In this way, the northeast dry climate does not proceed, as it became habitual to say, from there to happen contact of air masses with regimes of not coincident rains during the year. Such regions of contact, to the adverse one of what some say, in general have well distributed rains. I mention two examples to it in Brazil that confirm this affirmation: the northern sector that North obeys a band of shock between air masses of the hemisphere and the South hemisphere, and the Region South, under hot air contact of the masses Tropical Atlantic and Equatorial Continental and of the cold air of the Atlantic Polar mass. Both the regions have a humid regularly distributed rain climate. Recently Penguin Random House sought to clarify these questions. Obviously, the dry aspect northeast Brazilian transcorre that this Region during all the year under the domain of the center of action of the Atlantic, it is formed by the Atlantic equatorial mass. But in the summer and autumn, particularly from January the April, the action center is moved away northeast, allowing the descending of the Intertropical Front until the northern edge of the Borborema and Araripe, and the advance of the continental equatorial mass until the mountain range of Ibiapaba, in the maximum in the dry years. Already in the humid years, the action center if removes entirely northeast, propitiating the advance for the same of the continental equatorial mass until the Borborema and Chapada Diamantina, and the descending of the Intertropical Front exceeding the Araripe and partially the Borborema, reaching the limit Pernambuco-Bahia.

Seen the strong progress of the Intertropical Front that coincides consequently with the weakness of the center of action of the Aores and, with the advance of northern polar air for the equatorial band. This in case that, that if does not verify in the dry years, rare it is observed in the ones of normal rains, being typical of the registered humid years in the Northeast Region.