El Niño or El Nada?

Well, well, well. Look at what we have here. Yet another substantial El Niño forecast, by some, that is not likely to come to pass. There was talk earlier in the year that an ENSO (El Niño Southern Oscillation) event that could rival the 1997 “Super El Niño” was in the making. Finally, we had a new buzzword to supplant “Polar Vortex” and my how people ran with it. The prospects of a record-breaking El Niño seemed destined for the history books. I have to admit, the evidence seemed to support the possibility but then something happened, something quite simple: It didn’t happen.

Actually, it is much more complicated than that but that’s the bottom line, right? There is no super-sized El Niño in the making. In fact, we may barely make it to El Niño status before the year is out. But forecasters seemed so sure. What happened? For what ever reason, the atmosphere and the ocean failed to get married. They had a nice engagement but it was not meant to be. So we see parts of the Equatorial Pacific beginning to cool and the subsurface, that’s where the real story is. Let’s take a look.

Subsurface anomalies dated April 23, 2014

Subsurface anomalies dated April 23, 2014

Here is a subsurface analysis from April 23 that showed a large pool of very warm water compared to average. This warm pool was headed east and set off many people thinking that THIS was IT! Super El Niño was coming! You have to admit, that is one large area of positive anomalies but look west (the left side of the graphic). Even by April 23 it was obvious (to me anyway) that there were no reinforcements! I thought surely this warm pool would be followed by another one, maybe even stronger. Nope. None came.

Subsurface anomalies dated June 22

Subsurface anomalies dated June 22

In fact, as you can see in the second graphic, which is the most recent analysis, not only did the warm pool not get a reinforcing shot, the existing one shrank! And, wait a minute, what’s this? COLD WATER? Yep, that is a large pool of cold anomalies that has crept in to the picture. Hard to believe that just a few months ago, we were looking at the prospects of a globally challenging ocean/weather phenomenon the likes of which we haven’t seen since 1997! Unless something completely unexpected happens over the next few months, I think it is safe to say that a minimal El Niño event is in store if we even get to that point. Those cold anomalies are really interesting since they were not forecast to be there right now.

So what does this all mean? It means that computer guidance still has a long way to go when dealing with ocean/atmosphere coupling. El Niño doesn’t just happen – a complex series of mechanisms needs to be set in to motion and remain in motion for a period of time. If one side gives up, the whole system crashes. Perhaps it wasn’t meant to be or perhaps I am wrong and a Super El Niño will put me in my place before the end of the year. It had better get going soon, we’re almost to July and after that, the peak months of the Atlantic hurricane season arrive. With no substantial El Niño in place, I have to wonder….are the forecasts for a slack hurricane season also going to bust? After all, go back and read them, most make mention of El Niño and its negative influence on Atlantic tropical cyclone activity. No El Niño, no negative influence. Naw, that’s too simple, it can’t possibly be right.

I guess we’ll see. Let’s re-visit this on November 30, shall we?

In the meantime, we will watch the Southeast coastal areas for possible development over the next few days. Some of the global computer models are trying to cook up a low pressure area over the warmer-than-normal water that is lurking in the southwest Atlantic. I’ll have more on this over the weekend.

M. Sudduth 8:30 AM ET June 27

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Polar Vortex out, El Niño in?

Cross section of subsurface water in the tropical Pacific over the past few months. Clearly, a warm pool of water has developed deep beneath the Pacific and is expanding east.

Cross section of subsurface water in the tropical Pacific over the past few months. Clearly, a warm pool of water has developed deep beneath the Pacific and is expanding east.

The much maligned term “Polar Vortex” that was used quite often this winter within the weather blogosphere is about to be replaced….maybe. By what? El Niño. Yep. The Great El Niño could be making a comeback. Remember the Saturday Night Live sketch with Chris Farley about this phenomenon? It was a classic and just another example of how weather mixing with pop culture can be fun but sometimes quite wrong.

El Niño is not a single event like a storm or a hurricane. Instead, it is just a name that us humans have assigned to a change in the tropical Pacific that results in sea surface temperatures being warmer than the long-term average. Once a certain threshold has been met, we call it El Niño. Make no mistake, it will get a lot of play in the media, especially where Global Warming is concerned. The reason? The oceans act like giant cooling or heating agents. When the Pacific, the largest water basin on the planet, is warmer than it should be, then we typically see global temperatures spike – as if someone turned up the thermostat for the earth. My bet is that the pro-global warming crowd will be salivating at the potential El Niño event as it will help to boost their notion that man is screwing things up in a big way. I have no dog in that fight as it does not matter to me. What I mean is, so what? If man is making Earth warmer, who is going to go first to completely stop living in modern times? Anyone? That’s what I thought. My take is: adapt and mitigate. If not, we perish. No debate there, just ask the dinosaurs.

Back to the topic at hand.

The reason El Niño is important, other than acting like a massive thermostat for the planet, is that it seems to wreak havoc on the Atlantic hurricane season. The simple reason seems to point to higher than normal wind shear and sinking air across the tropical Atlantic due to the presence of the warmer than normal water in the tropical Pacific. In other words, El Niño would be perceived as a positive for those who would rather not deal with hurricanes; except for times when something like Andrew comes along. You can add to that list: Audrey, Camille, Alicia and even all of the landfalls of 2004. Those were all El Niño years. The point is, generally speaking, El Niño has a negative impact on Atlantic hurricane activity but this is not a guarantee. Kind of like how the 2013 hurricane season turned out. You just never know even in the face of what seems like a near certainty.

The reason behind the talk of an impending El Niño is due to several things that we can see going on across the tropical Pacific right now and within the past few weeks.

Pressure differences in the west Pacific have resulted in stronger winds blowing from the west. This causes a change in the way the ocean behaves and helps to generate what is called an oceanic Kelvin wave. I call it a Monkey Wrench in the ocean state. Normally, the trade winds in the Northern Hemisphere blow from east to west and thus the west Pacific is almost always warmer than the east Pacific. When the pressure pattern is altered, for reasons yet unknown, then the wind reverses course and that warm water is pushed eastward. This happens more so at the subsurface believe it or not in what is called downwelling. Warm water is literally pushed downward and then begins a very slow trek eastward where it upwells in to the eastern Pacific. The result: the birth of El Niño. It’s much more complicated but that’s the general idea. No one knows precisely what triggers these events to begin the chain reaction but it appears, at least for now, that forces are being set in to motion that could have huge global impacts as we move through 2014.

As for predictions, computer models are very unreliable for predicting long term weather patterns. They just cannot resolve the complex atmosphere coupled with the ocean several months in advance. In fact, the ECMWF, considered to be the very best global model in the world, called for an El Niño event last summer. It did not happen. So we shall see. While there is mounting evidence to support an El Niño event taking shape this year, it’s not clear at all how strong the El Niño would be. Obviously, the warmer the anomalies (departures from normal or average) then the more dramatic the impacts would likely be. We just don’t know yet.

As for how this potential El Niño will affect the 2014 Atlantic hurricane season – well, let’s just make sure we remember Andrew in 1992 as a case study in “it only takes one”. Sure, the overall numbers may be way down compared to the past 15 years or so. All it takes is for one, and it doesn’t even have to be a hurricane, to spoil the summer fun.

Stay tuned. El Niño is about to show Polar Vortex the door…maybe. I’ll have an update on this in mid-April.

M. Sudduth 9:15 AM ET FEb 25

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Latest forecast suggests no El Nino in sight

Latest CPC/IRI ENSO forecast chart

Latest CPC/IRI ENSO forecast chart

It’s approaching mid-June and the latest info from the Climate Prediction Center and International Research Institute (CPC/IRI) suggests that El Nino is not going to happen this hurricane season.

First, what is El Nino and why is it an issue? Well, basically, it is the abnormal warming of the tropical Pacific along and near the Equator. This warming tends to throw off the typical weather pattens and usually equates to a below-average Atlantic hurricane season. This is due to stronger upper level winds, or shear, that streaks across the tropical Atlantic and Caribbean, cutting off the tops of developing hurricanes. In the absence of El Nino, we often experience a busy Atlantic hurricane season, especially if the tropical Atlantic sea surface temps are themselves running above average – as is the case this season.

For reasons not well understood, El Nino comes and goes every few years. In between we have neutral periods where the water temps are more or less average. Then we have La Nina or an abnormal cooling of the tropical Pacific. That phenomenon also has its own set of interesting side-effects which are better explained another time. For this season, we are looking at a neutral pattern setting up and remaining in place.

The latest data and forecast from the CPC/IRI suggests less than a 10% chance of seeing El Nino develop during the August/September/October peak time of the Atlantic hurricane season. This should act to allow for prolofic development once we reach mid-August and beyond, especially considering the warmer than average SSTs in the Atlantic.

This chart gets updated a couple of times per month and I’ll post another write up on the state of the ENSO or El Nino Southern Oscillation towards the end of the month. In the meantime, the tropics are nice and quiet with no areas of concern noted in either the east Pacific or the the Atlantic.

M. Sudduth

 

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Where is the El Niño?

August SST anomalies in the tropical Pacific

August SST anomalies in the tropical Pacific

Earlier in the year, it seemed almost a certainty that El Niño would develop in the tropical Pacific. As we moved through the spring and summer, the tropical Pacific began to warm and it looked like we were well on our way to seeing an El Niño develop. Then, it just stopped.

In recent weeks, the tropical Pacific has actually cooled significantly, especially in the

October SST anomalies in the tropical Pacific. Notice the cooling along the Equator

October SST anomalies in the tropical Pacific. Notice the cooling along the Equator

central Pacific. Just compare the two SST anomaly maps from August and now. You can clearly see a substantial decrease in SST anomalies across the tropical Pacific.

So what happened? It’s hard to say. The latest report from Australia’s Bureau of Meteorology site addresses the retreat in SST values across the region that was warming up until recent weeks. It seems that the pressure pattern across the Pacific changed and the abnormally weak trade winds picked up, cooling the sea surface rather quickly.

Sub-surface temperatures in the tropical Pacific. Notice the distinct cooling in recent weeks

Sub-surface temperatures in the tropical Pacific. Notice the distinct cooling in recent weeks

It is also very interesting to note that the sub-surface temperatures also have declined in dramatic fashion since the late summer. While there was a growing pool of warm water since the spring, it suddenly cooled and now we have a noticeable large area of cooler than normal sub-surface water across a large section of the Pacific. This means that the chances of seeing a true El Niño are getting quite slim.

Why is El Niño even an issue? Well, aside from the weather patterns that El Niño tends to have an influence on globally, if we look at the Atlantic hurricane season specifically, there tends to be a suppression of overall activity. This is mainly due to the increase in tropical convection over the Pacific which is due to the increase in sea surface temperatures because of the El Niño. Persistent tropical convection over the Pacific will usually mean stronger upper level winds and sinking air across the tropical Atlantic. These two negative factors limit the amount of development typically seen in the Atlantic main development region. It’s interesting that the end result seems to have been present this season. In other words, we have seen a limit to the numbers of hurricanes that have developed in the deep tropics. In fact, the ONLY major hurricane to form did so well outside of the typical breeding grounds and was very short-lived.

I do not understand why we had the effects of El Niño without the El Niño itself. Perhaps the atmosphere was responding as if there was an El Niño coming on even though the tropical Pacific was not quite there yet. Who knows? It’s all so complex and there are many interactions between the ocean and atmosphere that it’s difficult at best to know the real reasons behind some of this.

The bottom line is that El Niño has been put on hold, or so it would seem. It may be that it never fully takes root and this could have an effect on the upcoming winter season and most certainly the 2013 Atlantic hurricane season. None of the reliable climate models indicate an El Niño for the early part of 2013 and one could reasonably assume that there won’t be an El Niño during the peak of next year’s season in August-September-October. And yet, even with the near-El Niño observed this season, the Atlantic still has managed to produce eight hurricanes total. This is above the 100 year average. And, on the topic of abnormal sea surface temps, the tropical Atlantic was thought to have been cooler than normal this season. It wasn’t and still isn’t. In fact, a good deal of the tropical Atlantic is running nearly 1 degree C above normal right now. I guess there is a lot we still do not understand about our oceans and the atmosphere.

I’ll have another post here later this afternoon to address the current goings on in the tropics and what we might expect with 98L.

 

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Favorable MJO pulse could lead to more development but not where we would expect

ECMWF indicating a more favorable MJO pulse coming for the Western Hemisphere

ECMWF indicating a more favorable MJO pulse coming for the Western Hemisphere

It’s October and climatology would suggest that we would be looking in the western Caribbean or Gulf of Mexico for the best chance of development right now. While this may be the favored region, the tropical Atlantic is not quite ready to shut down just yet and we may actually see something develop out that way over the next several days.

Right now, the MJO pulse for enhanced upward motion and tropical convection is still weak and centered over the west Pacific. However, it looks as though the MJO will strengthen and begin to shift eastward around the tropics, heading in to the Western Hemisphere soon.

Add to this an existing area of low pressure associated with a tropical wave over the deep tropical Atlantic and we may yet see another named storm before all is said and done. The arrival of the favorable MJO pattern could be the spark needed to get this disturbance, actually labeled as 98L, to spin up and be some thing to track.

Looking at the various global models, the GFS seems to be the most ambitious with development though it does not take place until about a week out. I am leery about putting too much faith in any model that indicates development that far out in time. However, considering the favorable conditions that look to be present, I would not rule out the possibility that we will in fact see 98L slowly come together over the next several days.

In addition, it looks like the steering pattern will more typical of summer than fall and as such, 98L may track fairly far to the west over time and not turn out to the open Atlantic like Nadine and Oscar did. I suggest that interests in the Lesser Antilles pay close attention to 98L over the next week. It is possible that some impacts will be felt in the islands but to what extent, it’s hard to say.

Elsewhere, 97L remains off the coast of the Southeast U.S. and is bringing showers and some thunderstorms to the Bahamas but that’s going to be the limit of the impact from this system. Upper level winds will preclude any significant additional development.

In the east Pacific, TS Olivia will track south of west in the coming days and fizzle over the cooler Pacific waters. In fact, the Pacific is quite a bit cooler than the major climate models were predicting for this time of year, a sign that the much talked about El Nino has not come to pass. This may have an impact on the remaining weeks of the Atlantic hurricane season since El Nino conditions typically thwart late season Atlantic/Caribbean development. There are no other areas of interest in the east Pacific to monitor right now.

For those who have our iPhone app, be sure to catch today’s Hurricane Outlook video which will be posted within the hour. I’ll go over in extensive detail all of the topics in the blog post plus take a look at the state of the ENSO and how much the Pacific has cooled in recent weeks. I’ll have more here tomorrow.

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