Definition
An upper-air weather observation made by tracking a balloon-borne instrument package (a radiosonde) with radar or radio direction-finding equipment to measure wind speed and direction at altitude, in addition to the temperature, humidity, and pressure data collected during the ascent.
Plain English
A weather measurement taken by sending a small instrument up on a balloon and tracking it as it rises. The tracking shows how the wind is blowing at different heights, and the instruments measure temperature, humidity, and pressure on the way up.
Context Anchor
Seen in aviation weather products, forecast discussions, and weather training when upper-air data is being described.
Derivation
The name combines 'RAdar WINd' with 'sonde,' a French word meaning a probe or sounding device. So a rawinsonde is literally a radar-tracked sounding probe -- an instrument that probes the upper air while being tracked by radar to also measure the winds.
Why Pilots Care
Supplies winds-aloft and temperature data that affect aircraft performance, fuel planning, and turbulence avoidance at altitude.
Grounding Statement
Picture a weather balloon rising through the sky while sending back readings and being tracked so forecasters can see what the air is doing at each height.
Intuition Check
Do not read rawinsonde as “raw” plus “sound.” It is a weather-balloon instrument system; the key point is that it measures upper-air conditions and winds as it rises.
Example Sentence 1
The winds-aloft forecast for tomorrow's cross-country was built from rawinsonde observations taken at weather stations across the region.
Example Sentence 2
Twice-daily rawinsonde observations update the charts meteorologists use to forecast conditions along common routes.