La Ninas, and their counterpart El Ninos, have a history of causing substantial weather anomalies. La Nina is often linked, for example, to dryness in northern Argentina and southern US, but persistent rains in Australia.
Official meteorologists give their views on prospects for the La Nina-El Nino cycle.
The latest, mid-October reviews show an increased chance of the La Nina extending into the first couple of months of 2023.
Australian Bureau of Meteorology, December 2o 2022
La Niña continues in the tropical Pacific, but some indicators show signs of declining strength.
Models suggest that ocean temperatures may reach Enso-neutral levels during January or February 2023, and remain at neutral levels until at least April.
Model accuracy for lead times greater than four months is generally lower at this time of year than at other times, so outlooks beyond April should be viewed with caution.
Below-average sea surface temperatures (SSTs) persisted in the central and eastern Pacific Ocean during the past month.
Climate Prediction Division, Japan Meteorological Agency, December 9 2022
In November, the sea surface temperature (SST) for the NINO.3 region was below normal with a deviation of -0.9 degrees Celsius.
The five-month running mean of the NINO.3 SST deviation was -0.7°C in September and was -0.5°C or below for 13 consecutive months up to September.
In the atmosphere, convective activity near the date line over the equatorial Pacific was below normal and easterly winds in the lower troposphere (ie, trade winds) over the central equatorial Pacific were stronger than normal.
These patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events, and indicate that La Niña conditions remain ongoing in the equatorial Pacific.
JMA’s seasonal ensemble prediction system predicts that the Niño.3 index starts to rise in January associated with eastward migration of warm subsurface water in the western to central equatorial Pacific, and it will be near normal in the end of boreal winter.
In conclusion, it is likely that La Niña conditions transfer to Enso-neutral conditions by the end of boreal winter (80%).
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| October-to-February | 90 | 10 | 0 |
| November-to-March | 50 | 50 | 0 |
| December-to-April | 20 | 80 | 0 |
| January-to-May | 10 | 20 | 10 |
| February-to-June | 0 | 80 | 20 |
| Data in percent | |||
US NOAA Climate Prediction Center, December 8 2022
Low-level easterly wind anomalies and upper-level westerly wind anomalies were evident across most of the equatorial Pacific throughout the month. The convection pattern continued to show suppressed convection over the western and central tropical Pacific and enhanced convection over Indonesia.
Overall, the coupled ocean-atmosphere system continued to reflect La Niña.
The most recent IRI plume indicates that La Niña will persist into the northern hemisphere winter. For the dynamical model averages, Enso-neutral is favoured in January-March 2023, while the statistical model average shows the transition to Enso-neutral occurs in February-April 2023.
There is higher confidence that Enso-neutral will emerge by the northern hemisphere spring. In summary, La Niña is expected to continue into the winter, with equal chances of La Niña and Enso-neutral during January-March 2023. In February-April 2023, there is a 71% chance of Enso-neutral.
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| November, December, January | 99 | 1 | 0 |
| December, January, February | 77 | 23 | 0 |
| January, February, March | 50 | 50 | 0 |
| February, March, April | 26 | 71 | 3 |
| March, April, May | 14 | 78 | 8 |
| April, May, June | 9 | 71 | 20 |
| May, June, July | 8 | 60 | 32 |
| June, July, August | 8 | 52 | 40 |
| July, August, September | 9 | 42 | 49 |
| Data in percent | |||
Australian Bureau of Meteorology, December 6 2022
La Niña continues in the tropical Pacific. Atmospheric and oceanic indicators of the El Niño–Southern Oscillation (Enso) reflect a mature La Niña.
Models suggest a return to Enso-neutral in January or February 2023.
Australian Bureau of Meteorology, October 25 2022
La Niña continues. In the tropical Pacific Ocean both atmospheric and oceanic indicators of the El Niño–Southern Oscillation (Enso) are consistent with an established La Niña, including tropical Pacific sea surface temperatures, the southern oscillation index, trade wind strength, and equatorial cloudiness.
Models indicate a return to Enso-neutral conditions (neither La Niña nor El Niño) early in 2023.
US NOAA Climate Prediction Center, October 12 2022
Below-average sea surface temperatures (SSTs) continued across the central and eastern equatorial Pacific Ocean during September. Most of the Niño indices decreased during the past month, with the latest weekly index values spanning -0.8 Celsius to -1.6 Celsius.
Overall, the coupled ocean-atmosphere system continued to reflect La Niña.
The most recent IRI plume forecast of the Niño-3.4 SST index indicates La Niña will persist into the Northern Hemisphere winter 2022-23, and then transition to Enso-neutral in January-March 2023.
The forecaster consensus for this month favours a slightly later transition to Enso-neutral, during February-April 2023, which is consistent with the latest North American Multi-Model Ensemble. However, predicting the timing of transitions is challenging, and there continues to be uncertainty over how long La Niña may last.
In summary, there is a 75% chance of La Niña during the northern hemisphere winter (December-February) 2022-23, with a 54% chance for Enso-neutral in February-April 2023.
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| September, October, November | 100 | 0 | 0 |
| October, November, December | 95 | 5 | 0 |
| November, December, January | 86 | 14 | 0 |
| December, January, February | 75 | 25 | 0 |
| January, February, March | 59 | 39 | 2 |
| February, March, April | 43 | 54 | 3 |
| March, April, May | 26 | 67 | 7 |
| April, May, June | 16 | 69 | 15 |
| May, June, July | 12 | 62 | 26 |
| Data in percent | |||
Climate Prediction Division, Japan Meteorological Agency, October 11 2022
In September, the sea surface temperature (SST) for the NINO.3 region was below normal with a deviation of -0.9 Celsius. The five-month running mean of the NINO.3 SST deviation (NINO.3 index) was -0.7° Celsius in July 2022 and was -0.5 Celsius or below for 11 consecutive months up to July.
Equatorial Pacific SSTs were above normal in western part and below normal in central to eastern parts. Subsurface temperatures were above normal in western part and below normal in central to eastern parts. In the atmosphere, convective activity near the date line over the equatorial Pacific was below normal.
These patterns in the atmosphere and ocean… indicate that La Niña conditions remain ongoing in the equatorial Pacific.
JMA’s seasonal ensemble prediction system predicts that trade winds over the central equatorial Pacific continue to be stronger than normal until boreal winter due to the atmosphere-ocean interaction. The interaction will make NINO.3 index below -0.5 Celsius until boreal early winter.
Then, associated with eastward migration of warm subsurface water in the western equatorial Pacific, Niño.3 index starts to rising, and it will be near normal in boreal spring.
In conclusion, it is likely that La Niña conditions continue (90%) until boreal early winter, and the probability decreases to 60% by the end of the winter.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| August-to-December | 80 | 20 | 0 |
| September-to-January | 80 | 20 | 0 |
| October-to-February | 90 | 10 | 0 |
| November-to-March | 80 | 20 | 0 |
| December-to-April | 60 | 40 | 0 |
| Data in percent | |||
Australian Bureau of Meteorology, October 11 2022
La Niña continues in the tropical Pacific, and is likely to persist into early 2023.
Both atmospheric and oceanic indicators of the El Niño–Southern Oscillation (Enso) are consistent with an established La Niña, including tropical Pacific sea surface temperatures, the southern oscillation index (SOI), trade wind strength, and equatorial cloudiness.
Models indicate the La Niña is likely to decline over spring, with a return to Enso-neutral conditions (neither La Niña nor El Niño) early in 2023. Sea surface temperatures in the tropical Pacific remain similar, compared to two weeks ago. The SOI remains well above La Niña thresholds.
Australian Bureau of Meteorology, September 27 2022
La Niña is underway in the tropical Pacific and the Bureau’s Enso Outlook remains at “La Niña”.
La Niña increases the chance of above average rainfall for northern and eastern Australia during spring and summer.
Both atmospheric and oceanic indicators of the El Niño–Southern Oscillation (Enso) are consistent with an established La Niña, including tropical Pacific sea surface temperatures, the Southern Oscillation Index (SOI), trade wind strength, and equatorial cloudiness.
Models indicate the La Niña may peak during [southern hemisphere] spring and return to neutral conditions early in 2023. Sea surface temperatures in the tropical Pacific have weakened a little compared to two weeks ago while the SOI has continued to rise and is currently well above La Niña thresholds.
Australian Bureau of Meteorology, September 13 2022
The bureau’s Enso outlook has been raised to “La Nina”.
Key atmospheric and oceanic indicators of the El Niño-southern 0scillation (Enso) show an established La Niña.
Tropical Pacific sea surface temperatures have been cooling since June and are now at La Niña thresholds. Atmospheric indicators including the southern oscillation index (SOI), trade wind strength, and equatorial cloudiness are also displaying patterns typical of a La Niña event.
Models indicate this La Niña event may peak during the [southern hemisphere] spring and return to neutral conditions early in 2023. La Niña events increase the chances of above-average rainfall for northern and eastern Australia during spring and summer.
The negative Indian Ocean Dipole (IOD) event continues.
When a La Niña and negative IOD combine, it further increases the likelihood of above average rainfall over Australia, particularly in the eastern half of the continent.
Climate Prediction Division, Japan Meteorological Agency, September 9 2022
In August, the sea surface temperature (SST) for the NINO.3 region was below normal with a deviation of -0.5°C.
In the atmosphere, convective activity near the date line over the equatorial Pacific was below normal and easterly winds in the lower troposphere (ie trade winds) over the central equatorial Pacific were stronger than normal.
These patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events, and indicate that La Niña conditions remain ongoing in the equatorial Pacific.
Subsurface cold water volume observed in the central and eastern equatorial Pacific in August is expected to contribute to maintain cold SSTs in the eastern parts in boreal [northern hemisphere] autumn.
JMA’s seasonal ensemble prediction system predicts that trade winds over the central equatorial Pacific continue to be stronger than normal until boreal winter due to the atmosphere-ocean interaction.
These anomalies in the atmosphere will make NINO.3 index below -0.5°C until boreal winter.
In conclusion, it is likely that La Niña conditions continue (70%) until boreal winter.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| July-to-November | 80 | 20 | 0 |
| August-to-December | 80 | 20 | 0 |
| September-to-January | 80 | 20 | 0 |
| October-to-February | 70 | 30 | 0 |
| November-to-March | 60 | 40 | 0 |
| Data in percent | |||
US NOAA Climate Prediction Center, September 8 2022
During August, below-average sea surface temperatures (SSTs) persisted across the central and east-central equatorial Pacific Ocean.
Low-level easterly wind anomalies and upper-level westerly wind anomalies continued across most of the equatorial Pacific. Convection and rainfall remained suppressed over the western and central tropical Pacific and enhanced over Indonesia.
Overall, the coupled ocean-atmosphere system continued to reflect La Niña.
The most recent IRI plume forecast of the Niño-3.4 SST index indicates La Niña will persist into the northern hemisphere winter 2022-23.
At this time, the forecaster consensus sides with the statistical models, although there is still large uncertainty over how long La Niña will last and when it will transition to Enso-neutral.
In summary, La Niña is favoured to continue through northern hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| August, September, October | 97 | 3 | 0 |
| September, October, November | 91 | 9 | 0 |
| October, November, December | 89 | 11 | 0 |
| November, December, January | 80 | 20 | 0 |
| December, January, February | 65 | 33 | 2 |
| January, February, March | 54 | 43 | 3 |
| February, March, April | 38 | 56 | 6 |
| March, April, May | 22 | 67 | 11 |
| April, May, June | 16 | 67 | 17 |
| Data in percent | |||
World Meteoroligical Organization, August 31 2022
La Niña conditions in the tropical Pacific have persisted and strengthened as trade winds intensified during mid-July to mid-August.
It is likely that these conditions will continue at least for the remainder of 2022, becoming the first “triple-dip” La Niña event of the 21st century.
WMO Global Producing Centres of Long-Range Forecasts predict the continuation of the current La Niña over the next six months, with a 70% chance in September-November2022but gradually decreasing to 55% in December-February 2022/2023.
Australian Bureau of Meteorology, August 30 2022
The bureau’s Enso outlook continues at La Niña “alert”, indicating at least a 70% chance of La Niña reforming later this year.
This is around triple the normal likelihood.
Australian Bureau of Meteorology, August 16 2022
The bureau’s Enso outlook has been raised to La Niña “alert”.
This is due to both renewed cooling in the tropical Pacific Ocean as well as climate models indicating La Niña is likely during the austral spring and early summer.
Historically, when La Niña alert criteria have been met, La Niña has subsequently developed around 70% of the time. This is approximately triple the normal likelihood.
US NOAA Climate Prediction Center, August 11 2022
During the past month, below-average sea surface temperatures (SSTs) expanded across the central and eastern equatorial Pacific Ocean.
Low-level easterly wind anomalies and upper-level westerly wind anomalies persisted across most of the equatorial Pacific. Convection and rainfall remained suppressed over the western and central tropical Pacific and enhanced over Indonesia.
Overall, the coupled ocean-atmosphere system remained consistent with an ongoing La Niña.
The most recent IRI plume average for the Niño-3.4 index forecasts La Niña to persist into the Northern Hemisphere winter 2022-23. The forecaster consensus, supplemented with the latest models from the North American multi-model ensemble (NMME), concurs that La Niña is the most likely outcome during the fall and winter.
While a majority of NMME models suggest that La Niña will transition to Enso-neutral in January-March, forecasters are split on this outcome resulting in equal forecast probabilities for that season.
In summary, La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% in the coming season to 60% during December-February 2022-23.
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| July, August, September | 86 | 14 | 0 |
| August, September, October | 80 | 20 | 0 |
| September, October, November | 80 | 20 | 0 |
| October, November, December | 79 | 20 | 1 |
| November, December, January | 72 | 27 | 1 |
| December, January, February | 60 | 36 | 4 |
| January, February, March | 47 | 47 | 6 |
| February, March, April | 32 | 59 | 9 |
| March, April, May | 18 | 68 | 14 |
| Data in percent | |||
Climate Prediction Division, Japan Meteorological Agency, August 10 2022
Atmospheric and oceanic indicators suggest ongoing La Niña conditions in the equatorial Pacific.
It is possible that La Niña conditions transfer to Enso-neutral (40%) during boreal [northern hemisphere] autumn, but it is more likely that the conditions continue (60%) until early winter.
In July 2022… although the sea surface temperature (SST) deviation temporarily rose to near normal, these patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events and the NINO.3 index was below -0.5°C, and indicate that La Niña conditions remain ongoing in the equatorial Pacific.
Subsurface cold water volume observed in the central equatorial Pacific is expected to migrate eastward and slightly decrease SSTs in the eastern parts in boreal autumn. JMA’s seasonal ensemble prediction system predicts that the NINO.3 index will remain around -0.5°C until boreal early winter due to stronger trade winds.
In conclusion, it is possible that La Niña conditions transfer to Enso -neutral (40%) during boreal autumn, but it is more likely that the conditions continue (60%) until early winter.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| June-to-October | 70 | 30 | 0 |
| July-to-November | 60 | 40 | 0 |
| August-to-December | 60 | 40 | 0 |
| September-to-January | 60 | 40 | 0 |
| October-to-February | 60 | 40 | 0 |
| Data in percent | |||
Australian Bureau of Meteorology, August 2 2022
The bureau’s Enso outlook remains at La Niña “watch”, meaning there is around a 50% chance (double the normal likelihood) of La Niña forming later in 2022. This is a result of current observations and model outlooks.
Australian Bureau of Meteorology, July 19 2022
The bureau’s Enso Outlook is at La Niña “watch”, meaning there is about a 50% chance (double the normal likelihood) of La Niña forming later in 2022.
El Niño–Southern Oscillation (Enso) ocean indicators are at neutral levels. However, some atmospheric indicators, such as the southern oscillation index, show a residual La Niña-like signal. Trade winds have recently re-strengthened in the central to western Pacific.
Most climate models surveyed by the bureau indicate Enso is likely to remain neutral through the southern hemisphere winter. But four of the seven models surveyed by the bureau suggest La Niña could return in spring, with three models persisting at neutral Enso levels.
US NOAA Climate Prediction Center, July 14 2022
La Niña is favoured to continue through 2022 with the odds for La Niña decreasing into the northern hemisphere late summer (60% chance in July-September 2022) before increasing through the Northern Hemisphere fall and early winter 2022 (62-66% chance).
During June, below-average sea surface temperatures (SSTs) weakened across most of the central and eastern equatorial Pacific Ocean with SSTs returning to near-average in the east-central Pacific, as reflected by the Niño indices, which ranged from -0.4°C to -1.2°C during the past week.
Low-level easterly wind anomalies prevailed in the western and central equatorial Pacific, while upper-level westerly wind anomalies continued over most of the equatorial Pacific. Convection remained suppressed over the western and central Pacific and enhanced over Indonesia.
Overall, the coupled ocean-atmosphere system was consistent with La Niña conditions.
The most recent IRI/CPC plume average for the Niño-3.4 SST index now forecasts La Niña to persist into the Northern Hemisphere winter 2022-23. The forecaster consensus also predicts La Niña to persist during the remainder of 2022, with odds for La Niña remaining at 60% or greater through early winter.
Climate Prediction Division, Japan Meteorological Agency, July 11 2022
Atmospheric and oceanic indicators suggest ongoing La Niña conditions in the equatorial Pacific.
It is possible that La Niña conditions transfer to Enso-neutral (40%) during boreal [northern hemisphere] summer, but it is more likely that the conditions continue (60%) until the end of autumn.
In June, the sea surface temperature (SST) for the NINO.3 region was below normal with a deviation of -0.7°C… In the atmosphere, convective activity near the date line over the equatorial Pacific was below normal and easterly winds in the lower troposphere (ie, trade winds) over the central equatorial Pacific were stronger than normal. These patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events, and indicate that La Niña conditions remain ongoing in the equatorial Pacific.
Subsurface warm water volume observed in the central equatorial Pacific is expected to migrate eastward and slightly increase SSTs in the eastern parts in boreal summer. JMA’s seasonal ensemble prediction system predicts that NINO.3 SSTs will slightly increase in boreal summer, but due to stronger trade winds, the NINO.3 index will remain around -0.5°C until the end of boreal autumn.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| April-to-August | 90 | 10 | 0 |
| May-t0-September | 80 | 20 | 0 |
| June-to-October | 70 | 30 | 0 |
| July-to-November | 60 | 40 | 0 |
| August-to-December | 60 | 40 | 0 |
| September-to-January | 60 | 40 | 0 |
| Data in percent | |||
Australian Bureau of Meteorology, July 5 2022
The bureau’s Enso outlook status is at La Niña “watch”.
Most climate models surveyed by the bureau indicate Enso is likely to remain neutral through the southern hemisphere winter. Four of the seven models surveyed by the bureau suggest La Niña could return in spring, with the remaining three models persisting at neutral Enso levels.
Australian Bureau of Meteorology, June 21 2022
The 2021-22 La Niña event has reached an end, with a majority of indicators currently at neutral levels. However, some model outlooks suggest La Niña may reform later in 2022.
As a result, the Bureau’s ENSO Outlook status has moved to La Niña “watch”. La Niña watch means there is around a 50% chance of La Niña forming later in 2022. This is approximately double the normal likelihood.
World Meteorological Organization, June 10 2022
There is a high probability that the ongoing protracted La Niña event, which has affected temperature and precipitation patterns and exacerbated drought and flooding in different parts of the world, will continue until at least August and possibly to the northern hemisphere fall and start of winter.
Some long-lead predictions even suggest that it might persist into 2023. If so, it would only be the third “triple-dip La Niña” (three consecutive northern hemisphere winters of La Niña conditions) since 1950, according to WMO.
The ongoing drought in the Horn of Africa and southern South America bear the hallmarks of La Niña, as does the above average rainfall in South East Asia and Australasia and predictions for an above average Atlantic hurricane season.
The current La Niña event started in September 2020 and continued through mid-May 2022 across the tropical Pacific.
There was a temporary weakening of the oceanic components of La Niña during January and February 2022, but it has strengthened since March 2022.
WMO Global Producing Centers for Long Range Forecasts indicate that there is about a 70% chance of the current La Niña conditions extending into boreal [northern hemisphere] summer 2022, and about 50-60% during July-September 2022.
There are some indications that the probability may increase again slightly during the boreal fall of 2022 and early boreal winter of 2022-23.
Climate Prediction Division, Japan Meteorological Agency, June 10 2022
Subsurface warm water volume observed in the western equatorial Pacific is expected to migrate eastward and slightly increase SSTs (sea surface temperatures) in the eastern parts in boreal summer. JMA’s seasonal ensemble prediction system predicts that NINO.3 SSTs will slightly increase in boreal summer, and the NINO.3 index will remain around -0.5°C until boreal autumn.
In conclusion, La Niña conditions are likely to continue (70%) until early boreal summer, and subsequently it is more likely to transfer to ENSO-neutral (60%) by the end of summer than to continue (40%) until boreal autumn.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| March-to-July | 80 | 20 | 0 |
| April-t0-August | 70 | 30 | 0 |
| May-t0-September | 50 | 50 | 0 |
| June-to-October | 40 | 60 | 0 |
| July-to-November | 40 | 60 | 0 |
| August-to-December | 40 | 60 | 0 |
| Data in percent | |||
US NOAA Climate Prediction Center, June 9 2022
The most recent IRI/CPC plume average for the Niño-3.4 SST index forecasts La Niña to persist into the northern hemisphere winter 2022-23 [Fig. 6]. This is now in greater agreement with the forecast consensus this month, which also predicts La Niña to continue into the winter.
However, it is clear that recent observed oceanic and atmospheric anomalies have weakened and this is anticipated to continue through the summer. Uncertainty remains over whether La Niña may transition to ENSO-neutral during the summer, with forecasters predicting a 52% chance of La Niña and a 46% chance of ENSO-neutral during July-September 2022. After this season, the forecast is for renewed cooling, with La Niña favoured during the fall and early winter.
In summary, though La Niña is favoured to continue through the end of the year, the odds for La Niña decrease into the northern hemisphere late summer (52% chance in July-September 2022) before slightly increasing through the northern hemisphere fall and early winter 2022 (58-59% chance).
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| May, June, July | 95 | 5 | 0 |
| June, July, August | 64 | 36 | 0 |
| July, August, September | 52 | 46 | 2 |
| August, September, October | 54 | 43 | 3 |
| September, October, November | 58 | 39 | 3 |
| October, November, December | 59 | 37 | 4 |
| November, December, January | 58 | 37 | 5 |
| December, January, February | 51 | 43 | 6 |
| January, February, March | 45 | 48 | 7 |
| Data in percent | |||
Australian Bureau of Meteorology, May 24
The 2021-22 La Niña event continues in the tropical Pacific.
Some indicators of La Niña, including tropical Pacific sea surface temperatures and equatorial cloudiness near the date line, have seen little change over the past fortnight. However, beneath the surface of the tropical Pacific, waters have continued their gradual warming away from La Niña levels. The southern oscillation index (SOI) is easing slowly from its recent very high positive values, while trade winds have been close to normal over the past fortnight.
Most climate models surveyed by the bureau indicate a return to neutral Enso during the southern hemisphere winter. Two of the seven models maintain La Niña conditions through the southern [hemisphere] winter.
Even if La Niña eases, the forecast sea surface temperature pattern in the tropical Pacific still favours average-to-above-average winter rainfall for eastern Australia.
Climate Prediction Division, Japan Meteorological Agency, May 12
In April 2022, the NINO.3 SST [sea surface temperature] was below normal with a deviation of -1.0°C. SSTs in the equatorial Pacific were below normal in the central to eastern parts.
In the atmosphere, convective activity near the date line over the equatorial Pacific was below normal and easterly winds in the lower troposphere (ie, trade winds) over the central equatorial Pacific were stronger than normal.
These patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events and indicate that La Niña conditions continue in the equatorial Pacific.
The subsurface warm water volume observed in the western equatorial Pacific is expected to migrate eastward and slightly increase SSTs in the eastern parts in boreal [northern hemisphere] summer. JMA’s seasonal ensemble prediction system predicts that the NINO.3 SST slightly increases in boreal summer, then persists to be close to -0.5°C until boreal autumn.
In conclusion, the La Niña conditions are likely to continue (70%) until early boreal summer, then it is equally likely (50%) that the La Niña conditions continue or Enso-neutral conditions present until boreal autumn.
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| March-to-July | 80 | 20 | 0 |
| April-t0-August | 70 | 30 | 0 |
| May-t0-September | 50 | 50 | 0 |
| June-to-October | 50 | 50 | 0 |
| July-to-November | 50 | 50 | 0 |
| Data in percent | |||
US NOAA Climate Prediction Center, May 12 2022
Below-average sea surface temperatures (SSTs) persisted during April across most of the central and eastern equatorial Pacific Ocean.
Overall, the coupled ocean-atmosphere system reflected the continuation of La Niña.
The most recent IRI/CPC plume average for the Niño-3.4 SST index forecasts borderline La Niña conditions during the Northern Hemisphere summer, with increasing odds for La Niña into the fall.
Similar to last month, the forecaster consensus predicts Niño-3.4 index values to weaken into the summer, but remaining below the threshold of La Niña (Niño-3.4 values equal to or less than -0.5°C).
In the near-term, westerly wind anomalies are predicted for mid-late May which supports the weakening of below-average surface and subsurface oceanic temperatures in the coming months.
However, much of the model guidance is also hinting at a re-strengthening of La Niña conditions again in the fall and upcoming winter.
In summary, though La Niña is favoured to continue, the odds for La Niña decrease into the late Northern Hemisphere summer (58% chance in August-October) before slightly increasing through the Northern Hemisphere fall and early winter (61% chance).
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| April, May, June | 100 | 0 | 0 |
| May, June, July | 87 | 13 | 0 |
| June, July, August | 69 | 31 | 0 |
| July, August, September | 59 | 39 | 2 |
| August, September, October | 58 | 38 | 4 |
| September, October, November | 61 | 35 | 4 |
| October, November, December | 61 | 34 | 5 |
| November, December, January | 61 | 34 | 5 |
| December, January, February | 58 | 37 | 5 |
| Data in percent | |||
Australian Bureau of Meteorology, May 11
The 2021-22 La Niña event continues in the tropical Pacific, with little change in strength in the past few weeks.
Several indicators of La Niña, including tropical Pacific sea surface temperatures, cloudiness near the date line, and the southern oscillation index (SOI), have maintained or slightly increased their strength over the past fortnight. However, beneath the surface of the tropical Pacific, waters have warmed closer to neutral El Niño–southern oscillation (Enso) levels.
Most climate models surveyed by the Bureau indicate a return to neutral Enso by the early southern hemisphere winter. Only one of seven models continues La Niña conditions through the southern winter. La Niña conditions increase the chances of above average rainfall for much of eastern Australia, while neutral Enso has little influence on rainfall patterns.
US NOAA Climate Predication Center, April 14 2022
During March, La Niña continued with below-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean.
For the monthly average, low-level easterly wind anomalies prevailed across the western and central Pacific, and upper-level westerly wind anomalies remained over the east-central Pacific. Suppressed convection remained significant around the date line and was enhanced over the Philippines and South East Asia. Overall, the coupled ocean-atmosphere system reflected the continuation of La Niña.
The most recent IRI/CPC plume average for the Niño-3.4 SST index forecasts a transition to ENSO-neutral during the northern hemisphere summer. This month, the forecaster consensus predicts Niño-3.4 index values to weaken into the summer but remain below the threshold of La Niña.
The change in the consensus forecast to slightly favouring the continuation of La Nina is primarily based on recent model runs from the North American Multi-Model Ensemble… While La Niña is slightly favoured through the fall, there is still a considerable amount of uncertainty, given the combined 45-50% chance for Enso-neutral or El Niño from July-September onwards.
In summary, La Niña is favoured to continue through the northern hemisphere summer (59% chance during June-August), with a 50-55% chance through the fall.
| Probabalistic La Nina – El Nino forecast, CPC/IRI | |||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| March, April, May | 100 | 0 | 0 |
| April, May, June | 89 | 11 | 0 |
| May, June, July | 73 | 27 | 0 |
| June, July, August | 59 | 40 | 1 |
| July, August, September | 52 | 44 | 4 |
| August, September, October | 51 | 42 | 7 |
| September, October, November | 53 | 39 | 8 |
| October, November, December | 54 | 37 | 9 |
| November, December, January | 53 | 37 | 10 |
| Data in percent | |||
Climate Prediction Division, Japan Meteorological Agency, April 11
In March, the NINO.3 SST was below normal with a deviation of -0.7 degrees Celsius. SSTs in the equatorial Pacific were below normal in the central to eastern parts. Subsurface temperatures were above normal in the western part and below normal in the central part… These patterns in the atmosphere and ocean are consistent with features commonly seen in past La Niña events and indicate that La Niña conditions continue in the equatorial Pacific.
JMA’s seasonal ensemble prediction system predicts that the NINO.3 SST persists to be below -0.5 degrees Celsius until end of boreal spring, then it rises and comes closer to normal in boreal summer.
In conclusion, the La Niña conditions are more likely to continue (60%) until the end of boreal spring than not to continue (40%), and transfer to ENSO-neutral in boreal summer (70%).
| Probabalistic La Nina – El Nino forecast, JMA |
|||
| Season | La Niña | Neutral | El Niño |
|---|---|---|---|
| February-to-June | 80 | 20 | 0 |
| March-to-July | 60 | 40 | 0 |
| April-t0-August | 30 | 70 | 0 |
| May-t0-September | 30 | 70 | 0 |
| June-to-October | 30 | 70 | 0 |
| Data in percent | |||
