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November El Niño update: It’s a small world

The peak of our current El Niño is expected to occur in the next month or so… but what does that mean? We measure El Niño events by how much warmer the surface waters in a specific region of the equatorial Pacific are, compared to their long-term average. The difference from average is known as the “anomaly,” and we use the average anomaly in the Niño3.4 region as our primary index for El Niño. When the index in this region is at its highest, we have our peak El Niño.

Sea surface temperature anomaly map

Average sea surface temperature departure from the 1981-2010 average over the four weeks ending on November 7. Graphic by climate.gov, data from NCEP-NCAR reanalysis.

 

However, El Niño-related impacts have been occurring around the globe for months already, and will continue for several months after the warmest temperatures occur in the tropical Pacific Ocean. For example, during the 1997-98 El Niño, the Niño3.4 Index peaked at 2.33°C in November (using ERSSTv4 data, the official dataset for measuring El Niño), and the most substantial U.S. effects occurred through the early spring of 1998. A bit later in this post, we’ll take a look at what’s been going on so far this year.

 

First, a quick update on the recent El Niño indicators

The average anomaly in the Niño3.4 region during August-October of this year was 1.7°C, second to the same period in 1997 (1).

SST ranking graph

Ranking of August-October average sea surface temperature departures from the mean for all El Niño episodes since 1950. This measurement, the Oceanic Niño Index, uses ERSSTv4 data. Figure by climate.gov, data from CPC.

 

The atmospheric response to the warmer waters is going strong. The Walker Circulation (tropical near-surface winds blowing from east to west, and upper-level winds blowing from west to east) is substantially weakened, as we expect during a strong El Niño.

Near-surface wind anomaly maps

Top: Recent departure from the 30-year average near-surface winds. Purple shading area indicates where the normally easterly (blowing from east to west) winds are weaker than normal. Bottom: Recent departure from the 30-year average upper-level winds in the tropical Pacific region. Purple shading area indicates where the normally westerly (blowing from west to east) winds are weaker than normal. Maps by climate.gov, data from NCEP-NCAR reanalysis.

 

In case you’re unimpressed by a 2°C (3.6°F) change, let’s do a little math. The area covered by the Niño3.4 region is a little more than 6 million square kilometers (2.4 million square miles). One cubic meter of water weighs 1,000 kg. So the top two meters (6.6 feet) of the Niño3.4 region contains about 12 quadrillion kilograms (about 13.6 trillion tons) of water.

The energy required to raise one kilogram of water one degree Celsius (the “specific heat”) is 4.19 kilojoules. A 2°C increase in just the top two meters of the Niño3.4 region adds up to an extra 100 quadrillion kilojoules (95 quadrillion BTUs), about equal to the annual energy consumption of the U.S.!

Who’s feeling the effects?

In the U.S., the season of strongest El Niño impacts is December through March. While we’re waiting to see what the strong 2015-16 El Niño brings us, we’ll look around a few other corners of the world to see what’s happened so far.

El Niño has substantial impacts in two regions of Africa. I checked in with the Climate Prediction Center’s International Desk to see what’s been going on. In East Africa, including Ethiopia, Somalia, Kenya, Tanzania, Uganda, Burundi, and Rwanda, the primary impact season is October–December, when El Niño tends to enhance the ”short rains” rainy season (the “long rains” season, which is much less ENSO-sensitive, is March-May), leading to wetter conditions. Over the last month, rain has begun to increase across much of the area, and some flooding has been seen in Somalia. Short-term forecasts suggest the wetter conditions should continue through the next few weeks, at least.

Precipitation anomaly map

Monthly precipitation departure from the long-term average during October 2015. Map by climate.gov, data from the CPC ARC2. 

 

Southern Africa, including Zimbabwe, Botswana, Namibia, Angola, South Africa, Lesotho, Swaziland, and the southern half of Mozambique, tends to see a drier December–February during an El Niño. Areas of this region, especially South Africa, are very dry right now, after a failed monsoon last year. Another dry year would place more stress on water availability. You can check out recent rainfall conditions in Africa here, and see climate model forecasts for the continent here.

In a couple of short sentences, here are some huge impacts: El Niño-related dry conditions in Indonesia have set the stage for devastating fires, and the region is experiencing the greatest number of forest fires since 1997. Also, all the extra warm waters associated with this El Niño are placing heat stress on sea life, and an intense coral bleaching event is underway.

El Niños tend to enhance the hurricane season in the Pacific, and depress the Atlantic hurricane season. Phil Klotzbach of Colorado State University had this to say about the wild Pacific hurricane season: “So far this year, there have been a total of 21 Category 4 and 5 storms in the North Pacific, shattering the old record of 17, set in 1997.  The North Central Pacific region (140-180W) has shattered records for most named storms, hurricanes, and major hurricanes tracking through the 140-180W region.”

According to Lindsey Long of the Climate Prediction Center, the Atlantic season has been fairly quiet, although the number of named storms has been close to average, at 11 storms so far (including Kate, which formed on Monday). The average is about 12… but the overall activity of this storm season (the combined strength and duration of all storms, measured as the Accumulated Cyclone Energy (ACE) has been less than 60% of average, and we’ve had 3 hurricanes, half the average number of 6.

We won’t know until next spring what exact impact this El Niño will have on the U.S., but it is already making its presence felt around the world.

(1) Note that CPC subtracts past 30-year “normals” from the current sea surface value to obtain the Nino-3.4 anomaly values, and the “normals” are updated every five years. Therefore, the long-term trends are removed.  These monthly values are averaged together to obtain our Oceanic Niño Index [ONI].

 

Comments

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Generally speaking the more rain the less crime in California. Heat and dryness brings out more reports of domestic violence, DUI, Murders, and Assault type cases.

Submitted by criminal defense on Thu, 11/12/2015 - 23:17

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Great article...very informative (as opposed to main-stream media drivel) Thanks!

Submitted by Rob G on Fri, 11/13/2015 - 00:19

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Thank you for the article Emily, it was educating and easy to follow. I enjoy it when people can break down data for the general public. I would have loved to see the data in the Ranking of August-October El Nino Episodes graph in consecutive order by year. It makes me curious to see what kind of trends may be occurring over a greater period of time. (i.e. every 20 or 100 years). Good work.

Submitted by Amber Forest on Fri, 11/13/2015 - 08:56

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Who has picked up the work of Joseph Fletcher after he left NOAA in 1993. What are you seeing in the wind strength around the world. Are you following it along with the sun intensity? Is COADs still being generated? Thanks!

Submitted by larry wilhelmsen on Fri, 11/13/2015 - 16:28

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Wow, you really go back a long way, talking about Joe Fletcher. MANY scientists have picked up where he left off. To name just a small subset: Gene Rasmussion, Mark Cane, Steve Zebiak, Max Suarez, Paul Schopf, Mike McPhaden, Chet Ropelewski, Tim Barnett, Kevin Trenberth, Mojib Latif, Ants Leetmaa, Ming Ji, Arun Kumar, Marty Hoerling, Tim Stockdale, Tim Palmer. I'm sure I'm omitting some others. I guess by "wind strength around the world", you're referring to the angular momentum studied by Rick Rosen, am I right? And during ENSO there is a perturbation in it. Sun intensity? How do you relate that (e.g., the 11-year cycle) to ENSO? COADS? Are you back in the 1990s still? Yes, we still use ship and buoy SST observations, and combine them with satellite measurements for some of the current SST data sets. You should check out the ERSST data set and the OISST data set. A lot has been going on since the 1990s!

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Some amazing information that I have never even about. The amount of energy that goes into a strong El Niño event like this is hard to comprehend.

Submitted by Ben on Fri, 11/13/2015 - 17:47

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This gives me one up on all those people who get their weather from TV. I try to tell them, 'Everybody gets their weather from NOAA.'

Submitted by Peter on Sat, 11/14/2015 - 08:23

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You are absolutely correct. I have been using the NWS, NHC, WPC, SPC and CPC products for many, many years and by far it is the most accurate weather data you can get. Most of the TV and other Internet sites are usually way off target. Being living close to KCXO we see a a lot of fast changing weather patterns. I have been known to be the local weathman in the area. I will tell them and give the site address. Could tell you more about this topic at another time.

Submitted by Tom F. on Sat, 11/21/2015 - 05:23

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I concur. NOAA's products are the real deal. I also blindly suspect they outshine most other National earth science bureaus. I've been visiting them online daily since I was 13 (almost 20 years)... Theyre systematic, methodical and consistent in their delivery!

Submitted by Sherman on Mon, 11/30/2015 - 12:08

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Emily, The news media in Florida has reported that an effect of El Nino in 2016 will be worse than average winter weather and storms. If true, is this linked to less than average hurricane season for Florida for the El Nino year?

Submitted by Alan on Sun, 11/15/2015 - 22:17

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Yes, in a strong El Nino such as this one, Florida is expected to have above average winter rainfall, and some of the rain may come with storminess in terms of wind, but nothing dangerous. Besides giving Florida a wet winter, El Nino usually also results in a quieter hurricane season in the preceding summer and fall, and that is indeed what has been observed during the last several months. El Nino's effects on both the effect on hurricanes and on Florida's winter rainfall have known physical causes.

Submitted by anthony.barnston on Mon, 11/16/2015 - 13:25

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During winter and early spring (next 5 months), the usual effect of El Nino on southeastern Caribbean region is for below average rainfall. That region shares its impact with northern South America. It is the opposite effect from the above average rainfall expected in the northern Caribbean and southeastern US. After mid-spring, effects are unknown, partly because the El Nino is expected to dissipate around that time.

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Use the NOAA products NHC which does more than just track hurricanes and has weather forecasts and discussions for the area in question and the NOAA marine products as well. Remember that the longitudes in their discussions is not correct. All longitudes west of longitude 0 will need a minus sign appended to its location. NOAA has never corrected this for 20 years. East of longitude 0 is positive. Latitude also has this error to. North of the equator, lat 0 is positive and south of the equator is negative.

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Great article update! I see two major El Nino hot spots and one is aiming towards the CA coastline. Can you give us a prediction/forecast of rainfall and timing for this winter? We're worried about flooding as in 1982-1983 and 1996-1997. Accu-weather shows hardly any rain predicted for my area through December 2015. Thanks.

Submitted by Melinda on Mon, 11/16/2015 - 14:00

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Believe you mean 1997/98, but I know what you mean.  As far as timing rainfall into California, that's really beyond the state of the science.  The current oulooks for the rest of November and December are equal chances, which means there's no strong signal or tilt in the odds for wetter or drier than normal weather.  However, the lack of significant rainfall during the early part of the winter is not unusual with El Nino, as the best chance for above normal rainfall is typically during the January - March season.

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There's no way to convert between the weekly OISST value and the seasonal ONI value, since they use different underlying data sets.  For the past few months, the data set used for the ONI (ERSST) has been running a bit more than 0.5C cooler than the OISST.  You can read more about the different data sets in this blog post:

https://www.climate.gov/news-features/blogs/enso/exactly-same-completel…

 

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Hello addition As well as 2 the form of Hurricane strongly 4 and 3 in the Gulf of Aden in the Arabian Sea is the first of its kind

Submitted by Mr. Khalid on Tue, 11/17/2015 - 13:26

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Hi, can you please elaborate on the implications in the Peru area, please?

Submitted by Ionut Ciuca on Thu, 11/19/2015 - 04:43

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Great article, thanks. Can you give any insight into what El Nino might mean for us on the Central Coast this winter. We're trying to plan ahead for flooding and our weather charts don't go far enough ahead to predict. Any help would be greatly appreciated.

Submitted by Melinda R. on Thu, 11/19/2015 - 14:37

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The current seasonal forecasts have a tilt toward above normal rainfall during both the December - February and January - March seasons.  There's not much else we can say at this time, although it's worth remembering that during the other two strongest events (1982/83 and 1997/98) there were numerous signifcant storms with much above normal preciptiation, particularly from the middle of the winter into the beginning of the spring.

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Business Insider illustrates an upcoming La Niña in 2016 based on model outputs. Please explain the possibility of the cold episode in 2016, or it is simply an over-prediction in the case.

Submitted by Peter Pan on Thu, 11/19/2015 - 16:23

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While we currently expect this El Nino to transition to neutral by next summer, what comes next is still an open question.  It's really just too far into the future to make a prediction that would be anything except a guess.  The 1997/98 did quickly transition to a La Nina, but the Pacific ocean after the 1982/83 event only became marginally below average and the La Nino didn't develop until the following winter (1984/85). 

Submitted by mike.halpert on Sun, 11/22/2015 - 20:04

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Is there any information if there is going to be La niña after el niño? What can be expected after el niño?

Submitted by Juan on Fri, 11/20/2015 - 10:30

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Emily's simple calculation of the energy potential in a strong El Niño crystallized, at least for me, how a small change in temperature in a relatively small, but strategic area of the world can have such a global impact. Her clear style, measured tone and data driven explanation is a breath of fresh air in a storm of media hype. Should be required reading.

Submitted by Kim Anderson on Sat, 11/21/2015 - 16:55

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Currently living in Thailand and want to know the effects of El Nino for the coming year. Monsoons were late this year. I am predicting a dry year. Am I correct in this?

Submitted by Larry on Sun, 11/22/2015 - 22:36

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Reading Emily's great article and her explanation of the energy needed to warm the Nino 3.4 Region, the question came up of what exactly is meant by "sea surface temperature" (SST) when talking of ONI. Is it the the upper two metres which she mentions?

Submitted by Kurt on Mon, 11/23/2015 - 13:55

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Great question... I'm not an expert on this topic, but my understanding is that different observing systems (ships, buoys, etc) do measure "SST" at slightly different depths.   Almost all do so within the upper several meters of the ocean, but depths can vary.  When putting together SST datasets, the experts do account for this at least implicitly by adjusting the various types of observing systems so they are more consistent. 

Submitted by michelle.lheureux on Mon, 11/30/2015 - 14:53

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It's been a bust so far in Southern California, except for some tropical rain in August and September. Hopefully El Niño will deliver in the December thru April time period. If I recall 82/23, 92/93 and 97/98 had wet midwinters and springs also. What is your outlook for specifically Southern California and the coastal areas?

Submitted by Eddie on Mon, 11/23/2015 - 18:23

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Too early to call it a bust given that the higher chances for precipitation are not until the core winter months.  Best chances are January-March.  Also, keep in mind that there are no guarantees in seasonal climate outlooks.... our forecasts state there are increased odds (%) for precipitation, but certainly not assured.  See CPC's latest outlooks here:  http://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=1

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Thank you for the update on the niño. What do you think of the effects on South America?

Submitted by Gaby on Tue, 11/24/2015 - 06:27

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Hi Emily, thanks for the detailed information and your hard work. I noticed that the Galapagos wasn't on the radar for "Who's feeling the effects?" Sorry, to make this personal, but my family and I were thinking of visiting the Galapagos over the holidays and were wondering what effects El Nino may display there. Many of the locals in Ecuador say nothing will happen, while others say the warmer waters will cause the plankton to migrate in search of cooler water and that the food chain will follow. This of course will greatly affect the opportunity to see wildlife in a costly trip. If you have any info if this is currently happening or no where I could find out, that would be much appreciated. All the best. Ed

Submitted by Ed Millis on Wed, 11/25/2015 - 22:37

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We were in Galapagos in late November, and will return mid december. I was impressed with a few things: VERY strong trade winds, and cool waters only two metres + below the sea surface. This is very unusual for "normal" Novembers. The water is warm, indeed, but the sea is showing much prodcutivity. In North seymour, boobies where not only continuing with their reproductive effords late november, but even some couples where courting. As an oportunistic breeding species, this is very strange. All in all, we had a great time! Fantastic encounters with wildlife, inlcuding orkas and dolphins. It seems the strong winds are allowing upwellings to rise despite El Niño

Submitted by Peter on Tue, 12/08/2015 - 09:33

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Dear Ms. Becker and colleagues, Thank you for the clear explanations and diagrams, and thank you for the links to South American forecasts (Columbia and Instituto del Mar), neither of which would be useful without your analysis.

Submitted by JH JP on Sat, 12/12/2015 - 16:52

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