Vanlig radar oppdager nedbør ved å se hvor sterke radiobølger som returnerer. Dopplerradar gir muligheten til å måle bevegelse. Den registrerer frekvensforskyvningen i det returnerte signalet forårsaket av regndråper eller snøflak i bevegelse, og avslører om nedbøren nærmer seg eller avtar.

This velocity information shows wind patterns inside storms. Meteorologists can identify rotation that may produce tornadoes, detect strong outflow boundaries, and estimate rainfall rates more accurately. Dual-polarization upgrades further improve the discrimination between rain, hail, and non-meteorological targets.

National networks of Doppler radars provide continuous coverage over large areas. Data appear on public websites and television broadcasts within minutes. The technology has sharply reduced the average warning time for severe thunderstorms and tornadoes.

Research radars continue to refine the technique for even finer-scale measurements.