Consensus growing for active hurricane season

We are now less than three weeks away from the start of the 2016 Atlantic hurricane season and already it looks to be a busy one. Before we jump to the “sky is falling” conclusion, let’s look at things objectively and put it in to some perspective that most can understand.

Subsurface anomaly chart showing the growing area of cooler than normal water mounting in the tropical Pacific

Subsurface anomaly chart showing the growing area of cooler than normal water mounting in the tropical Pacific

What we know is that the great El Nino of 2015/16 is almost certainly dying out. We can see this by looking at various data from a variety of sources. One of those is the subsurface anomaly chart that I have included here. Clearly the warm surface water is being eroded away with a vast expanse of cooler than normal water lurking across most of the tropical Pacific. This will very likely herald the arrival of La Nina conditions or an abnormal cooling of the Pacific along the equatorial region. In short, this is typically seen as a favorable sign for the development of Atlantic hurricanes. The sooner we see La Nina set in, and the stronger it is, the more influence it will have on enhancing the chances for Atlantic hurricane development once the season gets going.

In addition, we also know, again by looking at actual data, not computer model projections, that the Atlantic Basin is warming in the area between Africa and the Lesser Antilles. This is also called the MDR or Main Development Region. The irony here is that there were some indications in previous weeks that this region would actually cool abnormally; so far, it has done the opposite.

Check out the very latest NOAA/NESDIS SST anomaly map for the region. Water temps are running above normal across the entire MDR and in to the Caribbean Sea. This is a stark difference from what we saw last season although the MDR did warm some as the season progressed. Right now, the region is warmer than we have seen it since the 2013 season and this, coupled with the loss of the El Nino, should give another check mark in the column of enhanced hurricane Activity for the Atlantic.

Latest NOAA/NESDIS SST anomaly map showing a very warm tropical Atlantic

Latest NOAA/NESDIS SST anomaly map showing a very warm tropical Atlantic

Warm water alone does not make hurricanes. The atmosphere needs to cooperate as well with aspects such as moisture level and wind shear being take in to account. Right now, those parameters don’t matter too much since it’s just May. However, conditions do seem to be a little less dry in the mid levels of the atmosphere in parts of the tropical Atlantic which is yet another indication that things may be busier than we’ve seen for quite some time. Shear will drop as the summer approaches and the westerlies retreat to the north. Once we get to August, the beginning of prime time for the season, it looks like all systems go for a busy time ahead.

With all of this mounting evidence for a busy season, it comes as no surprise that several respected agencies are forecasting either an average season or slightly above average. So many different entities are making forecasts now that it’s hard to keep up. The trend however is what is interesting to me. All of them see a busier Atlantic than the past few seasons and that will seem very busy considering how relatively quiet things have been since 2012. We will get a new forecast from Dr. Phil Klotzbach and his team at CSU in early June. NOAA will release their seasonal outlook soon as well. I think it is safe to say that, at least for now, the scale has tipped in favor of the Atlantic.

None of this matters as far as who would be impacted. I need to make that very clear. Knowing that the general large scale environment favors more hurricanes is helpful, I think anyone would agree with that. You’d rather know than not, right? Just don’t get caught up in the headlines and lose sight of the fact that even a 40 mph tropical storm can ruin your entire life – or even end it. It’s all about the impact (hence why our app is called Hurricane Impact) and no forecast can tell you with any degree of certainty what impact you will face this season.

The bottom line here is that you’re going to hear a lot about the “busy hurricane season” coming up. What you won’t hear as much about is how you can process that information and make use of it. My advice is to use that info to beef up your knowledge of hurricanes and what to do if one comes your way. A busy season does not necessarily equate to one with many (or any) landfalls. It does up the chances but no one really knows by how much. That part of the equation comes down to timing and placement of the would-be hurricane within the Basin.

It’s almost time. We are ready and hope to help you to be as well.

I’ll have more here on the 15th when the east Pacific hurricane season begins.

 

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El Niño on its way out – to be replaced by….?

The strong El Niño that we heard so much about over the past several months is beginning to weaken (has been for a few weeks) and will soon be just a faded memory.

Current data and computer model forecasts overwhelmingly favor the continued demise of the current El Niño which was one of the strongest on record. Once this happens, what will replace it? The answer to that question is not as clear but has possible huge implications on the upcoming hurricane season for the Atlantic.

First, a quick re-cap of what El Niño is.

Current look at SST anomalies across the tropical Pacific and the tropical Atlantic

Current look at SST anomalies across the tropical Pacific and the tropical Atlantic

The easiest way to understand the El Niño phenomenon is to think of an abnormal warming of the Pacific along the Equatorial region – usually extending from the coast of South America (where El Niño gets its namesake) westward in to the tropical Pacific. How far west and how much warming then determines the extent of the effects from said event. In the case of the current El Niño, some areas peaked out at roughly 3.0 degrees C above average – quite a significant deviation from normal.

Now things are changing. The warm episode is fading as much colder water in the subsurface continues to gather in the west Pacific, slowly moving eastward and closer to the surface. Once the trade winds return to normal across the region, this cold water will have a chance to over take the El Niño and finish it off for good. It’s just a matter of time.

Latest subsurface analysis showing the growing pool of cold water in the western Pacific

Latest subsurface analysis showing the growing pool of cold water in the western Pacific

As you can see by the computer model chart, the signal is very strong that El Niño will be gone by summer. How far gone and whether or not the Pacific does in fact swing the other way remains in question but most of the reliable long-term guidance at least suggests the possibility of La Niña conditions setting in by fall. Why does this matter? Hurricanes, that’s why.

We should all know by now that El Niño typically equals a quieter, less intense Atlantic hurricane season. This is due to strong wind shear generated across the deep tropics and other factors that act to kill off developing storms before they can get too strong. This doesn’t mean everyone is safe during an El Niño but the intense hurricanes on the Atlantic side are often kept at bay.

Latest IRI/CPC model output chart which clearly shows the demis of the current El Nino

Latest IRI/CPC model output chart which clearly shows the demise of the current El Nino

Conversely, La Niña presents us with the opposite effect. Shear is typically very low across the deep tropics and tropical seedlings have a much better chance of becoming strong hurricanes at some point. It should be pointed out that La Niña does not necessarily mean someone will get hit by a nasty hurricane. On the whole, La Niña tends to have more dreaded landfalls and so it tends to stick out more – especially compared to warm events or El Niño.

Looking at the average of the dynamic models, it would appear that El Niño is on its way out and could be replaced by La Niña conditions by late summer early fall – just in time for peak hurricane season in the Atlantic.

It wouldn’t be fair to not mention that there are other large-scale factors than can shape a hurricane season. The mere absence of El Niño can certainly change things and allow for more development but it is just one piece of the overall puzzle – a large piece, but not the only one.

Water temps off the coast of Africa have warmed considerably in recent weeks, something that will need to be monitored closely as we get in to the Atlantic hurricane season

Water temps off the coast of Africa have warmed considerably in recent weeks, something that will need to be monitored closely as we get in to the Atlantic hurricane season

Atlantic sea surface temperatures will also be a huge factor and right now, especially off the coast of Africa, those temps are running above the long term average. This can change, heck, it’s only February, but these are the puzzle pieces we keep an eye on in the off-season.

By mid-April, we will get a solid look at what to expect as Dr. Phil Klotzbach and his team from Colorado State University issue the first quantitative forecast for the Atlantic Basin. I can assure you that the state of the Pacific – whether it be El Niño or La Niña – will weigh heavily in to his predictions. Once we get to June, the outlook becomes more clear and again we’ll have an update from the team at CSU.

For now, it appears that the writing is on the wall. La Niña may be coming and if so, we just might have more to track than we have in quite some time.

I’ll have more on this topic in a few weeks as more data and other information becomes available.

M. Sudduth 12:55 pm ET February 11

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Rare January tropical activity in Pacific, possible subtropical storm for Atlantic

You have no doubt heard plenty about the record-setting El Niño in the Pacific. It has been blamed for a litany of foul weather across the globe; whether all of those events are directly related to the El Niño remains to be seen.

Now we can add a rare January tropical storm to the list of El Niño-induced weather anomalies. The Central Pacific Hurricane Center (CPHC) is tracking tropical storm Pali, well to the southwest of Hawaii, not far from the Equator actually.

Check out the tracking map and you’ll see that the storm is located unusually far to the south and this is likely one of the reasons why the storm formed in the first place. Add the very warm El Niño water and a perfectly-timed westerly wind burst from the tropics and the result is a January tropical storm.

Tropical storm Pali tracking map from the CPHC

Tropical storm Pali tracking map from the CPHC

No worries about Pali – it is forecast to basically meander slowly well away from significant land masses and poses no threat to Hawaii. Still, it is yet another in a series of interesting, if not record setting, events that the current El Nino is at least indirectly associated with.

Meanwhile, the Atlantic, or more accurately, the subtropical Atlantic, has its own storm system worth watching.

Ocean storm in the vicinity of Bermuda that has a chance to become a subtropical storm over the next few days

Ocean storm in the vicinity of Bermuda that has a chance to become a subtropical storm over the next few days

The National Hurricane Center issued a special outlook product yesterday highlighting a strong ocean storm between the Bahamas and Bermuda. While currently non-tropical in nature, meaning that the storm has more or less the characteristics of a Nor’easter over warm water, there is a chance that environmental conditions, part of which also include warmer than usual water temps, could lead to the storm becoming more subtropical in the coming days. This basically means that the storm separates itself from any frontal boundaries in the vicinity and becomes more focused with deeper convection or thunderstorms closer to the center. This is typical of ocean storms that form out of the tropics or what we call the subtropics. Thus, it’s deemed a subtropical storm, kind of a first cousin to a classic warm-core tropical storm that we are more used to tracking during summer and fall.

Right now, the type of storm matters little for interests in Bermuda. The weather has been stormy for the past day or so with periods of heavy rain and gusty winds. The fresh water collected on the string of small islands is always appreciated but this unusual weather pattern is making for an unpleasant few days for the region.

Computer models indicate that the storm system will move generally east-southeast and make its way in to the open subtropical Atlantic. Water temperatures are not warm enough for a pure tropical storm to develop but it is possible that enough energy can be drawn from the Atlantic to allow the storm to acquire what I described before: more subtropical characteristics. If so, it would be named and would be Alex, subtropical storm Alex that is.

Once past Bermuda the storm poses no threat to land and is likely to be on the weather map for quite a few days since steering currents look to leave it hanging around out over the Atlantic in to next week.

So there you have it. The year is starting off with some interesting things to talk about even in the face of an obvious lack of cold and snow for most of the East. Will this change anytime soon? Probably. For now, the most interesting weather seems to be over the oceans with little sign of any big winter storms looming for the Lower 48. However, it’s still early January, as with hurricane season, we know how quickly things can change.

I’ll post more on the Pacific and Atlantic systems over the weekend.

M. Sudduth 8:40 AM January 8

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Signs of change for 2016?

After a couple of false starts in recent years, a strong El Niño finally developed and is now firmly entrenched across a good portion of the equatorial tropical Pacific.

El Nino at its peak in the tropical Pacific

El Nino at its peak in the tropical Pacific

This El Niño event has led to a substantial increase in Northern Hemisphere tropical cyclone activity, mainly in the Pacific (obviously), increased storms for parts of western North America with more to come in the weeks ahead and a fairly wet pattern overall for much of the South and Southeast U.S.

The outlook from the various groups who monitor El Niño calls for a gradual weakening of this warm event  as we move in to 2016. In fact, there is some evidence in the long range climate models that perhaps a cooling phase of what is called ENSO (El Niño Southern Ocscillation) is in store by 2017, if not sooner.

Once past the winter and the influence of the current El Niño, things begin to look very interesting for next hurricane season for the Atlantic.

One glaring consequence of this year’s El Niño was the record level of wind shear across much of the Caribbean Sea. Strong upward motion in the tropical Pacific resulted in strong wind between about 5,000 feet and 40,000 feet across the western Caribbean and extending as far east as the Lesser Antilles at times. This is what caused would-be hurricanes such as Erika to weaken and ultimately dissipate. Only a narrow band of favorable conditions existed in the deep tropics where we saw hurricanes Danny and Fred form, far away from land areas.

Outside of the extreme upper level winds, in the southwest Atlantic, there was another area of favorable conditions and the resulting hurricanes Joaquin and Kate owe their existence to that fact. Otherwise, El Niño really did help kill off the Atlantic season as far as direct impact on the United States was concerned.

2016 might not have that protection and in fact, there is a good chance of that happening, according to the latest projections from a suite of computer models.

CPC/IRI Consensus Probabilistic ENSO Forecast

CPC/IRI Consensus Probabilistic ENSO Forecast

As of the December 10th update from the CPC/IRI (Climate Prediction Center/International Research Institute), the probability of El Niño conditions holding on through March 2016 are near 100%. After that time, things change quickly.

Once we get to spring, El Niño begins to fade as cooler water moves in from the subsurface and stronger trade winds resume across the tropical Pacific. This is reflected in the projections with the probability of El Niño conditions dropping to 60% by late spring.

Moving further out in time, the various models suggest only a 20% probability of El Niño holding on by mid to late summer 2016. This has huge implications on the Atlantic hurricane season since the absence of El Niño by itself is typically a positive signal for Atlantic tropical cyclone activity.

As we know all too well, there are many other factors at play and the Atlantic Basin seems to have the most year to year variability and is subject to large errors in forecasts for seasonal activity – 2013 being a prime example. There was no El Niño that year and it appeared that conditions would be favorable for one of the busiest seasons since 2005. Other unforeseen factors set in by summer and the season was one of the most tranquil in recent memory.

SST anomaly forecast going out to July 2016. Notice the blue showing up in the tropical Pacific - that is the beginning of La Nina conditions there

SST anomaly forecast going out to July 2016. Notice the blue showing up in the tropical Pacific – that is the beginning of La Nina conditions there

While the El Niño fades, another interesting phenomenon may begin to take shape. Some of the climate models are developing a very warm tropical Atlantic next year. If this comes to pass, especially if the far northern Atlantic is cool compared to average, then it would signal yet another reason to believe that changes are ahead for Atlantic activity next season.

Much of this was reflected in Dr. Phil Klotzbach’s first outlook for the 2016 hurricane season which was released last week. The December discussion indicates a 25% chance of seeing a hyper-active season in 2016 which would be a significant change in what we’ve seen in recent years. A lot will depend on exactly how much the El Niño weakens and how warm the tropical Atlantic manages to get before August-September-October rolls around.

Trying to put this all in to perspective, it is kind of like having a the #1 recruiting class in college basketball. Your team is loaded with incoming talent, maybe a couple of seniors with terrific skills to round things out. It appears that the next basketball season is going to be spectacular for your team. They might even have a chance to win it all and be National Champions. Along the way, things can happen: a torn ACL for your star forward. Coach gets sick during tournament play. Another player goes down with a broken hand. All of a sudden, your #1 team is now losing game after game and what looked like a sure-thing season turns out to be anything but. You just never know.

Hurricane season is much the same. It really is. There can be a plethora of signals for the Atlantic Basin to be very active and yet, when all is said and done, it wasn’t and no one really knows why until after the fact. Right now we are in the equivalent of the signing period of college basketball – when the top recruits begin to choose their college. We won’t know how things pan out until much later – maybe even during the season itself. Yet, much like college ball, I see potential building for a busy 2016 in the Atlantic. However, just because something might happen, doesn’t mean that it has to happen.

I’ll post an update to this blog in mid-January. By then, we will have even more data from the various climate models and the picture of what lies ahead will become just a little bit clearer.

M. Sudduth 10:15 AM ET Dec 14

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X marks the spot as tropics stay busy

NHC's Graphical Tropical Weather Outlook map showing several areas worth monitoring over the coming days

NHC’s Graphical Tropical Weather Outlook map showing several areas worth monitoring over the coming days

We are in prime time of the hurricane season and with the Atlantic Basin as warm as it is, it comes as no surprise really that there is plenty to talk about.

The NHC has several areas outlined this morning, including the remnants of TS Grace, that bear watching over the coming days.

First up, TS Henri is weak and is moving quickly now to the north. The forecast calls for a turn to the northeast as it transitions from a tropical storm in to a more spread out extra-tropical system over the far reaches of the North Atlantic. Seas will begin to subside in and around Bermuda where some beach erosion took place over the past couple of days due to the constant easterly swell that Henri was generating.

Henri could bring a period of heavy rain to parts of extreme southeast Newfoundland but the fast movement will limit the impact and its duration.

Next we have the remnants of tropical storm Grace moving towards the northern Leeward Islands. There has been a significant increase in deep convection with the system which could lead to periods of heavy rain and gusty winds as the low pressure area moves through. While there is little chance for it to become a tropical storm again, we know by now that rain alone is enough to cause major issues if too much falls at once. The forecast indicates that the remnants will track westward towards Puerto Rico over the weekend. We’ll have to watch and see what happens once the energy gets in to the southwest Atlantic or possibly the southeast Gulf of Mexico some time next week.

Off the coast of Africa is where the next large tropical wave is making its debut. The NHC is giving it a medium chance of development over the next five days and if it does in fact do so, it would be the 5th such development in the MDR or Main Development Region since late August. This is almost unheard of during strong El Nino seasons yet here we are, Danny, Erika, Fred and Grace all developed between Africa and the Lesser Antilles. This next system shows promise to become a hurricane over the open waters of the Atlantic in the coming days. As long as it remains away from land, so be it.

Finally, a small low pressure area has developed well to the southwest of the Azores Islands in the northeast Atlantic. It has only a small opportunity for development and of course wouldn’t be an issue for any land areas; something to watch but nothing to be concerned with.

To sum things up, there is plenty to keep track of but no major issues brewing in the tropics as of now. Enjoy the weekend, nice fall-like weather will be in store for much of the eastern part of the nation but then we return to the summer look and feel to things shortly, so take advantage of the cooler temps while you can! I’ll have a video discussion posted later this afternoon.

M. Sudduth 9:40 AM ET Sept 11

 

 

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