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Real-time SOI Data

Numerical data from here and values are calculated using the 1887-1989 base period. This information is usually updated every weekday at 2:00pm (AEST), public holidays excluded.

Date Pressure at Tahiti (hPa) Pressure at Darwin (hPa) Daily value 30-day average SOI 90-day average SOI
24 May 2017 1012.39 1011.55 -5.27 (-1.53) -2.33 (+0.20) -1.78 (-0.01)
23 May 2017 1012.59 1011.55 -3.74 (-6.21) -2.53 (-0.01) -1.77 (+0.08)
22 May 2017 1012.25 1010.40 2.47 (-8.89) -2.52 (+0.02) -1.85 (+0.15)
21 May 2017 1012.26 1009.25 11.36 (-5.97) -2.54 (+0.64) -2.00 (+0.23)
20 May 2017 1013.29 1009.50 17.33 (+10.42) -3.18 (+1.16) -2.23 (+0.41)
19 May 2017 1013.18 1010.75 6.91 (-3.83) -4.34 (+0.58) -2.64 (+0.53)
18 May 2017 1013.63 1010.70 10.74 (+3.37) -4.92 (+0.94) -3.17 (+0.69)
17 May 2017 1013.29 1010.80 7.37 (+1.15) -5.86 (+1.28) -3.86 (+0.53)
16 May 2017 1013.54 1011.20 6.22 (-2.07) -7.14 (+1.39) -4.39 (+0.33)
15 May 2017 1013.86 1011.25 8.29 (+3.37) -8.53 (+1.43) -4.72 (+0.11)
14 May 2017 1013.52 1011.35 4.92 (-1.76) -9.96 (+1.32) -4.83 (-0.1)
13 May 2017 1013.35 1010.95 6.68 (+11.10) -11.28 (+0.76) -4.73 (-0.09)
12 May 2017 1012.55 1011.60 -4.42 (+16.93) -12.04 (-0.51) -4.64 (-0.19)
11 May 2017 1011.54 1012.80 -21.35 (-3.52) -11.53 (-1.22) -4.45 (-0.29)
10 May 2017 1011.50 1012.30 -17.83 (-1.84) -10.31 (-1.24) -4.16 (-0.2)
9 May 2017 1011.09 1011.65 -15.99 (-0.46) -9.07 (-0.93) -3.96 (-0.24)
8 May 2017 1011.70 1012.20 -15.53 (-0.76) -8.14 (-0.67) -3.72 (-0.29)
7 May 2017 1012.65 1013.05 -14.77 (-2.38) -7.47 (-0.65) -3.43 (-0.46)
6 May 2017 1013.16 1013.25 -12.39 (-0.31) -6.82 (-0.47) -2.97 (-0.43)
5 May 2017 1012.90 1012.95 -12.08 (+0.69) -6.35 (-0.29) -2.54 (-0.26)
4 May 2017 1012.81 1012.95 -12.77 (-11.33) -6.06 (-0.26) -2.28 (-0.25)
3 May 2017 1013.24 1011.90 -1.44 (+2.22) -5.80 (+0.44) -2.03 (-0.19)
2 May 2017 1013.05 1012.00 -3.66 (+8.58) -6.24 (+0.23) -1.84 (-0.21)
1 May 2017 1012.23 1012.30 -12.24 (+8.53) -6.47 (-0.16) -1.63 (-0.27)
30 Apr 2017 1011.86 1012.35 -20.77 (-10.6) -6.31 (-0.39) -1.36 (-0.23)
29 Apr 2017 1012.83 1011.85 -10.17 (-10.82) -5.92 (-0.24) -1.13 (-0.06)
28 Apr 2017 1013.58 1011.10 0.65 (-18.02) -5.68 (-0.2) -1.07 (+0.04)
27 Apr 2017 1014.63 1009.65 18.67 (+4.11) -5.48 (+0.62) -1.11 (+0.25)
26 Apr 2017 1014.11 1009.70 14.56 (+16.29) -6.10 (+0.29) -1.36 (+0.09)
25 Apr 2017 1012.45 1010.30 -1.73 -6.39 -1.45




Charts: 2017 | 2016 | 2015 | 2014 | 2013 | Source: The State of Queensland, Australia

ENSO Wrap Up (Source: here)

Issued on 23 May 2017

Tropical Pacific remains warmer than average

The El Niño–Southern Oscillation (ENSO) remains neutral. With the tropical Pacific Ocean warmer than average, and around half the international climate models reaching El Niño levels later in the year, development of El Niño in 2017 cannot be ruled out. The Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is around a 50% chance—double the normal likelihood—of El Niño developing in 2017.

Sea surface temperatures across the central tropical Pacific remained half a degree warmer than average over the past month. This is below the El Niño threshold of +0.8 °C. Further warming in the coming fortnight is unlikely, with trade winds forecast to be stronger than average. All other ENSO indicators are also neutral.

Five of eight international climate models suggest the tropical Pacific Ocean is likely to warm above El Niño thresholds during the second half of 2017. However virtually all models now suggest less warming is likely to occur compared to their previous outlooks, indicating any event may be weak. Models have lower accuracy forecasting El Niño during the autumn months, though accuracy begins to improve from June.

El Niño is often, but not always, associated with a drier than average winter–spring over eastern Australia. Even if El Niño thresholds are not met, Australia may still see some El Niño-like effects if waters in the tropical Pacific Ocean remain warm.

The Indian Ocean Dipole (IOD) remains neutral. Four out of six climate models suggest a positive IOD is likely to develop during winter. A positive IOD is typically associated with a drier than average winter–spring for southern and central Australia.


SOI summary:

The 30-day Southern Oscillation Index (SOI) to 21 May was −3.7 (90-day value −0.9), within neutral territory.

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


Sea surface temperature summary:

For the week ending 21 May, sea surface temperatures (SSTs) in the central to western equatorial Pacific Ocean were close to average. Weak warm SST anomalies persist across the central to eastern equatorial Pacific and much of the South Pacific, including areas immediately south of the equator. Warm anomalies greater than +1 °C were present in the far eastern equatorial Pacific.

The NINO3.4 SST anomaly has remained at around +0.5 °C since mid-April, with NINO3 remaining at or above +0.5 °C since mid-March. Both NINO3.4 and NINO3 are currently at +0.5 °C, while NINO4 is at +0.3 °C.


ENSO outlooks:

Climate models surveyed by the Bureau indicate that El Niño remains possible for the second half of 2017. Five out of the eight surveyed models forecast SSTs in the central Pacific will reach or exceed the El Niño threshold at some point during winter or spring. However, some models show considerable spread across their projections, and three models favour neutral ENSO conditions.

It should be noted that model outlooks that span the southern hemisphere autumn tend to have lower accuracy than outlooks issued at other times of the year, and should be used with some caution. Accuracy begins to improve for outlooks generated in June.

Last Accessed: Thu May 25 2017 01:48:40 HKT
Last Modified: Sun Jul 10 2016

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