Definition
An upper-air weather observation made by tracking a balloon-borne instrument package with radar to measure wind speed and direction at various altitudes, in addition to the temperature, humidity, and pressure data transmitted by the instrument itself.
Plain English
A weather measurement taken by sending up a balloon carrying instruments and then following it with radar. The instruments report temperature, humidity, and pressure on the way up, and the radar tracking shows how the winds are blowing at each altitude.
Context Anchor
Seen in weather and flight-planning discussions involving upper-air data, winds aloft, and forecast preparation.
Derivation
Combines 'radar' (radio detection and ranging) with 'sonde,' from the French word for a sounding probe — an instrument lowered or sent out to measure something. Together it means using radar to track a probing instrument through the atmosphere.
Why Pilots Care
Winds aloft forecasts and upper-air charts that pilots rely on for flight planning are built largely from these observations. Knowing where the data comes from helps pilots understand both its value and its limitations.
Grounding Statement
Picture a weather balloon climbing through the sky while radar follows it and reports what the air is doing at each height.
Intuition Check
A radarsonde observation is not a radar picture of rain or storms. It is a balloon-based weather measurement tracked by radar.
Example Sentence 1
Forecasters use radarsonde observations from stations across the country to build the winds aloft charts pilots check before a cross-country flight.
Example Sentence 2
Updated radarsonde observations helped adjust the expected winds aloft for the morning departure.