Parts of the Brazilian highlands extend upto the northern coast. The winds blowing from the Southern Atlantic Ocean in the southeast and the northeast direction are obstructed by the Brazilian Highlands.
These winds move upward along with the slopes of the Brazilian Highlands. At higher altitude, the condensation process takes place and windward side of Brazilian Highlands receives more rain.
When these winds cross the top of Brazilian Highlands, go to other side of the mountain, these winds are dry. As its effect, the leeward side of the Brazilian Highlands gets less rainfall.
Therefore, the northeastern part of Brazilian Highlands receives very less rainfall. This region is called ‘Drought Quadrilateral’