El Niño
I don’t think that any of the FAA books cover El Niños, but as flyers, we should be aware of their impact. The drought in California from 2012-2016 was primarily caused by the weather pattern associated with the lack of an El Niño, a La Niña, as well as the effects of global climate change. In 2017, the west coast has been hit with many atmospheric rivers caused by lingering effects of an El Niño.
The NASA Earth Observatory has a long article explaining how they form and the worldwide effects on weather.