does not mean the pilot is seeing every hazard instantly. It is a processed radar picture, and the image may be delayed from the actual weather outside.
Example Sentence 1
During preflight planning, the pilot reviewed the WSR-88D NEXRAD image and saw a line of heavy precipitation moving east across the proposed route.
Example Sentence 2
NEXRAD returns from the WSR-88D network are displayed on the tablet to show precipitation intensity around the destination airport.