ENSO Archives - EconCurrents

NOAA Updates its ENSO Alert on May 9, 2024 – The El Nino Advisory/La Nina Watch Continues. – La Nina Onset a Bit Slower than Prior Estimate – Published May 10, 2024

By Sig Silber May 10, 2024weatherNo Comments

On the second Thursday of every month, NOAA (really their Climate Prediction Center CPC) issues its analysis of the status of ENSO. This includes determining the Alert System Status. NOAA again describes their conclusion as “ENSO Alert System Status: El Nino Advisory La Nino Watch”

The exact timing of the transition is not very clear which will impact the reliability of the Seasonal Outlook to be issued next Thursday. It does look like the onset may be slightly slower than thought last month. This may turn out to be a trend i.e. recognizing that the onset will be less rapid than previously thought. I am just guessing. It is difficult to predict how the phases of ENSO will unfold.

We have included an ENSO Blog article by Emily Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume favors an imminent transition to ENSO-neutral, with La Niña developing during July-September 2024 and then persisting through the Northern Hemisphere winter. The forecast team continues to favor the dynamical model guidance, which suggests La Niña could form as early as June-August 2024, with higher confidence of La Niña during the following seasons. La Niña generally tends to follow strong El Niño events, which also provides added confidence in the model guidance favoring La Niña. In summary, a transition from El Niño to ENSO-neutral is likely in the next month. La Niña may develop in June-August (49% chance) or July-September (69% chance).”

Below is the middle paragraph from the discussion last month.

“The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during late summer 2024. The forecast team continues to favor the dynamical model guidance, which is slightly more accurate than statistical models during this time of year. La Niña tends to follow strong El Niño events, which also provides added confidence in the model guidance favoring La Niña. In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (85% chance), with the odds of La Niña developing by June-August 2024 (60% chance).”

We now provide additional details.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. MAM stands for March/April/May.

Here is the current release of the probabilities:

This chart shows the forecasted progression of the evolution of ENSO from the current El Nino State to Neutral and by the summer to La Nina. This kind of bar chart is not very good at showing uncertainty.

Here is the forecast from last month.

The analysis this month and last month are not very different.

Click on “Read More” to read the rest of this article.

NOAA Updates its ENSO Alert on April 11, 2024 – The El Nino Advisory/La Nina Watch Continues. Not Much Change on the Timing – Published April 11, 2024

By Sig Silber April 12, 2024weatherNo Comments

The exact timing of the transition is not very clear which will impact the reliability of the Seasonal Outlook to be issued next Thursday.

We have included an ENSO Blog article by Emily Becker that includes two very interesting animations. .

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during late summer 2024. The forecast team continues to favor the dynamical model guidance, which is slightly more accurate than statistical models during this time of year. La Niña tends to follow strong El Niño events, which also provides added confidence in the model guidance favoring La Niña. In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (85% chance), with the odds of La Niña developing by June-August 2024 (60% chance).”

Below is the middle paragraph from the discussion last month.

“The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during summer 2024 . While different types of models suggest La Niña will develop, the forecast team favors the dynamical model guidance, which is slightly more accurate for forecasts made during this time of year. Even though forecasts made through the spring season tend to be less reliable, there is a historical tendency for La Niña to follow strong El Niño events. In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (83% chance), with the odds of La Niña developing by June-August 2024 (62% chance).”

We now provide additional details. The level of uncertainty with respect to how this El Nino will play out has changed a bit. NOAA is not quite as confident that we will have a LaNina. It is a slight change.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. MAM stands for March/April/May.

Here is the current release of the probabilities:

Here is the forecast from last month.

The analysis this month and last month are not very different.

Click on “Read More” to read the rest of this article.

Is ENSO Static? Are they all Alike? Is there a Trend? – Posted on April 3, 2024

By Sig Silber April 3, 2024Climate2 Comments

There was a very interesting blog post on ENSO.Gov that tries to assess this El Nino in the context of other El Ninos and I think they have done a very good job. I have reproduced the blog post in this article. Those who want access to any comments that have been submitted to that blog post can find the post HERE. Remember that all posts on the Climate.Gov ENSO Blog are attributed to the author who in this case is Nat Johnson. All the ENSO Blog posts are excellent. This one is beyond excellent.

The above shows that the current El Nino which is winding down has been pretty close to what would be expected from a typical El Nino. It also shows how both the typical El Nino and the current El Nino compare to Normal or Climatology. You can easily see the differences. The analysis is for the Meteorological Winter months of December through February.

There is a lot more to this blog Post so some readers will need to click on “Read More” to access the rest of this very interesting analysis. If you accessed this article via the url you will already have the full article and will not need to click on “Read More”.

NOAA Updates its ENSO Alert on February 8, 2024 – The El Nino Advisory Continues. The La Nina Watch Begins – Timing of the Transition is Uncertain

By Sig Silber February 9, 2024weatherNo Comments

The timing of the transition is not very clear which will impact the reliability of the Seasonal Outlook to be issued next Thursday.

We have included an interesting animation from and a link to an ENSO Blog article by Tom Liberto

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during summer 2024. Even though forecasts made through the spring season tend to be less reliable, there is a historical tendency for La Niña to follow strong El Niño events. The forecast team is in agreement with the latest model guidance, with some uncertainty around the timing of transitions to ENSO-neutral and, following that, La Niña. Even as the current El Niño weakens, impacts on the United States could persist through April 2024 (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (79% chance), with increasing odds of La Niña developing in June-August 2024 (55% chance).”

Below is the middle paragraph from the discussion last month.

“The most recent IRI plume indicates El Niño will gradually weaken and then transition to ENSO-neutral during spring 2024 . Some state-of the-art dynamical climate models suggest a transition to ENSO-neutral as soon as March-May 2024. The forecast team, however, delays this timing and strongly favors a transition to ENSO-neutral in April-June 2024. There are also increasing odds of La Niña in the seasons following a shift to ENSO-neutral. It is typical for El Niño to peak in December/early January, but despite weakening, its impacts on the United States could last through April (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, El Niño is expected to continue for the next several seasons, with ENSO-neutral favored during April-June 2024 (73% chance).”

We now provide additional details. The level of uncertainty with respect to how this El Nino will play out has increased a bit.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. JFM stands for January/February/March.

Here is the current release of the probabilities:

Here is the forecast from last month.

The analysis this month and last month are different. This month the probability of El Nino in MAM is much more than was expected last month. That is important.

NOAA Updates its ENSO Alert on January 11, 2024 – The El Nino Advisory Continues. Disagreement on When it Will End

By Sig Silber January 12, 2024weatherNo Comments

There is not much doubt that we have an El Nino. How long it lasts and its strength remains to be seen. This El Nino has not become a Historical El Nino. We will try to address the slight confusion of when the El Nino will end in this article.

We have included some very interesting graphics from and a link to an interesting ENSO Blog article by Emily Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

Below is the middle paragraph from the discussion last month.

” The most recent IRI plume favors El Niño to continue through the Northern Hemisphere winter 2023-24. Based on the latest forecasts, there is now a 54% chance of a “historically strong” El Niño during the November-January season (³ 2.0°C in Niño-3.4). An event of this strength would potentially be in the top 5 of El Niño events since 1950. While stronger El Niño events increase the likelihood of El Niño-related climate anomalies, it does not imply expected impacts will emerge in all locations or be of strong intensity (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, El Niño is expected to continue through the Northern Hemisphere winter, with a transition to ENSO-neutral favored during April-June 2024 (60% chance;).”

We now provide additional detail. The level of uncertainty with respect to how this El Nino will play out has increased quite a bit.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. DJF stands for December/January/February.

Here is the current release of the probabilities:

This chart shows the forecasted progression of the evolution of ENSO from the current El Nino State to Neutral and by the summer to La Nina.

Here is the forecast from late last month.

The analysis this month and last month are different. This month the probability of El Nino in MAM is much less than was expected last month. That is important.

NOAA Updates its ENSO Alert on December 14, 2023 – The El Nino Advisory Continues. In a Week, NOAA Will Update us on how this Impacts U.S. Weather

By Sig Silber December 15, 2023weatherNo Comments

There is not much doubt that we have an El Nino. How long it lasts and its strength remains to be seen. NOAA may be more conservative compared to some other Weather Advisory Organizations. Some of the other Weather Advisory Organizations are predicting a higher probability for a “Historically Strong” El Nino. I personally believe that this El Nino will be somewhat of an underachiever. We will be finding out over the next two months.

We have included a link to an interesting ENSO Blog article by Emily Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

Below is the middle paragraph from the discussion last month. We see that this month there is an increased chance of a “historically strong” event.

“The most recent IRI plume favors El Niño to continue through the Northern Hemisphere spring 2024. Based on latest forecasts, there is a greater than 55% chance of at least a “strong” El Niño (³ 1.5°C in Niño-3.4 for a seasonal average) persisting through January-March 2024. There is a 35% chance of this event becoming “historically strong” (³ 2.0°C) for the November-January season. Stronger El Niño events increase the likelihood of El Niño-related climate anomalies, but do not necessarily equate to strong impacts (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, El Niño is anticipated to continue through the Northern Hemisphere spring (with a 62% chance during April-June 2024.”

We now provide additional detail but I am keeping this article shorter than usual because nothing much has changed since last month.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. OND stands for October/November/December.

Here is the current release of the probabilities:

You can clearly see the forecast does not extend beyond JAS 2024 and one does see a tail-off in the probabilities for El Nino conditions in the Eastern Pacific after the winter season. Is a return to La Nina in our future?

Here is the forecast from late last month.

The analysis this month and last month are pretty similar.

What about El Nino? September 23, 2023

By Sig Silber September 23, 2023Climate, weatherNo Comments

Since it is almost certain we will have El Nino this winter and a strong one at that, it is useful to think about what that means for precipitation in the lower 48 states.

–

The above shows El Nino winters from 1950 to today organized from upper left to lower right by the strength of the ENSO ONI Index. It may be missing one or even two recent El Ninos. I know how to create this sort of graphic but I prefer to use one that has been created by others. The point is that there is a lot of variation among El Nino winters. In the past, I have done an analysis for the state where I live which is New Mexico to see if the phases of the AMO and PDO seem to have an impact and they do. I am not aware of any published paper on that subject. I have seen papers that look at the impact of the Hawaiin High on how wet certain parts of California get during an El Nino. The fact is we do not really know how El Nino works partly because we have so few El Nino winters to analyze.

–

NOAA Updates its ENSO Alert on September 14, 2023 – The El Nino Advisory Continues. In a Week, NOAA Will Update us on how this Impacts U.S. Weather

By Sig Silber September 15, 2023Climate, weatherNo Comments

There is not much doubt that we have an El Nino. How long it lasts and its strength remains to be seen. NOAA may be more conservative compared to some other Weather Advisory Organizations.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume indicates El Niño will persist through the Northern Hemisphere winter 2023-24. Despite nearly the same ensemble mean amplitude as last month, the shorter forecast horizon means that the odds of at least a “strong” El Niño (≥1.5C for the November-January seasonal average in Niño-3.4) have increased to 71%. However, a strong El Niño does not necessarily equate to strong impacts locally, with the odds of related climate anomalies often lower than the chances of El Niño itself (e.g., CPC’s seasonal outlooks). In summary, El Niño is anticipated to continue through the Northern Hemisphere winter (with greater than 95% chance through January – March 2024; ).”

We now provide additional detail but I am keeping this article shorter than usual because nothing much has changed since last month.

CPC Probability Distribution

Here are the new forecast probabilities. This information in the past has been released twice a month and the first release is based on a survey of Meteorologists, the second is based on model results. The probabilities are for three-month periods e.g. ASO stands for August/September/October. The approach may have changed as IRI (The International Research Institute for Climate and Society, Columbia University Climate School) may no longer be involved. Their website has not been updated this month.

Here is the current release of the probabilities:

You can clearly see the forecast does not extend beyond AMJ 2024 and one does see a tail-off in the probabilities for El Nino conditions in the Eastern Pacific after the winter season. Some Meteorological Agencies see El Nino lasting longer but JAMSTEC showed it ending sooner in the article I posted last night which you can access HERE.

Here is the forecast from late last month.

This showed a slower demise of the El Nino.

Is Global Warming Impacting the ENSO Cycle – August 5, 2023

By Sig Silber August 5, 2023ClimateNo Comments

Is Global Warming impacting the ENSO Cycle? A friend of mine posted an interesting post on this on Climate.Gov and I think it is worth discussing. But we really do not have the ability at this point in time to know if this is happening and if so why.

This introduces the ENSO BLOG post on Climate.gov. Here is the link to the full post.

He provides two pieces of evidence. This is the one that resonated with me.

Presumably, we see higher highs (El Nino) and lower lows (La Nina) since 1960. We do not seem to see higher highs and higher lows which one might expect with warmer oceans but all the values are anomalies that complicate things a lot. Actually, I am not 100% sure of exactly what this data represents. Presumably, it is the 5-month running mean minus the 1981- 2010 climatology. That is slightly different than the usual calculation of the value of the Nino 3.4 Index but it is challenging to compare current values to historical values as the temperature of the ocean surface increases. I will copy Mike McPhaden and ask him if I have described the above correctly – stay tuned. Trying to understand the impact of Global Warming is not simple.

The Footnotes to the post provide useful information

NOAA Updates its ENSO Alert on July 13, 2023 – El Nino is here and 90% Likely to Last through Winter with a 20% Chance of a MegaNino

By Sig Silber July 15, 2023weatherNo Comments

On the second Thursday of every month, NOAA issues its analysis of the status of ENSO. This includes determining the Alert System Status. NOAA again describes their Report as “ENSO Alert System Status: El Nino Watch”

There is not much doubt that we have an El Nino. How long it lasts and its strength remains to be seen.

From the NOAA Analysis:

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume indicates El Niño will persist through the Northern Hemisphere winter 2023-24. Forecasters favor continued growth of El Niño through the fall, peaking this winter with moderate-to-strong intensity (81% chance of November-January Niño-3.4 ≥1.0C). An event that becomes “historically strong” (seasonally averaged Niño-3.4 ≥ 2.0C), rivaling the winters of 1997-98 or 2015-16, has an approximately 1 in 5 chance. In summary, there is a greater than 90% chance that El Niño will continue through the Northern Hemisphere winter.

We now provide additional detail.

CPC Probability Distribution

Here are the new forecast probabilities. This information in the past has been released twice a month and the first release is based on a survey of Meteorologists, the second is based on model results. The probabilities are for three-month periods e.g. JJA stands for June/July/August. The first forecast forecast is used to develop the Seasonal Outlook which will be issued next Thursday so that is what I am focusing on.

Here is the current release of the probabilities:

You can clearly see The forecast does not extend beyond FMA 2024 but one does see a slight tail-off in the probabilities for El Nino conditions in the Eastern Pacific after the winter season.