The Australian Bureau of Meteorology says the tropical Pacific Ocean remains ENSO-neutral, but says chances of an El Nino developing continue to rise. It says the latest model survey shows the tropical Pacific is "very likely" to warm in the coming months, with most models showing sea surface temperatures reaching El Nino thresholds by the southern hemisphere winter (Northern Hemisphere summer).
"Observations indicate that the tropical Pacific Ocean is currently warming," states the bureau. "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."
The bureau says El Nino 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. In the U.S., an El Nino event during the growing season is associated with a better-than-normal chance of trendline to above-trendline yields.