Economic Collapse

[basserdan]

El Niño ALERT; likelihood of El Niño in 2019 increases

ENSO Wrap-Up
Issued 19 March 2019
Next issue 2 April 2019

The El Niño–Southern Oscillation (ENSO) is currently neutral. The Bureau's ENSO Outlook* has moved to El Niño ALERT.

This means the chance of El Niño developing in 2019 has increased to approximately 70%, around triple the normal likelihood.

Tropical Pacific sea surface temperatures have touched on El Niño thresholds for the past three weeks, while waters below the surface are also slightly warmer than average. Signs of El Niño in the atmosphere are less clear. While values of the Southern Oscillation Index (SOI) are currently within El Niño bounds, the index is likely to weaken in the coming days. Large swings in the SOI are not uncommon during the southern hemisphere monsoon season. Additionally, trade winds have been closer to normal over the past fortnight after a period of weakened trades in the western tropical Pacific.

Most international climate models suggest sea surface temperatures in the central tropical Pacific Ocean are likely to remain at El Niño levels into winter. Sustained warmer than average ocean waters would increase the likelihood of coupling between the atmosphere and ocean, which would typically cause changes in Australian and global weather patterns. However, current outlooks have less skill for the period beyond May, and therefore predictions for the latter months should be viewed with some caution.

El Niño typically brings drier than average conditions for eastern Australia during winter–spring, and warmer days across southern Australia. During the autumn months, the influence of El Niño tends to be weaker, but can bring drier conditions to southern Australia.

The Indian Ocean Dipole (IOD) has little influence on Australia from December to April. Current outlooks suggest the IOD is likely to remain neutral for the remainder of the austral autumn, but indicate a positive IOD may form later in winter. A positive IOD typically means drier than average conditions for southern and central Australia during winter-spring.

http://www.bom.gov.au/climate/enso/index.shtml


* ENSO Outlook

An alert system for the El Niño–Southern Oscillation
19 March 2019
Next issue 2 April 2019

El Niño ALERT activated



The ENSO Outlook has been raised to El Niño ALERT. This means the chance of El Niño forming in autumn is around 70%; triple the normal likelihood.

The tropical Pacific Ocean has warmed since late January 2019 and has been touching on El Niño thresholds for three consecutive weeks. Model outlooks suggest this warming is likely to be sustained throughout autumn and into winter. There has been some atmospheric response - but a consistent signal in both the oceans and atmosphere is required for an event to be declared and for climate influences to be felt globally.

El Niño ALERT is not a guarantee that El Niño will occur; it is an indication that most typical precursors of an event are in place. El Niño events typically develop in autumn, mature during winter and spring before decaying in late summer and autumn.

http://www.bom.gov.au/climate/enso/outlook/