Weekly Tropical Climate Note

Issued 24 March 2015

Madden-Julian Oscillation to weaken

An exceptionally strong burst in Madden-Julian Oscillation (MJO) activity is currently in the western hemisphere. It is likely to have contributed to the increase in tropical activity observed in the central Pacific Ocean this past week.

Climate models indicate the MJO will weaken as it moves steadily eastwards over Africa towards the Indian Ocean during the coming week. Generally when the MJO traveles over Africa, tropical weather becomes supressed over the tropical Indian Ocean, northern Australia and tropical Asia. However, ex-tropical cyclone Nathan and an active monsoon trough to the north of Australia are likely to bring storms to Australia's northern coastal regions this week.

See the Bureau's MJO Monitoring for more information.

El Niño in 2015 remains possible

The central tropical Pacific Ocean remains warmer than average and conducive for the development of El Niño in 2015. Persistent anomalous westerly wind over the equator in the western Pacific Ocean is likely to lead to further sea surface temperature warming. All international climate models monitored by the Bureau predict the tropical Pacific Ocean will reach or exceed El Niño thresholds by mid-year. However, the accuracy of model forecasts at this time is lower than for forecasts made at other times.

The latest weekly NINO3.4 sea surface temperature anomaly is +0.6 °C, the latest 30-day value of the SOI (22 March) is −11. Both indices show a tendency towards El Niño conditions.

See the Bureau of Meteorology's ENSO Wrap-Up for official El Niño information.

Next update expected by 31 March 2015 | Product Code IDCKGEW000

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