How does bad weather, such as heavy rain, affect ARPA's performance?

Heavy rain can significantly affect the performance of an Automatic Radar Plotting Aid (ARPA) system, particularly in the realm of small target detection. The presence of heavy precipitation can create a cluttered radar display, making it difficult for the ARPA to differentiate between actual targets and the noise generated by the rain. This sensory overload can obscure smaller vessels or other objects, reducing the system's ability to track these targets accurately.

In scenarios of heavy weather, radar waves may scatter or be absorbed by the rain, leading to decreased return signals for smaller targets. As a result, ARPA systems might miss detecting these targets altogether, thereby compromising situational awareness and navigational safety. Thus, the impact of heavy rain directly correlates to an increased likelihood of lost detection of small targets, making the selected answer pertinent in the context of ARPA performance under adverse weather conditions.