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TC Watch > ENSO Watch [Refresh] [中文]
 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 |
| 19-Sep-2020 | 1016.20 | 1012.15 | 10.28 (-2.56) | 9.19 (-0.53) | 6.18 (+0.27) |
| 18-Sep-2020 | 1016.88 | 1012.40 | 12.84 (-5.05) | 9.72 (-0.52) | 5.91 (+0.52) |
| 17-Sep-2020 | 1017.63 | 1012.30 | 17.89 (+3.80) | 10.24 (+0.24) | 5.39 (+0.56) |
| 16-Sep-2020 | 1016.94 | 1012.25 | 14.09 (+6.42) | 10.00 (+0.59) | 4.83 (+0.50) |
| 15-Sep-2020 | 1015.56 | 1011.95 | 7.67 (+5.53) | 9.41 (+0.32) | 4.33 (+0.33) |
| 14-Sep-2020 | 1014.93 | 1012.25 | 2.14 (-0.89) | 9.09 (-0.11) | 4.00 (+0.16) |
| 13-Sep-2020 | 1015.13 | 1012.30 | 3.03 (-3.27) | 9.20 (+0.04) | 3.84 (+0.28) |
| 12-Sep-2020 | 1015.73 | 1012.35 | 6.30 (+5.05) | 9.16 (+0.41) | 3.56 (+0.16) |
| 11-Sep-2020 | 1013.23 | 1010.70 | 1.25 (+1.13) | 8.75 (+0.32) | 3.40 (-0.08) |
| 10-Sep-2020 | 1012.89 | 1010.55 | 0.12 (+6.12) | 8.43 (-0.27) | 3.48 (-0.14) |
| 9-Sep-2020 | 1013.81 | 1012.50 | -6.00 (-3.39) | 8.70 (-0.65) | 3.62 (-0.07) |
| 8-Sep-2020 | 1015.48 | 1013.60 | -2.61 (-15.92) | 9.35 (-0.39) | 3.69 (+/-0.00) |
| 7-Sep-2020 | 1015.86 | 1011.30 | 13.31 (+1.13) | 9.74 (+0.17) | 3.69 (+0.07) |
| 6-Sep-2020 | 1015.02 | 1010.65 | 12.18 (+3.62) | 9.57 (-0.34) | 3.62 (+/-0.00) |
| 5-Sep-2020 | 1014.41 | 1010.65 | 8.56 (+1.78) | 9.91 (-0.58) | 3.62 (+0.25) |
| 4-Sep-2020 | 1015.86 | 1012.40 | 6.78 (-5.82) | 10.49 (-0.23) | 3.37 (+0.50) |
| 3-Sep-2020 | 1016.54 | 1012.10 | 12.60 (-7.55) | 10.72 (+0.33) | 2.87 (+0.66) |
| 2-Sep-2020 | 1016.41 | 1010.70 | 20.15 (+1.49) | 10.39 (+0.65) | 2.21 (+0.59) |
| 1-Sep-2020 | 1016.31 | 1010.85 | 18.66 (-2.7) | 9.74 (+0.77) | 1.62 (+0.39) |
| 31-Aug-2020 | 1016.69 | 1011.55 | 21.36 (-1.34) | 8.97 (+1.02) | 1.23 (+0.26) |
| 30-Aug-2020 | 1016.96 | 1011.60 | 22.70 (+4.07) | 7.95 (+1.29) | 0.97 (+0.15) |
| 29-Aug-2020 | 1016.49 | 1011.80 | 18.63 (+8.98) | 6.66 (+1.21) | 0.82 (-0.02) |
| 28-Aug-2020 | 1015.41 | 1012.20 | 9.65 (+10.32) | 5.45 (+0.36) | 0.84 (-0.09) |
| 27-Aug-2020 | 1014.96 | 1013.45 | -0.67 (+5.46) | 5.09 (-0.14) | 0.93 (-0.1) |
| 26-Aug-2020 | 1015.56 | 1014.95 | -6.13 (-2.91) | 5.23 (-0.24) | 1.03 (-0.09) |
| 25-Aug-2020 | 1016.04 | 1014.95 | -3.22 (-14.39) | 5.47 (-0.31) | 1.12 (+0.02) |
| 24-Aug-2020 | 1017.21 | 1013.75 | 11.17 (+1.64) | 5.78 (-0.28) | 1.10 (+0.20) |
| 23-Aug-2020 | 1017.49 | 1014.30 | 9.53 (+/-0.00) | 6.06 (-0.38) | 0.90 (+0.14) |
| 22-Aug-2020 | 1017.44 | 1014.25 | 9.53 (-14.26) | 6.44 (-0.21) | 0.76 (+0.27) |
| 21-Aug-2020 | 1018.19 | 1012.65 | 23.79 | 6.65 | 0.49 |
Charts: 2020 | 2019 | 2018 | 2017 | 2016 | Source: The State of Queensland, Australia
| ENSO Wrap Up (Source: here) |
Issued on 15 September 2020
The Bureau's ENSO Outlook remains at La Niña ALERT. However, further cooling of the surface of the tropical Pacific Ocean is expected. All surveyed international climate models indicate La Niña thresholds will be met from October until at least the end of the year, with most models maintaining these values into early 2021.
Key indicators of ENSO are currently at or approaching La Niña thresholds, indicating that the atmosphere is responding to the changes in the ocean. If current atmospheric patterns and ocean cooling continue until the end of September, it is highly likely that La Niña conditions will be sustained until at least the end of the year.
In the Indian Ocean, values of the Indian Ocean Dipole (IOD) index have risen back into neutral territory. However, five of the six surveyed models indicate values may drop once again, and that negative IOD thresholds could be met in October. To be considered a negative IOD event, these values would need to be sustained for at least eight weeks.
Both La Niña and negative IOD typically increase the chance of above average rainfall across much of Australia during spring. Above average summer rainfall is also typical for much of eastern Australia during La Niña. Current climate outlooks indicate a wetter than average spring for eastern Australia.
The Southern Annular Mode (SAM) is for the rest of September. Positive SAM during spring is typically associated with wetter and cooler than average conditions in parts of eastern Australia.
The Madden–Julian Oscillation (MJO) is currently weak or indiscernible.
Climate change is also influencing the Australian climate. Australia's climate has warmed by around 1.4 °C since 1910, while southern Australia has seen a 10–20% reduction in cool season (April–October) rainfall in recent decades.
SOI summary:
The 30-day Southern Oscillation Index (SOI) for the 30 days ending 13 September was +9.5. The 30-day SOI has been above the La Niña threshold values for most of the past three weeks. The 90-day value remains within the ENSO-neutral range at +5.0.
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.
Sea surface temperature summary:
The sea surface temperature (SST) map for the tropical Pacific Ocean for the week ending 13 September show cool anomalies in the central and eastern Pacific. Cool SST anomalies in the central and eastern equatorial Pacific have continued to strengthen over recent weeks, and extend across the tropics to the south of the equator in the eastern Pacific. Warm anomalies cover the area to the west of the Date Line as well as the Maritime Continent, and waters close to the continent around much of Australia.
The latest values of the three NINO indices in the tropical Pacific for the week ending 13 September were: NINO3 −0.8 °C, NINO3.4 −0.7 °C, NINO4 −0.2 °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.
ENSO outlooks:
All of the international climate models surveyed by the Bureau indicate central tropical Pacific sea surface temperatures in the NINO3.4 region will continue to cool over the coming months. All surveyed international climate models indicate La Niña thresholds will be met from October until at least the end of the year, with five of the eight models maintaining these values into early 2021.
ENSO events—El Niño or La Niña—typically begin to develop during the southern hemisphere autumn to winter, before strengthening in winter to spring.
La Niña typically brings above average spring rainfall to most of Australia.
Last Accessed: Sat Sep 19 2020 17:11:24 HKT
Last Modified: Wed Jul 24 2019
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