What aspect of hail does weather radar struggle to identify?

Weather radar is particularly effective at detecting precipitation, including hail, by measuring the intensity of the return signal from raindrops or ice particles in the atmosphere. However, one aspect that challenges radar technology is the penetrable surface of the hail. This refers to the structural characteristics of hailstones, particularly their density and internal composition, which affect how radar waves interact with them.

Radar systems primarily gauge the size and intensity of precipitation, but they do not effectively determine the properties of the surface they are encountering. For instance, while radar can suggest that precipitation is occurring, it may struggle to assess whether the surface (such as a hailstone) is solid or porous, which can impact the accuracy of the size measurement. This limitation stems from the inherent characteristics of radar waves, which may scatter differently based on the composition and density of the precipitation they are scanning, thus making it difficult to accurately assess the substance a hailstone is made of.

In contrast, weather radar can generally estimate the size and descent speed of hail, as these factors are more directly related to the precipitation's intensity and movement, making them more identifiable in the radar data. Hence, the aspect of hail that weather radar has difficulty identifying is indeed related to its penetrable surface.