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April 2019 El Niño update: You are here

The Great Puny El Niño of 2018­–19 continued through March, and forecasters predict it will likely remain through the summer and possibly continue into the fall. The tropical Pacific Ocean shows El Niño’s fingerprint clearly, with warmer-than-average sea surface temperatures stretching across the equator.

Difference from average temperature, sea surface, March 2019

March 2019 sea surface temperature departure from the 1981-2010 average. Graphic by climate.gov; data from NOAA’s Environmental Visualization Lab.

Birds fly here

The El Niño atmospheric response was also apparent in March, with continued greater-than-average cloudiness and rain near the International Date Line. This is the weakened Walker Circulation pattern, due to more rising air than average over the central Pacific as the warmth of the ocean is transferred to the air above. Both the regular-flavor Southern Oscillation Index and the Equatorial Southern Oscillation Index were negative during March (-0.3 and -1.2, respectively), showing this continued atmospheric response.

We are also interested in the near-surface wind patterns, another critical component of the Walker Circulation, because these winds are how the atmosphere communicates with the ocean. The trade winds normally blow relatively steadily from east to west along the equator, keeping warm water piled up near Indonesia. When they are weaker than average, the ocean surface can warm, and the pile of warm water can begin to slosh to the east. During March, the trades were weakened, but this pattern was confined to a fairly small area of the western Pacific. (Remember this for a bit later when I get into the forecast.)

Fish swim here

El Niño’s signature warmer-than-average sea surface temperatures were solidly evident in March, with a monthly average of 0.9°C above average from ERSSTv5, our longest observation dataset. The January–March 3-month average from ERSSTv5, what we call the Oceanic Niño Index, was 0.8, marking the fifth consecutive, overlapping 3-month period above the El Niño threshold (0.5°C above average).

Monthly sea surface temperature Nino 3.4 Index Values, March 2019

Monthly sea surface temperature in the Niño 3.4 region of the tropical Pacific for 2018–19 (purple line) and all other El Niño years since 1950. Climate.gov graph based on ERSSTv5 temperature data.

The purple line above is noticeably flat, without the gradual increase, peak, and decline that so many other El Niño events have exhibited. This flatness isn’t unusual behavior for a weak El Niño, however, as other events, including 1977–78, 1978–79, and 2004–05, show.

Future you lives here

What is unusual is the model forecast for continued weak El Niño through the summer, with the tropical Pacific sea surface temperature expected to stay a bit above the El Niño threshold. This is a pattern that we haven’t seen in the (admittedly short) 1950–present historical record.

Also, forecasters think there’s about a 50-55% probability that El Niño will continue into the fall. As we’ve discussed before, the spring predictability barrier means it’s difficult for climate models to make successful predictions during March, April, and May, a time of year when ENSO (El Niño/Southern Oscillation, the entire El Niño and La Niña system) events are usually decaying and changing phase. This springtime indecisiveness partially explains the moderate probabilities that forecasters estimate for El Niño continuing into the fall.

The amount of warmer-than-average water between the surface and about 300 meters below the surface was elevated during March, as a downwelling Kelvin wave continued to move eastward under the surface of the equatorial Pacific. As this blob of warm water gradually rises, it will provide a source of warm water to the surface, helping to keep temperatures elevated through the next few months, and helping support the forecast through the spring and summer.

Temperature anomalies of subsurface temperatures in March

Departure from average of the surface and subsurface tropical Pacific sea temperature averaged over the 5-day period centered on April 3rd. The vertical axis is depth below the surface (meters) and the horizontal axis is longitude, from the western to eastern tropical Pacific. This cross-section is right along the equator. Climate.gov figure from CPC data.

The subsurface temperature in March, as well as the near-surface winds (see “birds” above), have some correspondence to ENSO conditions in the subsequent fall/winter, but not a super strong relationship. This 2015 post by Michelle gets into that relationship, showing that there has been a pretty wide range of outcomes in the historical record. (That post uses an older sea surface temperature dataset, but the results would be similar using the newer one.) So while these conditions are factored in to the forecast for the later part of the year, they’re not a huge source of confidence. Plus, the wind anomalies in the western Pacific are pretty darn feeble, which does not elicit comparisons with the evolution leading up to the major 2015-16 El Niño. 

Since ENSO interacts with the hurricane season, I’ll be interested to see how the forecast for continued weak El Niño affects the Climate Prediction Center’s hurricane outlook, issued later next month. For now, stay tuned, and we’ll keep you updated on all things ENSO!

Comments

Nice and clear post! Could be possible to update figures of 2015 post by Michelle L'Heureux (https://www.climate.gov/news-features/blogs/enso/d%C3%A9j%C3%A0-vu-el-ni%C3%B1o-take-two), including last years, specially 2015.

The nice thing about linear regression is that it (the red line) doesn't change much w/ the addition of new data. The general principles still hold.  Right now the low level winds look like this:

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/uv850-30d.gif

And the heat content looks like this:

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/weeklyenso_clim_81-10/wkteq_xz.gif

Which are some reasons we're not, at this point, expecting a particularly significant El Nino if it were to continue (not like 2015-16 which was a top three event).   

In reply to by Leandro B. Díaz

not a science person, but situation very real for me. when you write "we're not, at this point, expecting..." you mean for 2019? or as far out as you can see? or is as far out as you can see, or anyone can see, only 2019 anyways? in other words, what you cited, does or does not rule out 2020 being just as bad as 2015? because that is a very serious question, even a year ahead of that.

In reply to by michelle.lheureux

Yes, we are specifically talking about 2019 to early 2020.  And yes, that is about as far out as we can see with reasonable skill.  At this point, we cannot rule out anything for later in 2020.  However, I will mention that we have not experienced a three-year El Nino in the historical record, so if we continue to experience El Nino conditions through fall 2019 and early winter 2020, then it would seem to be very unlikely that we would experience an El Nino like 2015/16 the following year. 

In reply to by Steven Stoffers

Off of southern CA we've noticed cooler than average near shore water temps than usual for this time of year...usually warming by now. That strip of cooler water that pushes up against southern CA; is that the Walker Circulation you mentioned and do you think conditions will give way for that warmer water down Mexico way to make its way north as summer progresses?

In reply to by michelle.lheureux

That region is too far north to be directly affected by the Walker circulation.  Most of the ocean surface off California seems to have warmer than average temperatures (see, for example, here), so I am guessing that the cooler waters reflect local wind conditions and the ocean response.  On the larger scale, the forecast models generally have been favoring warmer than average conditions along the California coast, so I would not rule out a reversal of the cooler conditions you describe.  

In reply to by Bruce Hershberger

El Niño 2018-20 = El Niño 1986-88 Peak El Niño 86- 87 - December 86 Peak El Niño 87-88 - August 87 Peak El Niño 18-19 - December 18 Peak El Niño 19-20 (forecast) - June 19 Details in NMME ENSO e Models (ECMWF, UKMO, BOM , JMA) at Climate Model Summary of Australia.

I look forward to your blog every month it’s unbiased and clear interpretation of actual weather measurements ,keep up the good work.regards Ray

Much appreciated!  Emily does do an awesome job w/ these top of the month posts, that's for sure.   

In reply to by Ray Zahra

Very nice writing and explanations. How can you tell whether the warming is due to a Kelvin wave or the warming is due to something else like lack of upwelling? Is it the size of the anomaly? Thanks,Jeff B.

The warming impacts from downwelling Kelvin waves are not instantaneous so we can track their journey across the Pacific Ocean. From there, we can time when its influence might begin to show up in the metrics we use to measure ENSO.  A lack of upwelling and a weakening of the trade winds can also cause surface warming too and also can be monitored through buoys in realtime. Oftentimes, you might see both occurring at the same time.

The temperature cross-section of this looks a lot like the one you showed us in your April 12, 2018 post. This time is it a whale shark instead of a great white?

Thank you all for a very readable article! I now think that I now better understand the importance of the ENSO work and the effects of the phenomena on our weather. Ms Becker, thank you for your excellent, clear writing.

I visit Christmas Island twice a year for fishing, so I value tremendously the analysis that you provide. Even if it’s not always what I want to hear.

I presume that all the observations relating to coral destruction in this article were made outside the atoll. Would I be correct in asserting that the extent and pace of destruction inside the atoll is even more pronounced because the water is much shallower there and the coral therefore more susceptible to temperature swings?

In reply to by tom.diliberto

I am in agriculture in Australia and use historical STT supplied by NOAA to tie in with actual rainfall received on my property for that period. The current pattern actual and forecast looks like that of mid 1986 to early 1988 where an El Niño started in late 86 contued right through 87 and ended in 88. This resulted in 30% of ave rainfall for both 86&87 and 120% for 88. In you update you state this pattern has not happened since 1950 . Are the two patterns the same or am I on wrong track.

Hi Lachlan,

To clarify, I meant that the forecast pattern, which predicts the Nino3.4 SST will remain between 0.5 and 1 degree above average through next winter, is not something we've seen before. You're right that the current pattern resembles the first part of 1986-88, through spring 1987, when the SST anomaly started to increase, eventually peaking at 1.7 degrees above average in July-September.

The weather has definitely been strange this year. There are many older weather forecasters that understood the El niño a lot better than computer models but they are retiring. I don't think the commercial phone apps understand it. Still waiting for the tropical depressions to start forming in the eastern Atlantic but the El Niño may have brought a pattern change to the east coast in the US. The hurricane cycle of 20 years may have an effect this year, will see if it holds true. There are some that would like to see NOAA privatized.

hello all, im coming over from england. how does a weak el nino affect may grey/june gloom?

Generally, we would expect fewer May Gray/June Gloom days with an El Nino episode, but I would not expect a strong impact with the weak episode that we currently have.  

In reply to by gary greenslade

During the wet season (May-Nov) El Nino's impact tends to be drier than average in the DR.  A great webpage for seeing the probability for below/near/above precipitation is located here courtesy of the IRI and suggests 2019 may lean dry:

https://iri.columbia.edu/our-expertise/climate/forecasts/seasonal-climate-forecasts/

At this point it's too early to say how 2020 will be impacted based on the state of ENSO.  

Is it possible that a La Nina could develop into late or early December if possible?

Has the release of the ENSO information you referred to in your May 3rd reply changed any effect that El Nino will have on the 2019 Atlantic Hurricane Season? Thanks for your research. Bob

Living here in California, I will never forget how El Nino was such a threat a couple of years ago. That was the BIG weather topic all fall prior to January. Then, when the first forecast in January was predicted the meteorologists stated...Here it comes! Sandbagging began full speed ahead! Then.....nothing. It was crazy. We had no rain. Very very little all that season. So now, we don't hear anything about it. Last year I totally thought we had one, but they called it an atmospheric river. No mention of El Nino. I think they are afraid to mention it. So we are of course curious when the ocean temperatures are warmer than ever before! So, is it still too early to state whether or not to expect an El Nino ???

Atmospheric rivers are driven by various weather and climate phenomena and are not always related to ENSO.  El Nino can help increase the occurrence of them, but that is, by no means, guaranteed.  Our ENSO outlooks are probabilistic and each month we offer updated chances for an El Nino event, which we also discuss here on the ENSO blog.  https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

In reply to by Marcia

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