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 February 8, 2024 – The El Nino Advisory Continues. The La Nina Watch Begins – Timing of the Transition is Uncertain

February 9, 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 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:

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

What about El Nino? September 23, 2023

September 23, 2023Posted inClimate, 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 it’s Four-Season Outlook On February 16, 2023 – Potential El Niño impacts were considered in the outlooks for autumn 2023 and next winter

February 17, 2023Posted inweatherNo Comments

Updated at 3:05 p.m. EST February 17, 2023 to incorporate information on the latest Sudden Stratospheric Warming (SSW) event

On the third Thursday of the month right on schedule NOAA issued what I describe as their Four-Season Outlook. The information released also included the MId-Month Outlook for the single month of March plus the weather and drought outlook for the next three months.  I present the information issued and try to add context to it. It is quite a challenge for NOAA to address the subsequent month, the subsequent three-month period as well as successive three-month periods for a year or a bit more.

It is very useful to read the excellent discussion that NOAA issues with this Seasonal Outlook. The CPC/IRI analysis suggests that ENSO will very soon return to Neutral with a La Nino bias and gradually transition to true Neutral, Neutral with an El Nino bias, and then solidly El Nino. Confidence in the first part of that sequence of transitions is higher than in the latter part of the sequence.

NOAA Updates it’s ENSO Outlook on February 9, 2023 – Changes are Coming

February 10, 2023Posted inweatherNo Comments

Updated at 3:23 p.m. EST Friday, February 10 to include a second interesting ENSO Blog Article. You have to click where shown to read them.

On the second Thursday of every month, NOAA issues its analysis of the status of ENSO. This includes determining the Alert System Status. The best guess remains March.

This may seem like a repeat of our article from last month and in a way it is since the situation has not changed. But no change increases the confidence in the forecast.

And again some of the models suggest a rapid change to El Nino. It seems likely that the ENSO Neutral Phase will at the very least have an El Nino bias.

Because the situation has not changed, we have published a shorter version of our usual article since there is little disagreement that we are transitioning away from La Nina. It is also a bit too early to examine the potential for an El Nino. We need to get past the Spring Prediction Barrier (SPB) to be confident about having an El Nino soon.

The article includes two very interesting posts from the ENSO Blog. They are worth reading.

NOAA Updates it’s ENSO Outlook on January 12, 2023

January 14, 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. The best guess remains March.

But I have actually seen only a few signs of it starting to happen. But all the meteorologists agree that it will.  Could they all be wrong? Probably not.

Will this La Nina transition quickly to the El Nino phase? That would be unusual but some of the models suggest this will happen.  It seems likely that the ENSO Neutral Phase will at the very least have an El Nino Bias.

NOAA Updates it’s ENSO Outlook on December 8, 2022

December 9, 2022Posted inweatherNo Comments

Updated at 3:45 p.m. December 9, 2022 to complete certain edits that were not completed at the time this article was published. They add a little more clarity to the discussion.

On the second Thursday of every month, NOAA issues its analysis of the status of ENSO. This includes determining the Alert System Status. Although the current status remains the same i.e.  La Nina Advisory, the forecast has again been adjusted slightly from the prior month. There is some disagreement on when this La Nina will end with the best guess being perhaps March. But some meteorological agencies believe it could be sooner than that.

But I have actually seen only a few signs of it starting to happen. But all the meteorologists agree that it will.  Could they all be wrong? Probably not.

Will this La Nina transition quickly to the El Nino phase? That would be unusual but some of the models suggest this will happen.

NOAA Updates its Four Season Outlook on November 17, 2022 – La Nina Winter then Big Changes

November 18, 2022Posted inweatherNo Comments

La Nina Winter, then ENSO Neutral and Then Maybe Something Else

Today is the third Thursday of the month so right on schedule NOAA has issued what I describe as their Four-Season Outlook. The information released also includes the MId-Month Outlook for the single month of December plus the weather and drought outlook for the next three months.  I present the information issued and try to add context to it. It is quite a challenge for NOAA to address the subsequent month, the subsequent three-month period as well as successive three-month periods for a year or a bit more.

We will begin to see the end of La Nina Impacts in March/April/May of 2023 and they will pretty much end before June/July/August of 2023, and there will be another change in November/December/January 2023/2024. Why that last change? Could it be an El Nino or ENSO Neutral with an El Nino Bias?

It is very useful to read the excellent discussion that NOAA issues with this Seasonal Outlook. NOAA seems to be more confident about making predictions beyond six months. They even predict a good Southwest Monsoon next summer which they never used to do this far in advance.

NOAA Updates it’s November 2022 ENSO Outlook

November 14, 2022Posted 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. Although the current status remains the same i.e.  La Nina Advisory, the forecast has again been adjusted slightly from the prior month. There is some disagreement on when this La Nina will end with the best guess being perhaps March.

But I have actually seen only a few signs of it starting to happen. But all the meteorologists agree that it will.  Could they all be wrong? Probably not.