ENSO Update

Select Issue:
Bulletin December 2016 - Summary

The El Niño-Southern Oscillation (ENSO) remains neutral. However ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017 - double the likelihood. However several indicators have shown little or no increase for several weeks, suggesting El Niño development has stalled for now.

Four of eight international climate models suggest tropical Pacific Ocean temperatures may exceed El Niño thresholds during the second half of 2017, down from seven of eight models that were forecasting a possible event in April. Virtually all models have reduced the extent of predicted ocean warming compared to earlier in the year, indicating that if El Niño forms, it is likely to be weak.

In the last few days the Madden-Julian Oscillation moved into the western Maritime Continent and weakened. Most international climate models agree that the MJO will remain weak for the much of the coming two weeks.

The Intertropical Convergence Zone (ITCZ) was by and large suppressed west of the Hawaiian Islands, with the exception of small patches of enhanced rainfall closer to the equator. Further east, May rainfall was closer to the long-term average. In the southwest Pacific, the SPCZ was suppressed over northern and southern Papua New Guinea, most of Fiji, and from Niue east to the southern Cook Islands. The SPCZ was notably enhanced near the Date Line, resulting in above average rainfall for Tuvalu, Tonga and Samoa. Above average rainfall was also received over the Solomon Islands, Vanuatu and northern Cook Islands.

Seasonal rainfall outlooks for June to August 2017 favour below average rainfall for southern Papua New Guinea. Model outlooks vary elsewhere.

The daily coral bleaching map to 1 June shows small patches of Level 1 and 2 alerts to the east of the eastern Kiribati Islands. According to the four-week outlook from 4 June, Level 1 and 2 alerts are expected to develop and/or expand in the northwest tropical Pacific (around Palau) and east of the eastern Kiribati Islands.

Print this part
Bulletin December 2016 - El Nino Oscillation

The El Niño-Southern Oscillation (ENSO) remains neutral. The ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017.

Sea surface temperatures (SSTs) in the central and eastern tropical Pacific Ocean have warmed steadily since the start of the year. In waters near the South American coastline, some areas are now at least 3 °C above average. However, all indicators of ENSO remain within neutral levels.

In the atmosphere, recent fluctuations in the Southern Oscillation Index (SOI) can be attributed to movements in the monsoon trough associated with severe tropical cyclone Debbie, and are not indicative of ENSO.

All international models surveyed suggest that the current steady warming of the tropical Pacific Ocean is likely to continue in the coming months. Seven of eight models indicate that sea surface temperatures will exceed El Niño thresholds during the second half of 2017. However, some caution must be exercised as models have lower accuracy at this time of year.

The 30-day and 90-day Southern-Oscillation Index (SOI) values to 1 April were +5.5 and +1.0 respectively.

Print this part
Bulletin December 2016 - MJO

After strengthening over the Indian Ocean at the end of May, the Madden-Julian Oscillation (MJO) has recently weakened over the Maritime Continent. International climate models agree that the MJO will remain weak over the next week

Large view

Source

Large view

Source

Large view

Source

Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

Print this part
Bulletin December 2016 - Cloud

The March 30-day OLR and TRMM anomaly maps suggest the ITCZ was slightly north of its long-term average position in the western Pacific and suppressed near and east of the Date Line.

Large view

Source

Large view

Source

Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

Print this part
Bulletin December 2016 - Rainfall

Rainfall for the past month was normal for Sola, Pekoa and Aneityum. Below normal rainfall was recorded at Lamap, Bauerfield , Port Vila and Whitegrass.

Using NINO 3.4 SST Anomalies;

The outlook for Sola, Lamap and Anetyum favour above normal rainfall for the coming months with normal being the next most likely.

The outlook for Pekoa and Port Vila favour close to equal chances of normal and above normal for the coming months.

The outlook for Bauerfield favours normal for the coming months with above normal being the next most likely.

The outlook for Whitegrass favours below normal with equal chances of normal and above normal for the coming months.

Large view

Source

Large view

Source

Large view

Source

Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

Print this part
Bulletin December 2016 - SST

For the week ending 23 April, sea surface temperatures (SSTs) in the central equatorial Pacific Ocean were close to average. Warm anomalies were present in the far western Pacific, around eastern Australia and in the eastern Pacific. Anomalies greater than +1 °C were located adjacent to South America; these anomalies have cooled over the past few weeks.

Warm SST anomalies also persist across much of the Pacific south of the equator.
The NINO 3.4 region warmed by 0.2 °C in the past fortnight. The NINO3 SST anomaly for the week ending 23 April was +0.7 °C, with NINO3.4 +0.5 °C and NINO4 +0.2 °C.

Large view

Source

Large view

Source

Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

Print this part
Bulletin December 2016 - MSLP

The March mean sea level pressure (MSLP) anomaly map shows anomalies greater than 1 hPa above normal over Papua new Guinea and further southeast over the southern Solomon Islands, Vanuatu and Fiji. Anomalies greater than 1 hPa below normal were present in the central tropical Pacific east of 160°W.
Areas of above (below) average MSLP usually coincide with areas of suppressed (enhanced) convection and rain throughout the month.

Large view

Source

Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

Print this part
Bulletin December 2016 - Model Outlooks

The APEC multi-model average, UKMO and ECMWF models favour above average rainfall for Palau, western Federated States of Micronesia, southern and eastern Papua New Guinea, Solomon Islands, and central and southeastern Kiribati.

The APEC multi-model outlook is an average of nine dynamical models: APCC, CMCC, CWB, IRI_CA, MSC, NASA, NCEP, PNU and POAMA.

Print this part
Bulletin December 2016 - SPCZ

In the south Pacific, the SPCZ was close to its long-term average position except near the Date Line where is was displaced towards Fiji. The SPCZ also extended much further east than normal to the Southern Line Islands (Kiribati).

Print this part