Weather Tidbits: The Madden Julian Oscillation

This edition of Weather Tidbits will be discussing the Madden Julian Oscillation, also known as the MJO. The MJO is an eastward spread of large regions of enhanced and suppressed rainfall within the tropical latitudes. It progresses eastward through a series of 8 phases. Each phase features different regions of enhanced and suppressed tropical rainfall associated with rising and sinking air respectively. Rising air will have associated sinking air to achieve balance in the atmosphere. Each cycle with all phases lasts anywhere from 30 to 60 days before repeating the next cycle.

The MJO can have implications on tropical activity in the Atlantic. In phases 2 through 6, sinking air in the Atlantic will generally suppress tropical activity. Phases 7 through 1 will enhance tropical activity because of large scale rising air.