Increased chance of El Niño in 2014
By Bureau of Meteorology (ENSO Wrap-Up, 25 March 2014)
While the tropical Pacific Ocean remains El Niño–Southern Oscillation (ENSO) neutral, the chance of an El Niño occurring in 2014 has increased. The latest climate model survey by the Bureau shows that the tropical Pacific is likely to warm in the coming months, with most models showing sea surface temperatures reaching El Niño thresholds during the southern hemisphere winter.
Observations indicate that the tropical Pacific Ocean is currently warming. Following two strong westerly wind bursts since the start of the year, waters below the surface of the tropical Pacific have warmed significantly over the past two months. This has led to some warming at the surface, with further warming expected in the coming weeks. The Southern Oscillation Index (SOI) has dropped to –13—the lowest 30-day value since March 2010—but would need to remain firmly negative for several weeks to indicate the atmosphere and ocean are reinforcing each other.
El Niño is often, but not always, associated with below normal rainfall across large parts of southern and inland eastern Australia during the second half of the year. Daytime temperatures also tend to be above normal over southern Australia.
The Indian Ocean Dipole (IOD) is typically too weak to have a significant influence on the Australian climate from December to April. Current model outlooks indicate a neutral IOD through late autumn and early winter.