It’s mid-August, do you know where your hurricanes are?

Sea surface temperature anomalies showing the El Niño in the Pacific. Notice how much warmer the Pacific is than the Atlantic

Sea surface temperature anomalies showing the El Niño in the Pacific. Notice how much warmer the Pacific is than the Atlantic

Normally we would have had a hurricane by now in the Atlantic Basin. Normally.

This year is far from normal.

First of all, El Niño is in full swing along a vast stretch of the tropical Pacific. This abnormal warming of both the surface and subsurface waters has created all kinds of weather havoc with more to come. Luckily for those of us in the Atlantic, El Niño is typically a big bully to developing hurricanes.

Second up – wind shear and lots of it. Strong upper level winds blowing across the deep tropics, especially coming through the Caribbean, has done its job of keeping fledgling hurricanes from taking flight. This too is a common occurrence during El Niño years.

Saharan Air Layer still holding on in the tropical Atlantic

Saharan Air Layer still holding on in the tropical Atlantic

Third culprit – dry, sinking air. A lot is often made of African dust and the Saharan Air Layer but I think it sometimes gets more attention than it deserves. There have been quite a few impressive outbreaks of dry, warm air spewing off the Sahara in recent weeks and months but it is the overall pattern of dry, sinking air that has really put a lid, literally, on tropical development in the Atlantic. Any why not? With all of the warm water in the Pacific, the upward motion has been focused there while the Atlantic, though warmer than perhaps some had expected, is still out of balance and thus the non-rising nature to the atmosphere. This lack of general upward motion has been a serious impediment to development this season.

Now enter 96L in to the picture. What about its chances?

NHC 5-day Graphical Tropical Weather Outlook showing 96L and its potential development/track area

NHC 5-day Graphical Tropical Weather Outlook showing 96L and its potential development/track area

The National Hurricane Center is giving it a high chance of becoming a tropical depression sometime this week. After all, it’s mid-August, water temps are plenty warm and we have a well developed tropical wave and surface low moving across the deep tropics. It seems like it would be all systems go, right? Maybe but probably not – at least not this time.

Conditions for development are marginal right now though the water is warm, there’s no doubt about that. But warm water alone is not enough. The environmental conditions needed to produce deep, tropical convection just seems to be lacking once again in the tropical Atlantic. This was predicted very well in advance of the season by models such as the ECMWF seasonal forecast. In other words, it’s no surprise that we’re seeing such little activity. That being said, there is at least a chance that 96L makes it to become a tropical storm over the open Atlantic. If so, its name will be Danny.

Recent intensity plots for 96L

Recent intensity plots for 96L

Some of the intensity models indicate that 96L will become a tropical storm and eventually a hurricane. I just have a hard time seeing this considering the hostile environment ahead of the system. Never the less, we have something to watch now and as August comes to a close in a couple of weeks, we may have even more to watch. For now, the hurricanes have been shut out completely this season in the Atlantic and it looks to remain that way for the time being. We shall see.

Check out my video blog which will cover all of these topics and more – I’ll have it posted later this afternoon.

M. Sudduth 6:00 AM ET August 17

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Tropical Atlantic trying to produce activity in the face of overwhelming odds

Recent satellite photo of 94L off the west coast of Africa

Recent satellite photo of 94L off the west coast of Africa

The National Hurricane Center has recently identified an area of interest, a strong tropical wave with an associated low pressure center, not too far off the west coast of Africa. The tropical wave, labeled as 94L, is moving westward over warm water and actually has a slim chance at further development. However, the environment well ahead of this wave of low pressure is about as hostile as it gets. The combination of very strong upper level winds coupled with a generally stable atmosphere should clip the wings of this fledgling before it ever takes flight.

The global models are “seeing” this scenario as well and none are really doing much with 94L once it leaves the favorable environment that it is currently moving through.

It is interesting to note that after 94L seemingly dies off as it moves farther west that more strong tropical waves emerge from Africa in the coming days and also try to develop. I have to wonder – is the Atlantic just too hostile to allow any of them to flourish and become a tropical storm or hurricane? Or, is each one analogous to arrows being shot at a target: if you have enough, eventually one will hit. We are moving in to August very soon but it’s early August and even during a year without a strong El Nino, climatology tells us that eastern Atlantic development is rare until later in the month.

94L will be interesting to watch and will likely generate a lot of discussion within the hurricane blogosphere but from what I am seeing, that will be the extent of it. We never completely dismiss an area of interest and as such, I’ll be monitoring the future progress of this feature, even if it means watching from afar as it heads straight in to the sheer machine waiting to its west.

I’ll have more here tomorrow morning.

M. Sudduth 3:15 pm ET July 29

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El Niño not likely to be a factor for 2015 Atlantic hurricane season

Even though it is January, there are clues that we can look for when trying to figure out how busy the upcoming Atlantic hurricane season may be. One of those clues is the state of the El Niño.

As we know, El Niño or the abnormal warming of the tropical Pacific, tends to suppress Atlantic hurricane activity due to a number of factors. For a good deal of 2014, it looked as though a rather substantial El Niño event was going to unfold – it failed to do so. However, the tropical Pacific did warm quite a bit and in fact, most of the warmest water on the globe was found in the Pacific during last year’s hurricane season. This is a big reason why the east Pacific was so very busy and the Atlantic was not.

As of early January, the tropical Pacific was only slightly warmer than usual with a noticeable decline in sea surface temperatures in the east Pacific, just west of Central America. In fact, as far as I can tell, we are not even in an official El Niño right now as the thresholds have not been met. This is not surprising if we look at some other aspects of a traditional El Niño event.

One of those aspects is the SOI or Southern Oscillation Index. Typically the more negative it is, the more likely we are to see El Niño conditions prevail in the atmosphere AND in the oceans. What’s the trend over the past 90 days been? A slow and steady rise in the SOI. As the chart shows, October was -8.2, November was -8.0 and December was -7.6 with the current daily value showing +4.4. What does this mean? In short, it means that the pressure pattern is such that the trade winds are not all that weak across the tropical Pacific and thus the El Niño is being held back if not stopped completely.

Latest SOI chart from the Australian BOM

Latest SOI chart from the Australian BOM (click to view full size)

More evidence of the collapse of the El Niño can be seen via the temperature depth anomaly chart from the Climate Prediction Center. This shows us what the temperature profile is of the tropical Pacific from the surface down several hundred meters. Clearly you can see the loss of the warm pool as the animation progresses over the past several weeks. In fact, cooler anomalies are showing up in the eastern Pacific at a depth of around 110-150 meters. Unless more warm water begins to migrate eastward (from left to right on the chart) then the warming of the tropical Pacific will be very slow if not stopped entirely.

Equatorial Pacific Temperature Depth Anomaly Animation

Equatorial Pacific Temperature Depth Anomaly Animation (click to view full size)

So what does this all mean as far as impact on the 2015 hurricane season? While it’s too early to be confident about the demise of the El Niño, the most recent forecasts indicate that the odds of neutral conditions are beginning to outweigh El Niño as we get in to the Atlantic hurricane season which begins in June. This is very important because a cooler tropical Pacific would likely mean less upward motion in that region compared to what we saw in 2014 and this could lead to a better chance for Atlantic development, even if only a little. Remember, 2014 was not too far off from being an average season and so any increase in activity this year would seem to most people as being quite busy, especially considering how slack things have appeared to be since 2012.

Early January 2015 forecast for ENSO state - notice how the green (neutral) outweighs the red (El Nino) beginning as soon as the Feb/Mar/April time frame

Early January 2015 forecast for ENSO state – notice how the green (neutral) outweighs the red (El Nino) beginning as soon as the Feb/Mar/April time frame (click for full size image)

There are many other factors to consider as we enter the 2015 Atlantic hurricane season but the state of the ENSO is a big one and thus far, it appears that it will not be much of a negative influence. Obviously, the climate models can and do make gross miscalculations and we could end up with a raging warm episode by late summer. However, with other signals leaning in the direction of a non-El Nino event shaping up, I tend to think that the forecast will be pretty accurate and that we will not have an El Nino during the 2015 hurricane season. We shall see…

I will post an update to this information in early April, right before the National Tropical Weather Conference which is being held in South Padre Island again this year. By then, we’ll be within 90 days of the hurricane season getting started. I’ll have other topics posted before April of course but that’s the next logical time to take a look at the ENSO state again. Until next time, stay warm!

M. Sudduth 9:26 AM ET Jan 14

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How’s that El Niño coming along?

Remember back in the spring when it looked like we might have a super-jacked-up El Niño? Well, that didn’t work out as some had thought, or hoped, but it does finally look as though El Niño is upon us.

Warm tropical Pacific, as seen by the orange and red plume spreading west from South America, indicates El Nino is all but here.

Warm tropical Pacific, as seen by the orange and red plume spreading west from South America, indicates El Nino is all but here.

First of all, what exactly is an El Niño? In short, it is an abnormal warming of the tropical Pacific, roughly near the Equator. As trade winds weaken, or sometimes even reverse, warmer water is able to establish itself in a band stretching from South America westward for more than two thousand miles in to the tropical Pacific. The result is often a tumultuous set of weather patterns that are thrown in to disarray due to the warmer than normal area of water.

For the Atlantic Basin hurricane season, El Niño usually equates to fewer and less intense hurricanes. It looks as though the growing warm event did not have much impact on the 2014 season directly although some of the atmospheric conditions that were present can be linked to El Niño-like patterns. An example would be the abnormally high upper level wind shear across the Caribbean and most of the tropical Atlantic this season. That is typical of El Niño despite the fact that we were not technically experiencing El Niño conditions for most of the season. In any case, it looks as though the real deal is coming on now and will be with us for the next several months at least.

Current ENSO forecast from CPC/IRI - 11/20/14

Current ENSO forecast from CPC/IRI – 11/20/14

According to the latest updates coming out of various meteorological agencies around the world, we are very close to officially having an El Niño event take place. Typically sea surface temperatures across a certain region of the Pacific need to exceed .50 degrees Celsius above the norm for an El Niño to be declared. This also needs to span a specific amount of time, not just a few days or weeks. The latest calculation from the Climate Prediction Center indicates a sea surface temperature anomaly of .80 degrees Celsius, .30 above the minimal threshold. It won’t be long now and the 2014/15 El Niño will be official.

Aside from the usual fun and games that come with El Niño for winter and spring in the Northern Hemisphere, I like to look and see what the outlook is for the coming hurricane season. It is not typical for an El Niño to last for more than a year, it usually peaks in the early spring once the onset is official and slowly fades out during the summer and fall.

So far, it looks like we will see El Niño conditions prevail through at least the next three to six months. Computer model forecasts for El Niño are notoriously bad for long lead times. After all, many were calling for anomalies exceeding 2.0 degrees Celsius by now which would be an exceptionally strong event. Obviously we are nowhere near that mark and the models that were predicting such drastic increases in ocean temperatures were flat out wrong.

One aspect of this El Niño event that I am watching closely is how well it performs at seeding the tropics with more moisture. I believe that the cooler than average Pacific over the past several years, until this year really, has helped to dry out the tropics somewhat. This might explain to some degree why the Atlantic Basin has been fairly inactive hurricane-wise after the busy 2012 season. Now that El Niño is coming on, more moisture will be fed in to the tropical atmosphere over thousands of miles which should, in turn, spread around the globe, increasing moisture and thus vertical instability in the tropics. We saw this already with the very busy east Pacific hurricane season. It is my theory that El Niño may help to jump-start tropical cyclone activity world-wide starting in 2015. This may be especially true if in fact the warm event fades as it should do starting in the spring and early summer. We will be left with added moisture in the deep tropics combined with gradually cooling tropical Pacific waters. The result, in my opinion, should be an increase in Atlantic hurricanes beginning in 2015, probably spanning a few years after. We shall see. Even if 2015’s hurricane season is more busy than the past two, it won’t necessarily mean that I was correct. I just think that the simple fact that cool water does not lead to as much evaporation and thus moisture in the atmosphere helps to explain, even if only a little, why the global numbers of tropical cyclones have been down in recent years.

For now, El Niño seems almost a certainty. How strong the event is and how long it lasts will certainly shape not only the winter and spring weather patterns but also next year’s Atlantic hurricane season. It is just one piece of the puzzle and it’s a fairly large one at that.

For more in-depth information on the latest thinking from the International Research Institute, check out this link: IRI Technical ENSO Update Published: November 20, 2014

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Tropical wave in cental Atlantic a sign of what’s ahead

Tropical Weather Outlook map from the NHC showing area of interest in the central Atlantic

Tropical Weather Outlook map from the NHC showing area of interest in the central Atlantic

Not much going on in the tropics since Arthur earlier this month. This is typical for July which is usually a very quiet month in the Atlantic Basin.

In fact, we did not have any tropical waves to flare up worth mentioning until yesterday when the NHC issued an outlook for one in the central Atlantic. It rolled off of Africa a few days ago and has a low pressure area associated with it at the surface. Water temps are warm and overall, environmental conditions are generally favorable for development right now. However, this is likely only temporary as it looks as though conditions will not be so great for development as the week wears on. It’s just too early in the season yet for robust Cape Verde tropical waves to get going this far east. We’re still looking at another month or so before that happens.

The presence of this system does remind us of what could lie ahead. As I mentioned, July is usually not very active, especially in the deep tropics. Once we get in to mid to late August, conditions change and we begin to see more and more active tropical waves moving west from Africa. At that point, it will come down to upper level winds and, perhaps more importantly, instability in the atmosphere. If the mid-levels of the atmosphere are too dry with lower humidity value than usual, then the tropical waves will struggle to develop deep convection and will remain weak. On the other hand, if moisture levels are where they should be or are above average, then we would likely see a very busy August and September.

I believe that much will depend on the situation with the El Nino which was forecast to be coming on quite strong by August. As it turns out, there is barely any El Nino to talk about, especially in the central regions of the tropical Pacific. It just never made it and what warming there was has all but vanished. However, the water just west of South America, extending westward for several hundred miles, is still quite warm compared to normal. This could have just enough negative influence on the Atlantic side to help keep the peak months of August-October quieter than normal.

One thing I will be watching for is how much, if any, cooling takes place in this region of the Pacific. There are indications that we could see a considerable drop off in the surface temperatures of this area and if this happens, I suppose it could remove at least a portion of the negative influence for the Atlantic Basin. It’s just so complicated and hard to tell if one puzzle piece really makes that big of a difference considering how the other pieces fit together and interact with each other.

For me, the tropical wave that the NHC is talking about this morning is a sign that we are approaching the peak months of August-October. Thus it is a good time to remind you to be aware and prepared. Arthur was an interesting event in that it was so early in the season and it did not fall apart at landfall – instead, it continued to strengthen despite its close proximity to the North Carolina coast. If that is the way things will go this season, it won’t matter much if tropical waves develop far out in the Atlantic. What matters are the ones that would do so close to land, leaving little time to react. We’ll see how things shape up over the coming weeks but August is just around the corner and from there on, at least from a climatological perspective, the season should become more active. Time will tell just how active, that is the only certainty at this point.

I’ll have another blog post here tomorrow morning.

M. Sudduth 10:24 AM ET July 21

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