Under the influence of Madden–Julian oscillations, heavy showers (more than 100 mm) can be expected over the island during the next few days, the Met Dept. said in its weather forecast issued at 12 noon today. In addition, the Dept. said that a low pressure area located to the South-east of Sri Lanka will move towards Sri Lankan area and hence showery weather in the Eastern half of the country will further increase after tomorrow (07). The Madden-Julian Oscillation (MJO) is a tropical weather system that lasts about 1 to 2 months. It is one of the few aspects of the weather that can be skilfully predicted beyond about 2 weeks into the future. It was discovered in 1971 by Roland Madden and Paul Julian of the American National Center for Atmospheric Research (NCAR). It is a large-scale coupling between atmospheric circulation and tropical deep convection. The Madden–Julian oscillation is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian and Pacific Ocean.