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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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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TS Kate forms but will have little overall impact

Visible satellite picture showing TS Kate in the central Bahamas

Visible satellite picture showing TS Kate in the central Bahamas

The 2015 hurricane season now has its 11th named storm, Kate. The NHC made the upgrade this morning citing 40 mph winds with a pressure of 1008 mb. Kate is moving towards the northwest but will eventually turn out in to the open Atlantic head of an approaching trough.

Right now, the storm is impacting portions of the Bahamas where tropical storm warnings are in effect. However, much of the inclement weather associated with the storm is located to the east of the low level center, leaving much of the Bahamas free of any significant impacts.

Water temps along the track can still support a hurricane but the upper level winds should prevent that from happening. The official NHC forecast calls for some additional strengthening and Kate could reach 50 mph before being absorbed by a larger storm system emerging from the East Coast later this week.

There might be a period of increased swell activity for parts of the Southeast and East coasts which could lead to additional beach erosion issues during times of high tide as the week wears on. Outside of that, I see no reason to worry about Kate along the United States coast.

I’ll post a video discussion covering the latest on Kate this afternoon.

M. Sudduth 8:50 AM ET Nov 9

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One more storm before season ends?

Latest tropical weather outlook map indicating a couple of areas to watch over the coming days

Latest tropical weather outlook map indicating a couple of areas to watch over the coming days

November is typically a quiet month in the tropics and in fact, it is extremely rare for there to be a November hurricane threat to the United States. Cooler near-shore sea surface temperatures combined with increasingly stronger upper level winds usually keeps a lid on things – but not always.

During the last few weeks of the hurricane season, we look to the Caribbean Sea and southwest Atlantic for the best chances of development. Right on cue, both areas have something to monitor over the next few days.

The first area of interest is a broad area of low pressure tucked in to the northwest Caribbean off the coast of Belize. While it looks fairly impressive on satellite imagery, the forecast calls for it to move inland over the Yucatan soon and then over the southwest Gulf of Mexico by this weekend. Although water temps are warm enough in the region, strong upper level winds ahead of an approaching cold front, combined with land interaction, should limit development. Heavy rain and periods of gusty winds are possible as the tropical low moves across the Yucatan over the next day or two.

Recent satellite photo showing two distinct areas of clouds, showers and thunderstorms in the Caribbean Sea

Recent satellite photo showing two distinct areas of clouds, showers and thunderstorms in the Caribbean Sea

Meanwhile, another tropical wave has flared up as it enters the eastern Caribbean Sea. This is the second area that the NHC mentions on their latest outlook. It has a slightly better chance of development over the next few days and this is shown by most of the reliable global computer models. It is possible that this system could eventually become a tropical storm over the southwest Atlantic sometime next week. So far, with the exception of heavy rain and gusty winds spreading in to the Lesser Antilles, there does not appear to be any significant threat to land from this feature. It will be something to monitor but as I mentioned earlier, hurricane threats this late in the season are few and far between.

The eastern Pacific has returned to being very quiet for the time being. After super-hurricane Patricia, this is definitely great news. Water temps are still very warm off of Mexico and Central America and even though the season usually slows down in this region during November, it would not surprise me in the least if we saw one more storm or hurricane develop somewhere in the extreme southeast Pacific before all is said and done. For now, nothing is brewing but the pattern suggests that perhaps that will change in the longer term.

I’ll have more tomorrow.

M. Sudduth 8:30 AM ET Nov 5

 

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Hurricane Patricia a record setting event

It’s been quite a year for tropical cyclones globally. After several years in a row with few intense hurricanes and typhoons, 2015 has seen a remarkable turnaround. The latest is Patricia, now poised to strike Mexico near Manzanillo later today, and it is about as intense as they come.

There is not much I can say in terms of preparedness actions. Simply put, people in the path of this hurricane need to leave, period. If they haven’t done so already, they need to get moving. That being said, there’s actually some good news.

Patricia is NOT a 100 mile wide or 60 mile wide EF-5 tornado. I’ve seen people saying this on social media and it’s just wrong. Let me explain…

A hurricane like Patricia is very rare, obviously. One thing we do know because of the recon flights that have provided incredible in-situ data is that the radius of maximum winds (RMW) is very narrow. In fact, the ENTIRE extent of hurricane force winds, 74 mph to 200 mph in this case, is ONLY 30 miles from the eye. This is extremely important because it limits the amount of real estate that will have to deal with those winds. In other words, if you live just 40 miles from the eye, you would hardly notice as the core passed by. Move 20 miles closer to the eye and it’s a terrifying siege of flying debris and flesh-stripping wind. So while it will be awful for those who have to endure the core, it’s not like we’re talking about 100 miles of coastline laid to waste.

Another aspect of the small RMW is the storm surge. Katrina had a storm surge of 28+ feet in some locations due to its enormous RMW – more than 90 miles at one point. The result was a surge of water pushed onshore from Louisiana to Florida. In the case of Patricia, it will be a small area, maybe 10 to 20 miles, that receives a possible catastrophic storm surge. Wind drives the surge and the wind is only 200 mph very close to the eye.

I bring this up because it is important to keep the facts straight and not let the historic moment become clouded with information that is simply incorrect. Patricia is bad enough on its own and for those who remain in its path, today will be one not soon forgotten.

Texas to receive Patricia remnants

What happens after Patricia makes landfall? First, it will weaken extremely fast over the higher terrain of interior Mexico. Sadly, there will be potential for loss of life due to the flash flooding and mudslides as the torrents of rain impact those same mountains.

Info-graphic concerning the threat to parts of Texas from the remnants of hurricane Patricia

Info-graphic concerning the threat to parts of Texas from the remnants of hurricane Patricia

Interestingly, it looks as though the low level center will be stripped away but the mid and upper level energy will remain fairly intact. This means that there is a slim chance that once the remnants reach the warm Gulf of Mexico, some regeneration could take place. While this is NOT being forecast by the NHC right now, it would not surprise me to see it happen over the weekend or on Monday. What is more likely to happen is that Patricia’s energy leads to more of a non-tropical low pressure area to develop and bring gale force winds and extremely heavy rains to a large part of Texas. All of this will combine with a frontal boundary draped across the region and will help to focus the moisture feed, dumping excessive rain over a large swath of Texas.

In addition to the rain, coastal flooding is a real possibility with the strong onshore flow that is forecast to develop. Water levels could rise several feet in typical flood-prone areas away from the Galveston Seawall. In short, Patricia will leave a mark, even if only indirectly, long after its historic landfall in Mexico.

I will have a video discussion posted this afternoon that will highlight the landfall of Patricia and what to expect after tonight for Texas and vicinity.

M. Sudduth 9:40 AM ET Oct 23

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