Econintersect Weather and Climate Forecast Update
Written by Sig Silber
The odds of an El Nino continue to increase but it is not at all clear if this is going to be a powerful El Nino or simply a break from ENSO neutral conditions. That makes a huge difference in regards to impacts on weather starting this summer.
The short term 6 – 14 day forecast has transitioned to Spring conditions and the prior confusing forecast which called for continued intrusion of cold air from the north is no longer in the forecast.
According to Australia’s Bureau of Meteorology:
“Tropical Pacific continues to warm; El Niño likely in 2014
Issued on Tuesday 6 May 2014
The tropical Pacific Ocean has warmed steadily in recent months, with large warm anomalies in the ocean sub-surface (5-day values up to +6 °C) and increasingly warm sea surface temperatures. Climate models surveyed by the Bureau suggest El Niño development is possible as early as July. These factors indicate that while El Niño in 2014 cannot be guaranteed, the likelihood of an event developing remains at least 70% and we are at El Niño ALERT level.
For El Niño to be established and maintained, coupling needs to occur between the tropical Pacific atmosphere and ocean, evident by further and persistent weakening of the trade winds and a consistent increase in cloudiness near the Date Line. These atmospheric characteristics of El Niño are forecast to become evident over the coming months.
El Niño impacts climate across much of the world, including below average rainfall in the western Pacific and Indonesian regions, and increased rainfall in the central and eastern Pacific. For Australia, El Niño is usually associated with below average rainfall over southern and eastern inland Australia, with about two thirds of El Niño events since 1900 resulting in major drought over large parts of the continent.
The Indian Ocean Dipole (IOD) is currently in a neutral state. Model outlooks suggest the IOD is likely to remain neutral through late autumn and early winter, with two of the five models surveyed suggesting a positive IOD may develop by early spring. Positive IOD events often coincide with El Niño and are typically associated with large parts of southern and central Australia experiencing lower rainfall than usual.”
Notice this model forecast barely puts the Pacific into El Nino Conditions. That conflicts a bit with the NOAA forecast which is a bit more robust. El Nino is likely but it is certainly not a done deal by any means. This become important in terms of impacts as a minor El Nino has correspondingly minor impacts.