Which present weather group indicates a tornado or waterspout?

The presence of a tornado or waterspout is indicated by the symbol for funnel clouds, which is represented as "+FC." This shorthand notation is included in the weather observation reports to signify significant weather phenomena. The "+FC" code stands for "funnel clouds," which encompasses both tornadoes and waterspouts depending on their location relative to land or water.

In the context of severe weather reporting, the indication of any funnel cloud activity is crucial for aviation operations and safety. Observers note these conditions to warn pilots and ground personnel of potential dangerous situations. Hence, the inclusion of "+FC" in the options correctly correlates with the phenomenon of tornadoes and waterspouts, highlighting the severe nature of the weather that pilots and meteorologists need to monitor closely.

While the other choices may represent various weather phenomena and conditions, they do not specifically indicate the occurrence of tornadoes or waterspouts, making "+FC" the most relevant and specific indicator for those particular weather events.