NOAA Updates It’s ENSO Alert Status on January 9, 2025 – La Nina Has Finally Arrived They Say – Published on January 11, 2025

January 11, 2025Posted inweatherNo Comments

“Synopsis:   “La Niña conditions are present and are expected to persist through February-April 2025 (59% chance), with a transition to ENSO-neutral likely during March-May 2025 (60% chance). “

So we are no longer in ENSO Neutral but officially in La Nina (but we may not stay in La Nina long enough for it to be recorded as an official La Nina for historical purposes.)

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 Nina”

It should increase the reliability of the Seasonal Outlook to be issued next Thursday. But will it?

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 La Niña during the winter seasons, as indicated by the Niño-3.4 index values less than -0.5°C . The North American Multi-Model Ensemble (NMME) predicts slightly cooler SST anomalies with La Niña persisting through February-April 2025.  The forecast team favors the NMME guidance, predicting weak La Niña conditions through the early spring before transitioning to ENSO-neutral.  Weak La Niña conditions are less likely to result in conventional winter/spring impacts, though predictable signals can still influence the forecast guidance (e.g., CPC’s seasonal outlooks).  In summary, La Niña conditions are present and are expected to persist through February-April 2025 (59% chance), with a transition to ENSO-neutral likely during March-May 2025 (60% chance).  ”

Below is the middle paragraph from the discussion last month.

“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).”

{Author’s Note: Has anything really changed?]

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 fairly similar.  But a future El Nino is a bit more in the picture.

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

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

September 15, 2023Posted inClimate, weatherNo 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.

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.