When 80% is not enough

Wednesday, August 17 at 2pm ET the National Hurricane Center issued the first outlook on what would become probably the most talked about area of interest (invest) in the history of mankind. That outlook began a process that kept scores of weather geeks, emergency managers, TV meteorologists, weather forecasting firms and the general public glued to their Internet-connected devices. From the get go it looked like this could be “the one”. It had potential to make it all the way across the Atlantic and possibly affect the United States after roaring through the Caribbean. And so here we are at the other side of that long journey and what became known as “99L” to millions of people will long be remembered for what it didn’t do: failed to develop.

As the process of tracking the tropical wave got underway, computer models were generally in agreement that the system would move westward at a fairly low latitude. However, it was clear early on that mid-level dry air, somewhat associated with the Saharan Air Layer (SAL), would be an inhibiting factor for development. Never the less, by early Saturday morning the 20th, it looked as though a tropical depression would form. Chances went from virtually nothing to 50% in just three days.

By Monday evening the 22nd, the probability increased to 60% and it looked as though a hurricane was possible for the southwest Atlantic Basin, maybe even close enough to Florida or the Carolinas to warrant concern. The social media hurricane machine was in full throttle mode with every expert (and non-expert) opinion you could imagine being thrown in to the mix. It was “invest 99L” overload and it would only get worse.

Leading the charge for development at first was the dynamic duo of the GFS and the ECMWF. Both seemed to latch on to 99L and make something of it. At first, it looked like a track towards Florida and then a turn north was likely. At times, the GFS had an enormous hurricane sitting not too far off the North Carolina coast, moving harmlessly out to sea in the longer term. It looked like this would be a close call but no guarantees yet for a landfall.

As the days went by, seemingly very slow considering we can watch the computer models come and go virtually 24 hours a day, things began to change. The GFS dropped the development almost completely while the ECMWF put memories of Katrina, Andrew and Betsy in our collective minds. It wasn’t just the Euro, the new and improved HWRF model, which is specifically designed to forecast tropical cyclones, showed similar forecasts of a hurricane headed towards south Florida and then turning west as it tracked south of a strong high pressure area over the mid-Atlantic. The hurricane world went in to full meltdown mode. It had been since before Twitter, Facebook as we know it, the iPhone and even the birth of One Direction that Florida had been hit by a hurricane. It was Tuesday, August 23 and 99L had a 70% chance of developing in to at least a tropical depression. The “H” word was bound for Florida.

To make matters worse, the ECMWF ramped up 99L to beast mode and sent it towards Louisiana, the LAST PLACE that needs a hurricane this season. Meanwhile, the GFS showed almost nothing at all. Just weak energy coming across and never really doing much. People were scoffing that if the Euro was right, congressional hearings needed to take place immediately to “fix the GFS!”. It was pure madness because, you know, the ECMWF nailed Sandy’s forecast from 8 days out. People were hung up on a hurricane from four years ago, forgetting the failures of even recent events like Erika last season and Fiona in 2010. Oh yeah, let me tell you about that one.

In 2010, we had Earl, headed for a possible landfall up the East Coast. Meanwhile, the ECMWF was advertising Fiona to be “the next Katrina”. A few in the weather business bit off on this and ran with it like the end times were coming. Earl was going to be a dud while Fiona would be a disaster of epic proportions. All the while, the GFS showed Earl doing exactly what it ended up doing: coming close to the NC Outer Banks then turning out to sea as a strong hurricane. As for Fiona, the GFS showed it as nothing more than a nuisance and that’s how it all turned out. GFS right, Euro wrong. Funny how few people remember that. I remember, trust me, I was on the Outer Banks where Earl brought 85 mph wind gusts to our anemometer that was set up next to Oregon Inlet.

By Wednesday morning, just 48 hours ago, the chance for 99L to develop made it to 80%. It looked like a sure thing now. I mean 80% is pretty good, right? In basketball an 80% free throw shooter is considered to be almost lethal from the line. You foul that player and you might as well put two points on the board. Eight times out of ten the shots go down.

But what happens when that player is in the title game and his team is down 1 with .90 seconds on the clock and he is fouled driving to the hoop? Everyone holds their breath as he lofts the first shot to tie the game. He misses. It’s stunning. The announcers balk about his percentage and how they can’t believe he missed. Must be the immense pressure. Time for try number two. He misses. No one gets the rebound and the clock expires. His team loses the National Championship for one simple reason: 80% is not enough. It’s not 100%. There was a 20% chance he missed either of those two shots. Now this is purely hypothetical but it makes my point. Sometimes high probability is mistaken for certainty.

In the case of 99L, it looks dead and gone now. The GFS, in its past few days of runs, turned out to be correct, for the most part. No hurricane coming for south Florida this weekend like the Euro showed. To be fair, the HWRF did as well and it busted big time. Instead, the Euro now has weak energy bringing possible heavy rain to portions of Florida. No hurricane in to Louisiana or elsewhere, just a strung out mess.

Odds of development over the next five days are down to 60%. Strong wind has all but beat the system in to oblivion. There is virtually no convection or thunderstorm activity with it and the USAF Hurricane Hunter crew has been grounded since there’s nothing there to investigate.

Sixty percent. Hmmmm. That’s not too high nor is it very low either. What is the reason behind this number? It’s because there is still a chance, apparently a 60% chance as of this writing, that 99L will develop some in the Gulf of Mexico. How could this be? The Euro “dropped it”. Well, the ever-excited HWRF sure didn’t and the GFS now shows limited development in a few days with some rather wacky tracks thrown in for good measure. To be honest, it’s giving me a headache to watch this day in and day out and all we have is an area of interest, even if fading to an area of blue skies.

I caution that while the gist of my post is aimed at pointing out the obvious, that anything short of 100% probability has a chance of falling short, it is also true that unless it’s zero, there’s still a chance. Even the 60% free throw shooter is sometimes the hero.

There is still some energy down in the region near the southeast Bahamas that might be able to survive long enough to warrant keeping an eye on. None of the computer models that show any development potential do so until later in the weekend – so let’s see what happens. Perhaps 80% was too high early on but 60% will be just enough for now.

We want to be able to trust the computer guidance to give us time to prepare if in fact something is going to develop. However, the public should understand probability and know the limitations of forecasts even in the relative short term. Most people don’t have time or interest to fully invest their energy in to making sense out of it all. I do my best and could not for the life of me understand why the GFS gave up on this system while the Euro did not. Sometimes you need to look out the window, so to speak, and view the actual weather and not just the predictions. The satellite presentation of 99L never really looked promising for development. It came close a couple of days ago but the reality was it didn’t have that “look”. So logic should have dictated that if it looks poor and one of the major global models insists on non-development, then maybe that’s why: because it won’t. It’s a simple concept and for now, it turned out to be right. Shear and lack of convection and overall organization has kept 99L from developing but it’s not necessarily over.

I think the next 48 hours will be all we need to know how this ends. If nothing happens by then and the wave of energy basically spreads out or dissipates completely, then we’re golden. Until that happens, it’s obviously prudent to keep an eye on things – just in case 60% is just enough to do what 80% could not.

I’ll have more in my daily video discussion posted here, to our app and on YouTube later this afternoon.

M. Sudduth 9AM ET Aug 26

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Deep tropics closed – so we look west, closer to land

Recent satellite photo showing the areas of interest, and the shut-down eastern Atlantic

Recent satellite photo showing the areas of interest, and the shut-down eastern Atlantic  (click for full-size image)

Another large, suppressing surge of dry, stable air is moving off of Africa as of late and this will all but shut down the chance for development in the deep tropics – at least for now. With the eastern Atlantic out of play, where might we look for possible development over the coming days? The answer: farther west, closer to land areas.

Before I get in to what may be coming down the road, let’s look at the latest on Earl, which is still alive and somewhat well in the Bay of Campeche.

After making landfall in Belize, Earl managed to remain intact as a tropical storm as it moved across the Yucatan peninsula. It is now situated over the extreme southern portion of the Bay of Campeche and remains at tropical storm strength. The main threat to land will be continued heavy rain along with some gusty winds. The storm will make landfall again this evening in Mexico and begin to dissipate.

Something interesting will happen after landfall with Earl. It seems that energy from the storm will survive the terrain of Mexico and merge with a disturbance over the southeast Pacific, just off the coast. The NHC indicates that all of this will result in the formation of a low pressure area that is likely to become a tropical depression over the next few days. Since this will be happening so close to land, interests along the Pacific side of Mexico should be monitoring closely. Heavy rain is likely and eventually a tropical storm may form and affect the southern Baja peninsula.

Meanwhile, a complex situation is developing in the northeast Gulf of Mexico that bears watching. The NHC mentions that a trough of low pressure is forecast to develop over the warm waters of the northeast Gulf this weekend. This focal point for showers and thunderstorms could lead to the potential development of a tropical depression at some point. The longer it remains over the water (and farther out from land) then the higher this chance becomes.

Rain forecast for the next seven days showing an alarming amount for portions of the northeast Gulf Coast region. This will change and evolve over time but this gives you an idea of how much is forecast by the computer models.

Rain forecast for the next seven days showing an alarming amount for portions of the northeast Gulf Coast region. This will change and evolve over time but this gives you an idea of how much is forecast by the computer models.

One thing that seems almost certain is that an incredible, dangerous amount of rain is setting up for portions of the Gulf Coast states – mainly from southeast Louisiana eastward in to Florida. In fact, some of the rain totals that are being suggested by computer models are astounding. This is something that needs to be watched very closely. Even if nothing develops in terms of a tropical depression or more, the rain by itself will be a major problem.

Next we have the energy associated with what was once 96L and another tropical wave coming in from the east. While there is not much to look at now, there is some evidence in the computer models to suggest we see development in the southwest Atlantic in a few days. I do not see any indication of anything strong at this point, just something to watch since we are in August and the water temps in the western Atlantic are so very warm.

All in all, it looks to be an interesting few days ahead. The east Atlantic won’t be an issue at all due to the strong SAL or Saharan Air Layer that is dominating the region. So we must look closer to home, so to speak, and with that we do see a few areas of potential trouble brewing. I will add more with my daily video discussion to be posted later this afternoon followed by another blog update here tomorrow morning.

M. Sudduth 11:45 AM ET Aug 5

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Earl headed for landfall in Belize, hurricane conditions likely

Satellite image of strengthening tropical storm Earl in the western Caribbean Sea

Satellite image of strengthening tropical storm Earl in the western Caribbean Sea

There’s not much to say about Earl this morning. The tropical storm continues to strengthen and is almost a hurricane. Air pressure is down to 989 mb and the winds have increased to 70 mph. It won’t take much to have the first hurricane of the season (there was a hurricane in January but I don’t count that one as being in the season for obvious reasons).

For residents and visitors in Belize, the impacts will depend on just how strong Earl gets before landfall. There is still time over the very warm western Caribbean for it to strengthen and it seems almost certain that it will become a hurricane.

Aside from the heavy rain that will accompany Earl, the NHC mentions storm surge of 3-5 feet above normal tide levels impacting areas to the north of where the center makes landfall. This is not severe but enough of a danger to be taken very seriously.

I am not as concerned about the wind right now – assuming Earl becomes a category one hurricane, those winds can be dealt with as long as people use common sense and stay out of harm’s way. My concern is the heavy rain and coastal storm surge. We lose more people to water than wind – by far.

Once the 11am NHC advisory is issued, I will produce a video discussion covering the impacts that Earl are likely to bring to the region. I’ll post that here, in our app and on our YouTube channel.

M. Sudduth 10:05 AM ET Aug 3

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Tropical storm Earl forms south of Jamaica, headed towards Central America

Recent close up satellite photo of newly named TS Earl. Notice the overall disorganized appearance of the storm. This could help to keep it weaker as it approaches the southern Yucatan peninsula in a couple of days.

Recent close up satellite photo of newly named TS Earl. Notice the overall disorganized appearance of the storm. This could help to keep it weaker as it approaches the southern Yucatan peninsula in a couple of days.

It took a little longer than expected, but invest area 97L has developed in to tropical storm Earl. The Hurricane Hunter crew flew in this morning and found a better defined low level circulation center and sampled winds strong enough to classify the system as a tropical storm.

So what happens next? Well, for the most part, it’s a fairly easy forecast track-wise. Strong high pressure over the Lower 48 will keep Earl pushed south of the Gulf Coast states. This means it will track in to Central America, perhaps somewhere in Belize, along the southern extent of the Yucatan peninsula. Landfall looks to be in about 48-60 hours, depending on how the forward speed changes over time.

Once over land, it is possible that Earl will remain on a track far enough south to avoid even the most southern part of the Gulf of Mexico, what we call the Bay of Campeche. Some models show this scenario, others pull it farther north with a second landfall in Mexico several days from now. We’ll just have to wait and see but for now, the focus will be on the Yucatan, especially Belize.

As for intensity, that’s an entirely different story. Top winds are 45 mph now but Earl is not very well organized. I do not see any significant spiral banding, more of a blob of convection trying to hold on near the low level center. This is due to stronger upper level winds pushing on this mass of thunderstorms, keeping from aligning perfectly over the center. As long as this remains the case, Earl won’t strengthen much. However, if the shear relaxes enough, and the system can stack itself and allow a ring of convection to develop around the center, then it has a chance to become a hurricane. Water temps are extremely favorable in the region with plenty of upper ocean heat content. Indeed, residents and visitors in Belize and elsewhere along the east side of the Yucatan need to be paying close attention to Earl.

I will have a full breakdown of the forecast for TS Earl in my video discussion which will be posted early this afternoon. In addition, follow @hurricanetrack on Twitter for more frequent quick posts with new information, satellite photos and more.

M. Sudduth 11:55 AM ET Aug 2

 

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Tropical storm forming in the Caribbean Sea – will be named Earl, track towards Jamaica, Yucatan

Invest 97L well on its way to becoming a tropical storm later today as convection and overall organization increases

Invest 97L well on its way to becoming a tropical storm later today as convection and overall organization increases

The difference between yesterday and now with invest area 97L is impressive. Satellite images show a much better defined area of deep thunderstorms or convection and improving outflow in the upper levels of the atmosphere. The NHC is reporting that winds are already over tropical storm force and that a surface circulation is becoming better defined. It won’t be long now until we have a tropical storm to track – its name will be Earl.

As I have mentioned several times already, water temps in the Caribbean, especially the western portion, are exceedingly warm. Once this storm forms, there won’t be much to hold it back from strengthening up until land interaction in a few days.

As for today, squally weather will begin to impact Jamaica and the Cayman Islands with fringe effects continuing for portions of Hispaniola. By tonight, it is possible that tropical storm conditions will be felt in Jamaica coupled with very heavy rain. The island needs the rain, so as long as it won’t be too much in too short a time period, what would be Earl could bring beneficial moisture to the area.

Track forecast models showing a fairly tight overall path for what would be TS Earl - headed generally towards the Yucatan peninsula and southern Gulf of Mexico

Track forecast models showing a fairly tight overall path for what would be TS Earl – headed generally towards the Yucatan peninsula and southern Gulf of Mexico (click to enlarge)

Strong high pressure to the north of the developing storm will keep it moving generally westward over the coming days. This will not allow the would-be storm to track in to the Gulf of Mexico – at least not until after crossing the Yucatan peninsula. Interests along the east side of the Yucatan need to be monitoring the progress of this system closely. It is possible that this system will go on to become a hurricane, especially considering the very warm water and high amounts of upper ocean heat content in the western Caribbean.

After passing over the Yucatan, depending on how far north the system would be, it could enter the southern Gulf of Mexico and strengthen again before making landfall well south of Texas. We can wait and see how well organized it becomes between now and landfall along the Yucatan before worrying too much about these details. Obviously the more time over land it spends, the harder time it will have intensifying again later on.

Elsewhere in the tropics, the east Pacific refuses to shut down. We now have TS Howard well off the coast of Mexico. It is moving northwest and towards cooler water and a more stable background environment. Howard should not pose any threat to Hawaii and will eventually die out over the open Pacific.

It is now August and in about two weeks, the rapid rise towards the peak of the season begins. If 97L goes on to develop in to a tropical storm and then a hurricane, it would put the season well ahead of where we should be for this time of year. Water temps in the Main Development Region and elsewhere across the western Atlantic are very warm. I have seen several indications that the next 45 to 60 days or so will be very busy in the Atlantic Basin. It’s never a guarantee one way or another, but the signs are difficult to ignore. It’s not the kind of season to sluff off and hope that nothing happens. With no El Nino and its associated strong shear machine cutting across the Atlantic, I feel as though we are in for a busy time going forward. If ever there was a season to be prepared compared to the last few, this is it in my opinion. If I am wrong, everybody on the coast comes out a winner. If I am right, and it’s not like I see this and no one else does, then hurricanes will be making headlines once again for the United States and elsewhere across the western Atlantic Basin.

I will have continuing coverage of 97L with frequent updates posted to Twitter (@hurricanetrack) throughout the day. I will also post a video discussion early this afternoon as well. Follow along in our app too, it’s on the App Store, search Hurricane Impact – all of my Tweets, blog posts and video discussions are posted to the app instantly. Get it and have everything all in one place!

M. Sudduth 10:30 AM ET Aug 1

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