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 almost the entire equator.

The latest values for the week ending 15 July are: NINO3 +0.5 °C, NINO3.4 +0.5 °C and NINO4 +0.4 °C. NINO3 and NINO4 have decreased slightly compared to two weeks ago, while NINO3.4 held steady.

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 large areas of the South Pacific Ocean, with weaker warm anomalies also in much of the Tasman Sea.

Around the north of Australia, SSTs are generally near average. Further north, areas of weak warm anomalies persist in some parts of the Maritime Continent.

The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Bureau's ENSO Outlook is at El Niño WATCH, which means the likelihood of El Niño forming in 2018 is approximately 50%; double the normal chance.

Oceanic ENSO indicators remain neutral, but show a general trend towards El Niño. Sea surface temperatures in the equatorial Pacific are about 0.5 degrees warmer than average. Likewise, sub-surface waters in the eastern tropical Pacific are warmer than average, although these have eased slightly in the past fortnight. Atmospheric indicators remain neutral, but the 30-day Southern Oscillation Index has been negative since the middle of June.

Most international climate models surveyed by the Bureau suggest the tropical Pacific will continue to warm. Five of eight models indicate this warming will reach El Niño levels in the southern hemisphere spring, while a sixth model reaches El Niño levels in December.

During El Niño, rainfall in eastern Australian is typically below average during winter–spring and daytime temperatures are also typically warmer than average for southern Australia. A neutral ENSO phase has little effect on Australian climate.

The Indian Ocean Dipole (IOD) remains neutral. Three of six climate models suggest a positive IOD event may develop, with a fourth model close to meeting thresholds. A positive IOD event typically reduces winter–spring rainfall in central and southern Australia, and can exacerbate any El Niño driven rainfall deficiencies.

Cloudiness near the Date Line has fluctuated around average throughout July.

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 15 July are near average across the entire tropical Pacific.

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

Most of the eight surveyed international climate models predict further warming of central equatorial Pacific sea surface temperatures (SSTs) over the coming months. Four of the eight models suggest El Niño thresholds are likely to be reached in October, with six of eight models exceeding the El Niño threshold value during December.

Sea surface temperature (SST) anomalies for June show SSTs were slightly warmer than average across much of the equatorial Pacific Ocean. Warm anomalies were also present across most of the South Pacific, parts of the Maritime Continent, and large parts of the North Pacific.

The June value for NINO3 was 0.4 °C, NINO3.4 0.3 °C, and NINO4 +0.4 °C.

The 30-day Southern Oscillation Index (SOI) to 15 July was −3.4, and the 90-day SOI was −2.5. The SOI has been within the neutral range since late April.

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

The Indian Ocean Dipole (IOD) is currently neutral. The weekly index value to 15 July was −0.13 °C.

Three of the six international climate models surveyed by the Bureau indicate that a positive IOD may develop, with a fourth model close to meeting thresholds.

The four-month sequence of sub-surface temperature anomalies (to June) shows the evolution of a pool of warmer than average water further below the surface, which has tracked eastward over recent months. This area of warm anomalies now extends across the entire equatorial Pacific, with most of the top 200 m of the ocean warmer than average.

Sub-surface temperatures for the 5 days ending 15 July show a pool of warmer than average water beneath the surface of the equatorial Pacific across the top 150 m of the ocean. Water is more than 3 degrees warmer than average in a region about 120°W at 50 to 100 m depth.

The strength of sub-surface warm anomalies has continued to decrease slightly over the past fortnight. The overall pattern, and position of the warmest anomalies, remains similar to two weeks ago.

Product code: IDCKGEWW00