NOAA Updates its ENSO Alert on December 12, 2024 – Will it be or not? – Published on December 13, 2024

December 13, 2024Posted inweatherNo Comments

“Synopsis:   “La Niña conditions are most likely to emerge in November 2024 – January 2025 (59% chance), with a transition to ENSO-neutral most likely by March-May 2025 (61% chance).“

So we continue to be in ENSO Neutral but NOAA may not want to admit their forecast was wrong so they present it as waiting for La Nina. It is correct that we are in La Nina Watch but it is also correct that we currently still remain in ENSO Neutral.

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 now describes their conclusion as “ENSO Alert System Status: La Nino Watch”

The exact timing of the transition is now perhaps more clear but maybe not.  It should increase the reliability of the Seasonal Outlook to be issued next Thursday. But will it?

BTW this is the Copernicus view of the next three months.

 

The above is a consolidation of a number of models including one of the U.S. models but it is dominated by  European models. The format is different than what NOAA will present next week. It is more technical in nature. Basically this graphic shows the expected average storm track over the three-month period.  It also shows the expected deviation from normal of the level of the 500 MB ((Z500) of air- pressure which is pretty much the midpoint of the atmosphere. Z 500 is often the best way to forecast weather. Remember this is not a weather forecast but a forecast of the average air pressure for the three months.  It will vary from day to day and week to week but the storm track is expected to be further north which usually divides the cold and wet area from the warm and dry area but we are talking about anomalies. I suspect that the NOAA forecast which will be issued next Thursday will be similar to the above. It is suggesting a La Nina pattern.

We have included a very interesting ENSO Blog Post by Emily  Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION (LINK)

The second paragraph is what is important:

“The dynamical models in the IRI plume continue to predict a weak and a short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C. This prediction is also reflected in the latest North American Multi-Model Ensemble (NMME), which continues to predict slightly cooler SSTs and weak La Nina conditions.  The forecast team leaned toward predicting an eventual onset of weak and short-lived La Nina conditions, based on the model guidance and current atmospheric anomalies. Weak La Niña conditions would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña conditions are most likely to emerge in November 2024 – January 2025 (59% chance), with a transition to ENSO-neutral most likely by March-May 2025 (61% chance).”

Below is the middle paragraph from the discussion last month.

“The IRI plume predicts a weak and short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C. The latest North American Multi-Model Ensemble (NMME) forecasts are cooler than the IRI plume and predict a weak La Niña.  Due to this guidance and La Niña-like atmospheric circulation anomalies over the tropics, the team still favors the onset of La Niña, but it is likely to remain weak and have a shorter duration than other historical episodes.  A weak La Niña would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña is most likely to emerge in October-December 2024 (57% chance) and is expected to persist through January-March 2025).”

We now provide additional details.

CPC Probability Distribution

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

Here is the forecast from last month.

The analysis this month and last month are a bit different with again the transition to La Nina being slightly slower than thought last month. Also, the probabilities of a La Nina are lower than estimated last month. This seems to be a trend. The chart is clearer than the discussion in the summary report above.  The La Nina is a bit slower to arrive. I am not sure that we will actually have a La Nina.  However, one should read the Blog Post by Emily Becker, which is discussed later in this article.

Some will need to click on “Read More” to read the rest of this article.

NOAA Updates its ENSO Alert on November 14, 2024 – We Remain in ENSO Neutral or do We?– Published November 15, 2024

November 15, 2024Posted inUncategorizedNo Comments

“Synopsis:   “In summary, La Niña is most likely to emerge in October-December 2024 (57% chance) and is expected to persist through January-March 2025).”

So we are really in ENSO Neutral but NOAA may not want to admit their forecast was wrong so they present it as waiting for La Nina. It is correct that we are in La Nina Watch but it is also correct that we currently remain in ENSO Neutral.

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 now describes their conclusion as “ENSO Alert System Status: La Nino Watch”

The exact timing of the transition is now perhaps more clear which should increase the reliability of the Seasonal Outlook to be issued next Thursday.

We have included an ENSO Blog article by Emily  Becker. It raises the question which I have raised before. With Global Warming, are we measuring the phases of ENSO correctly? This is a very important question. We will discuss this graphic which is provided by Emily Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION (LINK)

The second paragraph is what is important:

The IRI plume predicts a weak and short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C. The latest North American Multi-Model Ensemble (NMME) forecasts are cooler than the IRI plume and predict a weak La Niña.  Due to this guidance and La Niña-like atmospheric circulation anomalies over the tropics, the team still favors the onset of La Niña, but it is likely to remain weak and have a shorter duration than other historical episodes.  A weak La Niña would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña is most likely to emerge in October-December 2024 (57% chance) and is expected to persist through January-March 2025).

Below is the middle paragraph from the discussion last month.

“The IRI plume predicts a weak and a short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C. The latest North American Multi-Model Ensemble (NMME) forecasts were warmer this month, but still predict a weak La Niña.  As a result of the warmer predictions and the recent weakening of equatorial trade winds, the team still favors a weak event, but has lowered the chances of La Niña.  A weaker La Niña implies that it would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña is favored to emerge in September-November (60% chance) and is expected to persist through January-March 2025).”

We now provide additional details.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. ASO  stands for August/September/October.

Here is the forecast from last month.

The analysis this month and last month are a bit different with again the transition to La Nina being slightly slower than thought last month. Also, the probabilities of a La Nina are lower than estimated last month. This seems to be a trend. The chart is clearer than the discussion in the summary report above.  The La Nina is a bit slower to arrive. I am not sure that we will actually have a La Nina.  However, one should read the Emily Becker article, which is discussed later in this article.

Some will need to click on “Read More” to read the rest of this article.

NOAA Updates its ENSO Alert on September 12, 2024 – We Remain in ENSO Neutral – Published September 14, 2024

September 14, 2024Posted inweatherNo Comments

“Synopsis: ” A weaker La Niña implies that it would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance”  

So we are really in ENSO Neutral but NOAA may not want to admit their forecast was wrong so they present it as waiting for La Nina. It is correct that we are in La Nina Watch but it is also correct that we currently remain in ENSO Neutral.

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 now describes their conclusion as “ENSO Alert System Status: La Nino Watch”

The exact timing of the transition is now perhaps more clear which should increase the reliability of the Seasonal Outlook to be issued next Thursday.

We have included an ENSO Blog article by Emily  Becker.

CLIMATE PREDICTION CENTER ENSO DISCUSSION (LINK)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The second paragraph is what is important:

“The IRI plume predicts a weak and a short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C (Fig. 6).  This month, the team relies more on the latest North American Multi-Model Ensemble (NMME) guidance, which predicts La Niña to emerge in the next couple of months and continue through the Northern Hemisphere winter.  The continuation of negative subsurface temperatures and enhanced low-level easterly wind anomalies supports the formation of a weak La Niña.  A weaker La Niña implies that it would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña is favored to emerge in September-November (71% chance) and is expected to persist through January-March 2025 (Fig. 7).”

Below is the middle paragraph from the discussion last month.

“The IRI plume indicates that Niño-3.4 is most likely to be below La Niña thresholds for four overlapping seasons, from September-November 2024 through December 2024 – February 2025.  Based on updated guidance and recent observations, the forecast team predicts nearly equal chances for ENSO-neutral and La Niña in August-October 2024, with higher odds for La Niña in September-November. Although the rate of SST cooling has been slower than previously anticipated, below-average subsurface temperatures and low-level easterly wind anomalies remain conducive to La Niña development in the coming months.  In summary, ENSO-neutral is expected to continue for the next several months, with La Niña favored to emerge during September-November (66% chance) and persist through the Northern Hemisphere winter 2024-25 (74% chance during November-January). “

We now provide additional details.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. ASO  stands for August/September/October.

Here is the forecast from last month.

The analysis this month and last month are a bit different with again the transition to La Nina being slightly slower than thought last month. This seems to be a trend. The chart is clearer than the discussion in the summary report above.  The La Nina is aa bit slower to arrive. I am not sure that we will actually have a La Nina.

Some will need to click on “Read More” to read the rest of this article.

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

May 10, 2024Posted inweatherNo 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

April 12, 2024Posted inweatherNo 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.

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:

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 March 14, 2024 – The El Nino Advisory/La Nina Watch Continues. Not Much Change on the Timing – Published March 15, 2024

March 15, 2024Posted inweatherNo 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.

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 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).”

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.  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).”

We now provide additional details.  The level of uncertainty with respect to how this El Nino will play out has not changed very much.

CPC Probability Distribution

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

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 January 11, 2024 – The El Nino Advisory Continues. Disagreement on When it Will End

January 12, 2024Posted inweatherNo 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”

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:

“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).

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 November 9, 2023 – The El Nino Advisory Continues. In a Week, NOAA Will Update us on how this Impacts U.S. Weather

November 10, 2023Posted inweatherNo 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”

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. That is concerning as some of the other Weather Advisory Organizations are predicting a higher probability for a “Historically Strong” El Nino.

We have included a link to an interesting ENSO Blog article by Emily Becker and a link to a fairly comprehensive article we wrote on El Nino back in September.  We have included some of the key graphics from both the Emily Becker Blog Post and the earlier article that I wrote and for those who have a strong interest in this El Nino winter, I recommend that you utilize the links to read both articles.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

” 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.”

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

“The most recent IRI plume favors El Niño to continue through the Northern Hemisphere spring 2024.  Also considering recent observations and the NMME, the team favors at least a “strong” event with a 75-85% chance through November-January (≥1.5C for the seasonal average in Niño-3.4).  There is a 3 in 10 chance of a “historically strong” event that rivals 2015-16 and 1997-98 (seasonal average ≥ 2.0C).  Stronger El Niño events increase the likelihood of El Niño-related climate anomalies, but do not necessarily equate to strong impacts locally.  Consider consulting CPC seasonal outlooks for probabilities of temperature and precipitation in the coming seasons.  In summary, El Niño is anticipated to continue through the Northern Hemisphere spring (with an 80% chance during March-May 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 MJJ 2024 and one does see a tail-off in the probabilities for El Nino conditions in the Eastern Pacific after the winter season.

Here is the forecast from late last month.

The analysis this month and last month are pretty similar.

NOAA Updates its ENSO Alert on October 12, 2023 – The El Nino Advisory Continues. In a Week, NOAA Will Update us on how this Impacts U.S. Weather

October 13, 2023Posted inweatherNo 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”

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. That is concerning as some of the other Weather Advisory Organizations are predicting a “Historically Strong” El Nino.

We have included an interesting ENSO Blog article by Emily Becker and a link to a fairly comprehensive article we wrote on El Nino back in September.

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume favors El Niño to continue through the Northern Hemisphere spring 2024.  Also considering recent observations and the NMME, the team favors at least a “strong” event with a 75-85% chance through November-January (≥1.5C for the seasonal average in Niño-3.4).  There is a 3 in 10 chance of a “historically strong” event that rivals 2015-16 and 1997-98 (seasonal average ≥ 2.0C).  Stronger El Niño events increase the likelihood of El Niño-related climate anomalies, but do not necessarily equate to strong impacts locally.  Consider consulting CPC seasonal outlooks for probabilities of temperature and precipitation in the coming seasons.  In summary, El Niño is anticipated to continue through the Northern Hemisphere spring (with an 80% chance during March-May 2024).”

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

“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 MJJ 2024 and one does see a tail-off in the probabilities for El Nino conditions in the Eastern Pacific after the winter season.

Here is the forecast from late last month.

The analysis this month and last month are pretty similar.

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

July 15, 2023Posted inweatherNo 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.