Weekly Tropical Climate Note

Issued on Tuesday 18 June 2013 2013

Madden-Julian Oscillation intensifies over the Maritime Continent

Over the past week, the Madden-Julian Oscillation (MJO) has intensified, with a pulse of enhanced convection currently located north of the Maritime Continent. The MJO is forecast to move steadily eastwards into the western Pacific and begin to weaken. Typically, an MJO moving into the Pacific Ocean at this time of year can mediate easterly winds resulting in cooler than average minimum temperatures for much of northern Qld and the northeast Top End in the coming fortnight.

With the MJO in its current location there is an increased risk of tropical cyclone formation in the northwest Pacific. This year has seen a particularly late start to the tropical cyclone season. As the MJO moves into the western hemisphere later this month, the chance of tropical cyclone formation will decrease. A tropical depression is currently present off the east Philippine coast and is expected to develop further as it moves north.

See the Bureau's MJO Monitoring for more information on location and tracking of the MJO.

A negative IOD likely for the dry season

Over the past week sea surface temperatures in the tropical Indian Ocean have remained warmer than normal in the east, and have cooled further in the west, consistent with model forecasts of a negative Indian Ocean Dipole (IOD) later this dry season. These conditions will generally enhance rainfall over much of southern and central Australia for the next three months (see the Seasonal Rainfall Outlook ). The El Niño Southern Oscillation index remains neutral with the latest 30 day SOI value at +12.0. Most climate models indicate a neutral ENSO event for 2013, though a small chance of a La Niña developing still exists. Neutral ENSO neither significantly strengthens nor weakens the southeast trade winds which affect northern Australia in the dry season.

See the Bureau's ENSO Wrap-Up which includes a compilation of ENSO computer model predictions.

Next update expected by 25 June 2013| Product Code IDCKGEWOOO

For more information please contact climate.nt@bom.gov.au