Mainly this is just new terminology for me, never heard of it before. Does this happen every year, is it different this year, I don't know. I ran into the term and the map on a message board in a weather conversation. It looks ominous for the west coast of Mexico but this could be a yearly occurrence? Will it move next week? Sorry but you'll have to Google the subject if you want to learn more about this phenomenon
The Monsoon Trough is a favored place for tropical cyclones to develop, while this generally does not occur with the ITCZ (Intertropical Convergence Zone) due to its proximity to the equator where the Coriolis effect is zero, and thus rotary motion around a low-pressure center cannot be supported. Thus people should be aware that a tropical depression or tropical storm could form in the vicinity of the Monsoon trough.