ENSO Wrap-Up
Current state of the Pacific and Indian oceans


Weekly sea surface temperatures

Graphs of the table values

Monthly sea surface temperatures

Graphs of the table values

5-day sub-surface temperatures

Monthly temperatures

Southern Oscillation Index

30-day SOI values for the past two years
Select to see full-size map of 30-day Southern Oscillation Index values for the past two years, updated daily.

Trade winds

5-day SST and wind anomaly from TAO/TRITON
Select to see full-size map of 5-day SST and wind anomaly from TAO/TRITON.

Cloudiness near the Date Line

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ENSO outlooks

NINO3.4 SST plumes from POAMA forecasts, updated daily
Select to see full-size map of NINIO3.4 SST plumes from POAMA forecasts, updated daily.

Indian Ocean Dipole outlooks

IOD SST plumes from POAMA forecasts, updated daily
Select to see full-size map of IOD SST plumes from POAMA forecasts, updated daily.

Sea surface temperatures (SSTs) across the central Pacific Ocean are slightly warmer than average along the eastern half of the equatorial Pacific.

The latest values for the week ending 17 June are: NINO3 +0.4 °C, NINO3.4 +0.3 °C and NINO4 +0.4 °C. Persistent NINO3 or NINO3.4 values warmer than +0.8 °C are typical of El Niño, while persistent values cooler than −0.8 °C typically indicate La Niña.

Warmer than average SSTs (more than 1 °C above average) persist in areas of the South Pacific Ocean and the Tasman Sea.

Around the north of Australia SSTs are generally near average. Further north, areas of weak warm anomalies remain in areas across the Maritime Continent to the north of Papua New Guinea.

The El Niño–Southern Oscillation (ENSO) remains neutral. However, latest model outlooks and recent warming in the tropical Pacific Ocean indicates that the chance of El Niño forming in spring has increased. As a result, the Bureau's ENSO Outlook status has moved to El Niño WATCH. El Niño WATCH means that the likelihood of El Niño forming in 2018 is approximately 50%; double the normal chance.

Oceanic indicators are currently neutral—neither El Niño nor La Niña—but show some signs of potential El Niño development. Sea surface temperatures in the eastern Pacific Ocean, though currently neutral, have been slowly warming since April. Importantly, waters below the surface of the tropical Pacific are now warmer than average—a common precursor to El Niño.

The majority of international climate models surveyed by the Bureau forecast the tropical Pacific Ocean will continue to warm but stay in the neutral range during July and August. However, five of eight models indicate the ocean warmth is likely to reach El Niño thresholds in the southern hemisphere spring, while a sixth model falls just short.

During El Niño, rainfall in eastern Australian is typically below average during winter and spring. A neutral ENSO phase has little effect on Australian climate.

The Indian Ocean Dipole (IOD) remains neutral. Five of six climate models indicate the IOD is likely to remain neutral in the coming months, and one model suggests a positive IOD.

Cloudiness near the Date Line has been generally below average since late February. While reduced cloudiness near the Date Line is typically a sign of La Niña, the overall pattern of cloudiness across the Pacific is more typical of neutral ENSO.

Equatorial cloudiness near the Date Line typically increases during El Niño (negative OLR anomalies) and decreases during La Niña (positive OLR anomalies).

Trade winds for the 5 days ending 17 June are near average across much of the equatorial Pacific. However, over the central equatorial Pacific, trade winds for the last five days have been weaker than average.

During La Niña events, there is a sustained strengthening of the trade winds across much of the tropical Pacific, while during El Niño events there is a sustained weakening, or even reversal, of the trade winds.

All but one of the eight surveyed international climate models predict further warming of central equatorial Pacific sea surface temperatures (SSTs) over the coming months.

During the remainder of the southern hemisphere winter, all models forecast central Pacific SSTs to remain within neutral values. However, five of the eight models reach El Niño levels during spring, with a sixth model falling just short of the threshold value.

Sea surface temperature (SST) anomalies for May show SSTs were near average across nearly the entire tropical Pacific Ocean, although warm anomalies were present across parts of the Maritime Continent, continuing across the North Pacific to the east of Japan and through the mid-latitudes of the central North Pacific Ocean, and across most of the South Pacific.

The May value for NINO3 was 0.0 °C, NINO3.4 0.0 °C, and NINO4 +0.2 °C.

The 30-day Southern Oscillation Index (SOI) to 17 June was −2.2, and the 90-day SOI was +2.3. The SOI has been within the neutral range since late April.

Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between +7 and −7 generally indicate neutral conditions.

The Indian Ocean Dipole (IOD) is currently neutral. The weekly index value to 17 June was −0.55 °C.

Five of the six international climate models surveyed by the Bureau anticipate that the IOD will remain neutral until at least the southern hemisphere spring. However, one model indicates a positive IOD is likely to develop in the next month, with another approaching positive IOD thresholds during late winter and early spring, but remaining neutral.

The four-month sequence of sub-surface temperature anomalies (to May) shows the decay of shallow cool anomalies in the eastern equatorial Pacific Ocean over February to May, and the eastward propagation of a pool of warmer than average water further below the surface. This area of warm anomalies now extends from 140°E to 120°W between about 100 m and 200 m depth.

Sub-surface temperatures for the 5 days ending 17 June show a pool of warmer than average water beneath the surface of the equatorial Pacific across the top 50 m to 150 m depth. Water is more than 3 degrees warmer than average across a large area east of 140°W, and reaches more than 4 degrees warmer than average in a small portion of this area.

The warmest anomalies in this pool of warmer than average water continue to track eastward, and the thermocline, described by the 20 °C contour in the upper panel of the sub-surface temperature animation, continues to lower. This means that further surface warming in the east is likely.

Product code: IDCKGEWW00