What does it mean if there is lightning under the cloud in the weather forecast of Apple's mobile phone?

Iphone weather map means: light rain: only one drop of water falls on the cloud; Moderate rain: two drops of water fall from the clouds; Heavy rain: three drops of water fall from the clouds; Heavy rain: four drops of water fall from the clouds; Shower: an inverted triangle with a light rain spot on it.

1. Weather symbol: a special symbol representing various weather phenomena, clouds and sky conditions. Includes weather phenomenon symbols for observation and recording and weather graphic symbols for media communication.

2. When observing a certain weather phenomenon, meteorological observers should record the corresponding symbols in the "Weather Phenomenon" column of the observation record book of the day, except for a few phenomena, and also record the starting and ending time. Based on these symbols, combined with the intensity, coexistence and some characteristics of weather phenomena, a group of symbols that can be filled in weather maps are called cartographic symbols.