Pre-season storm forms way out in the Atlantic – but how & why?

TS Arlene

TS Arlene

We’re approaching the end of April and we have the year’s first tropical storm to track: Arlene.

First – a little history….

The Arlene of 12 years ago (wow, has it really been that long?) made landfall just west of Pensacola, FL on June 11 as a weakening but fairly well organized tropical storm. I was there along with colleague Mike Watkins (we began in Destin and made our way over to Gulf Shores, AL). The 2005 version of Arlene had plenty of warm Gulf of Mexico water to work with and had it not been for strong upper level winds, common in the early portion of the hurricane season, it would have easily become a hurricane. Check out this archive video from our 2005 documentary: TS Arlene in 2005 from our Tracking the Hurricanes: 2005 documentary

Fast forward 12 years and we have Arlene again. First of all, names get re-used unless they have a reason to be retired and replaced from the list. Think of Andrew, Camille, Matthew and Katrina as examples – major events usually mean a name will be replaced. So far, Arlene has not had such an infamous fate and this iteration of it will be no different.

However, what is fascinating is how Arlene formed and where it formed.

We know that tropical storms and especially hurricanes “like” warm water, say around 80F or so. While this is generally true it is not an absolute must-have ingredient. Warm, tropical water certainly provides more latent heat for a tropical storm or hurricane to tap in to but that is just one mechanism that we see to drive the deep convection that keeps the heat engine going. There are other ways to drive the thunderstorms around the center of circulation, even over cooler water such as what we are observing in the case of 2017’s Arlene where sea surface temps are close to 70F at best.

To better explain it, here is a quote from NWS meteorologist Tony Cristaldi:

“[to help you understand how]  a “true” TC is able to form over sub-26C (80F) water: That objective temp has a HUGE underlying assumption that temps aloft (500MB and up) are typical of those seen over the MDR during the traditional TC season. Obviously, Arlene, and other high(er) latitude systems, including “Medcanes”, feature not only colder SSTs/near surface air temps, but also much colder temps aloft. As long as the air mass lapse rates are conditionally unstable, there exists sufficient moisture, and wind shear is not prohibitive, then “tropical” type cyclone development can and does sometimes occur.”

Basically, the environment that created Arlene is unstable enough to allow the limited but persistent convection to wrap around the center and give us the true (albeit marginal) look of a tropical storm. Bottom line is that to get the powerful deep tropics hurricanes that we’re used to seeing, yes you need deep warm water, light shear and ample moisture in the mid-levels. For these out-of-season open ocean storms, not so much; Arlene being a prime example.

Does it mean a busy hurricane season ahead? I highly doubt it. The pocket of energy that became Arlene did not originate from the deep tropics but instead came from a mid-latitude source. If we were to see a true tropical wave emerge from Africa and manage to develop in to a tropical storm or especially a hurricane, then THAT would have significance. Instead, Arlene is just a novelty and something for shipping interests and weather geeks to keep watch of.

I’ll have a video discussion posted covering Arlene tomorrow morning.

M. Sudduth 10:55 pm ET April 20

 

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Let’s talk about water

Storm surge from hurricane Ike

Storm surge from hurricane Ike

When most people hear the word “hurricane” they more than likely think of one thing: wind. Next, they probably ask, “what category is it?” While these aspects of a hurricane are certainly important, I believe a larger issue is being overlooked and put on the back burner until it is too late: the threat from water.

We can see the wind or, more accurately, the effects of wind, as soon as it starts blowing. The harder it blows, the more dramatic the effects are on the things around us such as trees and flags. This registers instantly in our brains and we can understand it because we can see it. Therefore, if the hurricane has 100 mph wind, while you might not necessarily grasp the concept of just how much energy that means, you do generally understand that it could damage your property.

Water, on the other hand, is seemingly tougher to conceptualize. The forecast as a hurricane approaches calls for 10-15 inches of rain. What does that mean? We can all visualize a ruler which is 12 inches but what exactly is 12 inches of rain going to do at your home or business? A lot of that depends on how fast the rain rates add up and what the drainage is like in and around your property.

The real danger comes when too much rain falls too fast and streams and creeks become swollen, flowing over the roadways and inviting disaster. There is no way to predict when and where this will occur with any degree of accuracy. As we saw again with Matthew last October in North Carolina, despite repeat events (Floyd in 1999 and the historic rains in NC/SC in 2015) people continue to drive across flowing water as if they are immune to the laws of physics. Too often, they are dead wrong. I’ll come back to this topic later.

Storm surge is about as dangerous and destructive as it gets yet few people truly understand what it actually is. Historically, storm surge has taken more lives than any other effect and it is the sole reason that evacuations are ordered for coastal areas. That’s right, we do not evacuate for wind – it’s the water. While it is true that you do not want to remain in an unsafe structure during the high winds of a hurricane, modern building codes should protect a vast majority of the people in harm’s way but water is a different story.

Moving water has an enormous amount of force behind it. Waves crashing ashore bring with them enough energy to bulldoze structures along the immediate beachfront. Those crumbled structures now become solid pieces of the surge and waves and act to batter and break up even more man-made structures. The end result is massive damage along the coast and the potential for loss of life.

Instead of yammering on and on about how bad it can get, I want to focus on a solution. There is something that can be done to completely eliminate the loss of life that we are seeing because of hurricanes (tropical storms too) and the effects of water.

The first step is understanding the risk where you live. As I said, evacuations are planned based on potential storm surge flooding and this is done well in advance of any hurricane. You need to take the personal responsibility of asking questions about where you live or work. Do not rely on someone to do it for you. Use social media and the Internet as a whole to your benefit. Go online and ask, “Do I live in an evacuation zone?” Do not stop asking until you find the answer.

Once you know your risk to storm surge, you can then make an appropriate plan. Make the decision now that if your evacuation zone is called to evacuate, you do it, no questions asked. No waiting to see what the hurricane does tomorrow or what Bob and Margaret next door decide to do. This is your one chance to get it right and not regret it later. Do not put first responders at risk during the storm by calling them begging to be saved. That is irresponsible and selfish and should never be an issue if people followed the plan and left when told to do so.

While it is true  that most people who evacuate come home to little or no damage, it is best to err on the side of caution and leave when told to do so. I realize more than you know how stressful it is and that it is not something to be taken lightly. That is why I make the case for planning now and making the choice now that you will in fact go when told to go.  It takes planning and that needs to be done before hurricane season ever begins.

Truck driving on flooded road after hurricane Matthew in eastern North Carolina

Truck driving on flooded road after hurricane Matthew in eastern North Carolina

Fresh water flooding is a killing agent that seems to never get better. Time and again people are seen and captured on video trying to cross flooded roads – often times failing and losing their lives. This is absolutely unacceptable and needs to stop. Again, it puts rescuers at great risk and drains resources that could be used elsewhere.

I am going to make it real simple. Hurricanes and tropical storms mean rain and a lot of it. When it rains, roads flood. I don’t care what kind of vehicle you own or how many times you have been down “that road”, it doesn’t matter if the water is too high or too swift; you will get swept away. Don’t do it. Stay home and avoid driving until things get better.

As the hurricane season nears, I challenge you to do more to learn about the impact of water from tropical storms and hurricanes. Wind is the big headline but often times at the cost of losing sight of how water can be both deadly and destructive. We need it to survive but it can turn against us in nightmarish ways.

Technology can only get us so far. We can see the hurricanes before they even form thanks to incredible advances in computer models. Now it is time to put our common sense to use and realize once and for all that sometimes we have to relent and do the right thing. That means evacuating when told to do so and not driving across flooded roads. It’s 2017 people, let’s act like we’ve been here before and actually learned something from the past. If not, well, you know what happens if not….

M. Sudduth 2:15 PM ET April 12

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New hurricane documentary published

It’s been a few months since I have posted anything here. The reason? Been quite busy playing filmmaker. And now, the results of those efforts are revealed with the release of my brand new “Tracking the Hurricanes” documentary.

The first in the series was produced in 2004 after the big season that brought hurricanes such as Charley and Ivan. Then, I produced another segment after the historic 2005 season. It wasn’t until 2008 that I had enough material for another program and that was the last time…until now.

We’ve had hurricanes since 2008, that’s for sure but I just didn’t have enough to put together a full-length program. So, after the 2016 season, I figured it was time.

The result is a two-part series that spans 2009-2016 and takes you on a journey with us as we develop new technologies, including the weather balloon project: HURRB.

We also worked towards building a better unmanned camera system that would ultimately be put in to to use during hurricanes Hermine and Matthew in 2016. However, the technology has to be tested and we did so during winter storms and flood events in the face of a lack of U.S. landfalling hurricanes. Those efforts paid off and by the time we get to 2016, we were ready.

So here it is, part one of the new “Tracking the Hurricanes” series. I will post part two on Friday, March 3. Enjoy and please feel free to share with anyone!

M. Sudduth 1PM ET Feb 24

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Otto small but will bring torrential rain and strong wind to portions of Central America

The biggest hazard from Otto will be the rain which is expected to be more than a foot in some locations.

The biggest hazard from Otto will be the rain which is expected to be more than a foot in some locations. Click to view full size.

It is late in the hurricane season but TS Otto has managed to find a small corner of the Caribbean Sea in which to flourish. Recent reports from the NHC indicate that Otto is nearing hurricane intensity and by looking at satellite images, it won’t be long until that status has been achieved.

Fortunately, Otto is small in size with tropical storm force winds extending only 35 miles out from the center. When it becomes a hurricane, those winds will also be confined to a relatively tiny area near the center thus wind is really not going to be the issue here.

Instead, rain is my big concern. Heavy rain is expected to fall across portions of Nicaragua, Costa Rica and Panama today and lasting through the remainder of the week. The extremely slow movement of Otto will only add to this hazard and for areas of Nicaragua especially, rainfall could be excessive and lead to substantial flooding with great risk to life and property. Obviously interests in the region should be paying close attention to the progress of Otto and be ready to head to safer locations should flooding commence. I am very worried about the amount of rain that could fall with this system and will continue to emphasize that fact throughout this event.

Otto is expected to move slowly westward over the next few days and eventually make landfall somewhere in southern Nicaragua and possibly straddle the border of Costa Rica. This is very far south for a hurricane to be making landfall no matter what time of the hurricane season it it. As such, people are not used to this which makes it even more important for folks to keep up to date with the latest information as Otto progresses.

There is no risk of the storm turning north in to the Gulf of Mexico and even the NW Caribbean Sea due to mid-level high pressure building in across the region, acting like a block and forcing Otto to remain south and move generally westward underneath the high pressure area. It is possible that the remnants survive the passage over Central America and emerge in to the southeast Pacific – if so, we’ll deal with that when the time comes.

I’ll have more in my video discussion which I will post later this afternoon.

M. Sudduth 8:50 AM ET Nov 22

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TD16 forms in SW Caribbean – forecast to become a hurricane

TD 16 track map from the NHC. Note the slow movement over the next five days and the forecast for the depression to become a hurricane as it approaches Central America.

TD 16 track map from the NHC. Note the slow movement over the next five days and the forecast for the depression to become a hurricane as it approaches Central America.

Hurricane season officially ends on November 30 but before we get to that date, we will have to deal with one more hurricane, or so it appears.

The NHC began issuing advisories on TD16 early this morning. The depression is located in the southwest Caribbean Sea, not far off the coasts of Panama and Costa Rica. Overall the environment is generally favorable with warm water temps and a small region of upper level winds that are conducive for additional strengthening. As such, the depression is forecast to become a tropical storm (name will be ‘Otto’) later today and eventually reach hurricane intensity as the week progresses.

Weak steering currents for the time being will result in a very slow motion of the depression as it meanders over the SW Caribbean. In the longer term, enough mid-level ridging should build in to gradually push the would-be hurricane towards the west and in to Central America. Precisely where landfall occurs remains to be seen but interests in Costa Rica, Panama and Nicaragua should be monitoring this system very closely.

The main hazard will be excessive rain and I cannot emphasize this enough. While the wind speed will gradually increase it is the rain that concerns me the most due to the slow movement. Right now there are no significant impacts being felt on land since the depression is far enough off the coast. However, once it begins to move westward later this week, bands of torrential rain will rotate onshore across southern Central America and the potential for flash floods will increase, especially in any mountainous areas. I will address this issue more once the NHC updates their “hazards impacting land” section of the Public Advisory. For now, residents and visitors to the region should be mindful of this system and be ready for the possibility of life-threatening flooding as the system approaches later this week.

Outside of TD16, the Atlantic Basin is quiet as we would expect for the last third of November. The season turned out to be fairly busy and with soon-to-be Otto on the horizon, the Atlantic will end up over-achieving for the year with activity running a little above the long term norm. I will have a more in-depth discussion of the 2016 season in a blog post scheduled for November 30. For now, we will focus on TD16 and its eventual impact to Central America.

I’ll have more in my video discussion which will be posted later this afternoon.

M. Sudduth 8:15 AM ET Nov 21

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