El Niño event almost certain: BOM
Posted by feww on July 1, 2009
El Niño event likely, says Australia’s Bureau of Meteorology
More evidence of a developing El Niño event has emerged during the past fortnight, and computer forecasts show there’s very little chance of the development stalling or reversing. —BOM
Equatorial sea-surface temperatures are currently more than 1°C above normal in the eastern Pacific, while the Southern Oscillation Index (SOI) remains below zero at around −2, says BOM.
A sustained negative SOI is often associated with El Nino conditions.
BOM hopes to provide a clear picture of the situation in the Pacific by next week when their final June data are analyzed.
El Niño events are usually (but not always) associated with below normal rainfall in the second half of the year across large parts of southern and inland eastern Australia.
Another adverse sign for southeastern Australian rainfall is the recent trend to positive values in the Indian Ocean Dipole (IOD), as measured by the Dipole Mode Index (DMI).
The next BOM update is available on July 8, 2009.
Images from Tropical Atmospheric Ocean project: NOAA
Summary of BOM Weekly Update:
- The Pacific Ocean sea surface is currently significantly warmer than the long-term average across most of the tropical Pacific, especially central to eastern areas.
- A large amount of the sub-surface water of the tropical Pacific is also warmer than the long-term average, particularly in the east.
- The latest 30-day SOI value is −2, while the monthly value for May was −5.
- Trade winds remain weaker than normal across the central equatorial Pacific.
- Cloudiness near the date-line is near-normal, and is yet to show a consistent trend towards El Niño conditions.
- All international climate models predict the tropical Pacific to continue to warm and to be above El Niño thresholds throughout most of the second half of 2009.
“Australia is the world’s fourth-largest wheat exporter and its grain production is still recovering from the worst drought in more than 100 years that reduced the 2006/07 crop to just 10.6 million tonnes and the 2007/08 crop to 13.0 million tonnes.” Reuters reported.
FEWW Moderators estimate that a new episode of El Niño, which would have devastating impact globally, could cause up to $500 billion in damages.
See also comments section for latest updates.