Weekly Tropical Climate Note
Issued on Tuesday 4 March 2014
Madden-Julian Oscillation progresses across the Pacific
A break in the North Australian Monsoon continued over the past week, while active tropical convection has brought heavy rainfall and floods to some south Pacific Islands. Tropical cyclone Kofi passed near Fiji and Tonga over the weekend bringing gale force winds and heavy rains.
This week, the western equatorial Pacific Ocean features a pair of lows—slow moving tropical cyclone Faxia in the northern hemisphere and a tropical low south of the Solomon Islands that is forecast to move toward Australia's Cape York Peninsula in the coming days, potentially reaching tropical cyclone strength prior to crossing the coast.
The Madden-Julian Oscillation (MJO) remains over the western Pacific Ocean and is moving into the western hemisphere. When the MJO is over the western hemisphere at this time of year it usually increases the risk of tropical cyclone formation in the South Pacific, and supresses tropical convection activity across the tropical Indian Ocean, the Maritime Continent and northern Australia. The MJO is forecast to continue eastward, but forecast models disagree about its strength. Some models predict a weakening of the signal within the next 10 to 14 days, while others maintain its strength. When the MJO weakens it has less influence on tropical weather.
See the Bureau's MJO Monitoring for more information on location and tracking of the MJO.
ENSO state: neutral, warming expected
The El Niño–Southern Oscillation (ENSO) remains neutral. The 30-day Southern Oscillation Index (SOI) value to 2 March is -2.0.The latest NINO3.4 sea surface temperature anomaly is -0.3 °C.
The tropical Pacific Ocean is likely to warm in the coming months. Climate models suggest Pacific Ocean temperatures may approach or exceed El Niño thresholds in the austral winter. However, model outlooks at this time of the year have lower skill than outlooks made at other times, and hence should be used cautiously.
El Niño events usually, but not always, coincide with drier than normal conditions across eastern and northern Australia and an eastward shift in tropical cyclone activity in the South Pacific.
See the Bureau's ENSO Wrap-Up which includes a compilation of computer model predictions of ENSO indices.
Next update expected by 11 March 2014| Product Code IDCKGEWOOO
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