What is a super El Nino?

 I and most weather outlets have been talking about the developing El Nino. I have gotten a number private and public post and comments wondering about the impacts of the developing El Nino will have on our summer weather.  I’ve seen several media outlets suggest that El Nino will cause enhanced heatwaves around the world. In my hurricane and summer outlooks I talked about El Nino. I even said this year’s El Nino will be very strong and could even become a so called Super El Nino. With all the talk about this, some of y’all are a bit worried. 

So I thought this might help clear something up.

What is El Nino? …

The ENSO is a natural phenomenon that results from the coupled interactions between the tropical Pacific and the atmosphere. The changing sea surface temperatures (SST) alter rainfall, ocean currents, and wind patterns around the globe. All of this produces a positive feedback loop, which leads to even more changes.

El Nino is linked to major changes in the atmosphere known as the Southern Oscillation (SO). El Nino’s sibling is called La Nina. Both of these are encompassed by what is called the El Nino–Southern Oscillation (ENSO).  El Nino is the warmer phase, with La Nina being the cooler phase.

El Ninos generally occurs every three to seven years or so, the surface waters of the equatorial Pacific Ocean become extremely warm from the International Dateline to the west coast of South America.

SST anomaly 2023.

There are several indices used to monitor the tropical Pacific, all of which are based on SST anomalies averaged across a given region.  Usually, the anomalies are computed relative to a base period of 30 years.  The Nino 3.4 index and the Oceanic Nino Index (ONI) are the most commonly used indices to define El Nino and La Nina events.  Other indices are used to help characterize the unique nature of each event.

 

The numbers of the Nino 1,2,3, and 4 regions correspond with the labels assigned to ship tracks that crossed these regions over the last 100 years. While humans discovered El Nino during the last 100 to 150 years, the global historical record shows that the ENSO has been around for millennia.

The Nino 1+2 region is the smallest and eastern-most of the Nino SST regions. Normally, this index tends to have the largest variance of the Nino SST indices.

The Nino 3 region used to be where SST were monitored and were used in predicting El Nino, but researchers later learned that Nino region was too far east to get a true measurement for coupled ocean-atmosphere interactions when it came to defining El Nino and La Nina events.

The Nino 3.4 is now the area thought of as representing the average equatorial SST anomalies across the Pacific. The Nino 3.4 index typically uses a 5-month running mean, and El Niño or La Nina events are defined when the Nino 3.4 SSTs exceed +/- 0.4C for a period of six months or more. This is closely linked to the ONI. The ONI uses a 3-month running mean, and to be classified as a full-fledged El Niño or La Niña, the anomalies must exceed +0.5C or -0.5C for at least five consecutive months inside Nino region 3.4.

The Nino 4 index captures SST anomalies in the central equatorial Pacific.  This region tends to have less variance than the other Nino regions.

To define the distinctive character of each El Nino or La Nina event, a combination index, called the Trans-Nino Index (TNI) is used.  The TNI is defined to be the difference in normalized SST anomalies between the Nino 1+2 and Nino 4 regions.  The TNI thus measures the gradient in SST anomalies between the central and eastern equatorial Pacific.  When the SST gradient is particularly large (say, due to very warm SST anomalies in the Nino 4 region and somewhat cooler SST anomalies in the Nino 1+2 region, this is classified as a central Pacific El Nino or sometimes called El Nino Modoki.

NOAA declares an official El Nino has developed when sea-surface temperatures in Nino region 3.4 have reached at least 0.5 degrees Celsius above average for at least a month and is expected to persist for several more months.

One important thing to remember is Every El Nino cycle is different.

OK what about this year…

Over the past three years, Nino regions 1+2 to 4 have been cooler than average. So, we’ve been in a three year La Nina, which is often called a triple dip La Nina. But that ended by March of this year , and water temperatures have quickly been getting warmer since then. So currently the ENSO is in a neutral phase. Right now, anomalies are such that we’re on the cusp of El Nino. This means El Nino very well could develop sometime this summer, and that could have impacts on our summer weather here in the Northeast, and in the upcoming hurricane season. Since El Nino and La Nina events typically exert the most influence on the late Fall and winter. It could have a big impact on winter 2023-2024.

Some models are raising the possibility later this year of an extreme, or super El Nino, that is marked by very high temperatures in the Nino 3.4 region.

OK, what is a super El Nino? …

The term super El Nino is used to describe a very strong El Nino event.

Typically, when it comes to defining an El Ninos strength, anomalies of 0.5C to 1.0C above average is considered weak, anomalies 1.0C to 1.5 above average is considered moderate, with anomalies of 1.5C to 2.0C above average considered strong. Super El Ninos feature anomaly temperatures that are greater than 2C above average.

Officially there had only been three super El Ninos – 1982 to 83, 1997 to 98, and 2015 to 16. Some meteorologist also considered the El Nino in 1972 to 1973 as an extreme event.

El Nino and a warming Planet…

Typically, during an El Nino, overall temperatures around the globe, increase. During a super El Nino there can be an even large increase.

A few years ago, Joe Bastardi posted on how Super El Nino’s seem to set a new plateau in regards to warming global temperatures. I had never thought of that idea before. I don’t know if it was Bastardi or someone else who came up with the idea; but I found it fascinating and insightful. 

When we look at the UAH global temperature chart by Roy W. Spencer, Ph.D., a research scientist at the University of Alabama, Huntsville, we see that the globe is warming. When we place the years of the Super El Nino on the chart, the plateauing stands out very clear.

A warming planet does interact and aggravate the effects of El Nino.  So, it’s certainly possible we will see 2023 break the record warm year set in the last Super El Nino in 2016.

How El Nino could impact the summer pattern…

Even though the impacts of El Nino are greater during the winter, that doesn’t mean there’re no influences during the summer.

How much impact the CONUS experiences is dependent on the strength of the El Nino event.  But generally, the CONUS sees cooler than average summer temperatures and slightly less than average precipitation in the eastern half of the country during El Nino.

Here is temperature and precipitation anomaly maps that show El Nino influence based on the strength of the El Nino.   

 

These maps don’t show the influence from a super El Nino on our temperatures for the Northeast and Middle Atlantic. So, I entered the data for the super El Nino’s of 1982 to 83, 1997 to 98, and 2015 to 16.

Because some meteorologist including me also consider the El Nino in 1972 to 1973 as a super El Nino; I’ve including that as well.

As far as the upcoming winter here in the Northeast, a super El Nino could mean overall temperatures for Dec thru Feb being well above average, with a general lack of snowfall across the region. 

The idea of a super El Nino was one of the major factors I used when I came up with my Summer Outlook, which you can find here. The super El Nino also figured into my hurricane outlook for this year; but even though El Nino’s typically led to fewer numbers of tropical cyclones in the Atlantic Basin; other factors such as all the warm water in the Atlantic, hint at higher numbers than would normally be the case during an El Nino event. If you what to look at the three-part hurricane outlook you can find it here.

 

Well, that’s it. I hope this cleared up any questions or confusion you had in regards to the likely very strong/super El Nino that looks to form this year.

 

2023 Atlantic Hurricane Outlook Part Three

 

The 2023 Atlantic Hurricane Season is right around the corner Which is why I’ve been talking about the tropics on my Facebook weather pages. I’ve also released part one and part two of the outlook for 2023.

These previous segments covered things like terms that I will use during the season; They also laid the ground work for Part 3.

Part one can be found here and Part two can be found here.

In my final installment of hurricane outlook series. I will go more into El Nino. More analysis of Sea Surface Temperatures, Make some adjustments to analogues. Take a look at my latest thoughts on the numbers and impacts they could bring. Talk about the Bermuda High, Reexamine the potential hot spots, I will also discuss factors that could make the outlook bust.  

Sea Surface Temperature (SST) anomalies…

 

The latest SST anomalies shown on the map from the NOAA Coral Reef Watch show something very spectacular. Looking at the map we can see that the vast amount of the global oceans is above average to well above average. When I look at the SST record, I couldn't find another year that had the Atlantic so warm during an El Nino. 

In fact the oceanic water near Peru and Ecuador in Nino Region 1+2 are well above Average, and likely record breaking. We also have that warm blob in the western North Pacific.

 We do have some cooler SST in the far Southern Hemisphere. The only other real exception, is that large patch of cool SST off the West Coast up into the Gulf of Alaska. But for the most part the global oceans are above average.   

 Those very warm SST off the West Coast of South America will continue to push west into the Central Equatorial Pacific.

The Atlantic continues to see those above average SST anomalies.  SSTs off the West Coast of Africa out into the MDR across the Central Atlantic are above average. We also have those well above average SST in the Gulf of Mexico (GOM) and off the East Coast.

 The Developing El Nino…

El Nino is looking increasingly likely. This means that the ENSO is in the positive phase. As I said in Part Two, the SOI has switched to negative values. But Nino region 3.4 is still reading in the neutral range. With the Eastern and Central Pacific warming and SOI values decreasing; it can be a strong indication of El Nino development.

The latest weekly Nino region 3.4 index value was +0.4°C, with the easternmost Nino 3 and Nino 1+2 regions at +0.8°C and +2.7°C, respectively.

Looking at the Subsurface water temperatures; we can see they are above average from the International Dateline eastward to the Coast of South America. All of this warm subsurface water is the result of the triple dip La Nina. All that is needed is strong westerly winds to cause upwelling and bring all that warm water to the surface. How much upwelling occurs will be a major player in how strong this El Nino becomes.

Right now, the El Nino looks to start out weak, then it should go into a moderate to strong phase.

This would mean we would see more vertical wind shear during the 2nd half of the Season.

There will be a bit of a lag as the atmosphere resets from ENSO neutral/weak El Nino to moderate too strong. So, the first half of the season could act more La Nina like. 

A few of the models like the Australian are calling for a very strong (super) El Nino.

 Typically during El Nino the Caribbean sees less activity. This is due to increased windshear over that part of the Atlantic Basin. 

The Pacific Decadal Oscillation (PDO)…

Right now, the current index is -3.05 which makes the PDO strongly in the negative phase. As I said in the Summer Outlook, The PDO has a big influence on the ENSO. If the PDO is in the same phase as the ENSO their Associated impact can be amplified. However, if they’re not in the same phase the associated impact can be reduced.

There are signs that the negative PDO has reached its peek and is starting to collapse. If the PDO does become positive, that wouldn't happen until late Summer or more likely during the Fall into Winter.   

So, while El Nino is a typical signal for a quieter tropical season in the Atlantic Basin.  With the PDO in a negative phase, this could allow for a slightly higher number of tropical cyclones in the Atlantic this season, than would be typical for a El Nino season.  

 The Atlantic Multi-Decadal Oscillation (AMO)…

As I’ve already covered, the Atlantic Basin is very warm

The AMO is a cyclical variation of sea surface temperature anomalies over the North Atlantic Ocean that influences weather conditions across the globe, especially North America, Europe and Northern Africa. It typically has a cycle of 50 to 70 years.

 

The positive phase is characterized by warm SSTs over much of the North Atlantic

 

The negative phase is a mirror image with cool surface waters over the North

 

When SSTs are anomalously high (positive phase), hurricane activity in the North Atlantic is increased.

The African Monsoon looks to be very active this season, leading to more tropical waves coming off the West Coast of Africa.   .

Analogues…

These are the years I've decided to use for 2023. The years are the best general match to all the factors going on leading into the 2023 Atlantic hurricane season.

1957, 1965, 1972, 1976, 1982, 1997, 2002, 2009, 2015, 2019

1957

1965

1972

1976

1982

1997

2002

2009

2015

2019

1967 thru 2019

2023

1957 and 1976 are being used because both were El Ninos that came after triple dip La Nina’s.

1972 is the closest match to current global SSTs. 1997 is the second closest match, with 1982 just behind that.

 Based on what I'm seeing there is a good chance this El Nino could be very strong.

The Numbers…

In part two I said this will be a slightly below average to average season, with 10 to 14 named storms 4-7 hurricanes and 1 -2 major hurricanes.  The seasonal ACE looks to be 60-90.

But with the other factors I’ve mentioned in part three. The seasonal activity could end up  above average.

My final numbers are 14-20 named storms, 8-12 hurricanes, 3-5 major hurricanes. The CONUS could see 2-4 landfalls with one of them possibility being major. The ACE would be 100-150.

 Hot Spots and impacts…

A moderate risk for a few Cape Verde systems.

 So, we should see recurving systems out in the Atlantic that head into the North Atlantic.

 But the greatest risk for tropical cyclone development will be in the Gulf of Mexico and off the Southeast Coast. 

The risk of close in tropical cyclone development increases the risk for landfalling tropical Storms and hurricanes along the Gulf Coast and East Coast.

The East Coast is most at risk for Landfalling systems. There is a chance the Middle Atlantic and New England could be impacted.

Florida could very well be in the crosshairs once again this season.

With those very warm water temperatures, there is going to be the risk for rapid intensification.

What Could Go Wrong…

Even though El Nino looks likely, right now the odds are around 60%.  But as we saw in 2014 when a strong El Nino was being forecasted on the models. However unusually strong easterly winds in the summer of 2014 ended up  preventing the warm surface water from shifting eastward as seen in a typical El Nino events and left a reservoir of warm water below the ocean’s surface, resulted in the El Nino failing to really develop. But strong westerly winds along with the very warm pool of water that developed during the winter shifted east, this continued into the Spring and Summer of 2015 and led to the development of the Super El Nino of 2015-2016.  It is possible a similar change in the wind regime or some other unforeseen factor could end up stopping El Nino from developing this year.

The PDO is in an opposite phase from El Nino; this could lead to more of an active Atlantic hurricane season.

The above average SSTs in the Atlantic Basin, could very well help counter the El Nino impacts, at least somewhat.

Other possibilities that could happen with the ENSO

 A)    El Nino Modoki

There is a chance that the central equatorial Pacific namely Nino region 3.4 could warm faster than Nino 1+2, if that warm subsurface water makes it to the surface. I think the chance of this is low, but it can’t be completely ruled out.  There is research that supports the idea that El Nino Modoki’s lead to more hurricanes than usual in the Atlantic Ocean.

 B)    La Nina Modoki

The water temperatures are very warm in Nino region 1+2 off the West Coast of South America. But a closer look at the SST anomalies, show water temperatures are also rising near Indonesia off the province of Papua. This would mean that the SSTs in the central equatorial Pacific are slightly cooler.  That could technically be called a La Nina Modoki. Again this is a lower chance, but I can't discount it.  If this develops, we would be in another La Nina. Which would have a drastic influence on the Atlantic windshear profile. Coupled with those very warm SSTs. It could lead to a very active tropical season in the Atlantic.  

The most recent El Nino Modoki happened in 2019.

 Bermuda High…

We look to see the Bermuda high setup near the Azores and then drift west during the season. As the BH sets up in the western Atlantic in the 2nd half of the season. Helping to direct tropical waves/cyclones toward the US, possibly increasing the landfall risk. But increased windshear that looks to develop during the 2nd half of the season, could help counter at least some of the landfalling threat.

Final Thoughts…

There is no way of knowing the exact number of tropical cyclones are the exact track they will take. I’ve looked at past patterns and compared those to the current pattern. I’ve also looked at what I think the teleconnections are saying as to what could happen. I’ve also looked at return dates based on hurricane historic data. 2023 is going to be a difficult year for long range hurricane outlooks, due to the multitude of conflicting signals. I think the approach I’ve taken is reasonable after looking at all the data.

It is important to take the time to make a plan and also have a hurricane kit to keep your family safe.  

Well, that’s it

If you have any questions regarding this outlook, please feel free to send me a comment here or on my Facebook Weather Page here.

I have to add, The National Hurricane Center has determined that that the nor’easter back in January was actually a subtropical storm. This would make it the first Atlantic cyclone of the 2023 season.  It is being designated as “AL012023.” Since the January storm is considered the first of the season, the next tropical depression that forms will be designated as “tropical depression 2.” If it strengthens into a tropical storm, it will be named Arlene.