What indicates a "severe thunderstorm" on a radar image?

The indication of a "severe thunderstorm" on a radar image is associated with echoes of high intensity, often displayed in red areas, alongside observable rotation patterns. High-intensity echoes suggest the presence of heavy precipitation, which is common in severe thunderstorms. The red areas typically represent areas of the radar reflecting strong signals, indicating more significant precipitation rates and potentially severe weather conditions, including strong winds and hail.

In addition to the high-intensity echoes, rotation patterns on the radar signify the development of rotating storm systems, which can lead to the formation of tornadoes. This combination of characteristics—both the intensity of the echoes and the presence of rotation—has a strong correlation with severe weather phenomena, thus helping meteorologists identify and issue warnings for severe thunderstorms.