False alarm looking likely for 99L but tropical wave off Africa, 90L, is on its way to developing

99L and its proximity to the Saharan Air Layer compared to 90L to the east.

99L and its proximity to the Saharan Air Layer compared to 90L to the east.

It has been an interesting few days to say the least. A lot of attention was placed on invest area 99L in the eastern Atlantic. By all accounts, it looked like it had a good chance of becoming a tropical storm and possibly even a hurricane. Long range models suggested a possible landfall somewhere in the United States, others did not. It was back and forth but the bottom line appeared to be that “Gaston” was destined to form from this large, sprawling tropical wave.

I guess that’s what probabilities are all about. Unless it’s 100%, it’s not a guarantee – ever. The highest probability that I saw from the NHC regarding 99L developing in to a tropical depression or stronger was only 60%. That’s notable but not very high compared to say, 90%. In this case, for the next few days anyway, it looks like the 40% portion will win out and 99L will not develop much further.

I think the reason can be attributed to the large size of the tropical wave. It needs a lot of energy to keep going and to thrive. Right now, despite warm water temps, the atmosphere just isn’t providing. The ever-present Saharan Air Layer might be playing a role as well. But how can that be? Invest area 90L, which is just off the coast of Africa, is almost a shoe-in to become a tropical storm early next week. Isn’t its proximity to Africa enough to keep it from developing? One would think, after all, looking at the SAL analysis map I have posted here, you can see there is much more dry air and dust to the north of 90L than is surrounding 99L to the west. I just don’t know sometimes but the end result is that while we certainly won’t ignore 99L, it doesn’t look like much of an issue for now. It should bring some showers and thunderstorms, along with gusty winds at times, to portions of the Lesser Antilles early next week but beyond that, no development seems like the most likely outcome right now. We will see what happens when the energy makes its way in to the southwest Atlantic later next week. Until then, 99L will not become Gaston.

That leads me to discussing 90L which, as I mentioned, is situated just off the African coast, not far off from Senegal. The NHC and indeed most of the computer guidance, is telling us that 90L will go on to develop over the coming days. And true to what I posted yesterday about how soon systems develop and how that relates to their eventual impact to land, it looks as though the track will be out over the open Atlantic. Indeed, the sooner they develop, the less likely they are to ever reach the United States or other land masses in the western Atlantic. We can’t say for sure that this will have zero impact but odds are it will be a big ACE producer (that is the measure of energy output from tropical storms and hurricanes during a single season) and little more.

The negative phase of the MJO, outlined in red, dominates the Atlantic Basin right now. Unless this changes, hurricane development will be tough to come by.

The negative phase of the MJO, outlined in red, dominates the Atlantic Basin right now. Unless this changes, hurricane development will be tough to come by.

One other note. The lack of uplift or what we call upward motion is probably also partly aiding in the anemic look to the Atlantic Basin as of late. The favorable phase of the Madden-Julian Oscillation, which is a fancy way of saying that widespread favorable conditions exist, is no where near the Atlantic right now. In fact, it seems semi-stuck over in the west Pacific where a couple of storms spin off the coast of Japan. Tropical storms and hurricane can form without the MJO being favorable but its enhancing effects really seem to help when it is present. So far, none of the long range models show it reaching the Atlantic Basin anytime soon. This could make it tough to see much in the way of hurricane activity except in certain spots where favorable conditions exist – but those will be few and far between.

M. Sudduth 9:40 AM ET Aug 21

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Colin product of favorable time period, likely not sign of hyper-active season

This map shows the favorable upward motion or MJO pulse (green areas) that helped to support the development of TS Colin

This map shows the favorable upward motion or MJO pulse (green areas) that helped to support the development of TS Colin

Tropical storm Colin, or what ever it is right now, is moving quickly northeast just south of the North Carolina coast near Cape Fear. It will continue this track and may strengthen some over the warm waters of the Gulf Stream but it won’t matter much since the effects will be well offshore.

Many references were made of the fact that Colin was the earliest we had reached the 3rd named storm in a season. Some may even point to this as evidence that the 2016 hurricane season will be quite a bit busier than thought. Here is why that makes little sense.

First, Colin was the product of a very favorable upward motion pattern in the Western Hemisphere. This is also known as a favorable MJO period or Madden-Julian Oscillation. Essentially, it is a period of time during which tropical convection or upward motion is enhanced for a certain region of the globe. It just so happens that during the past several days, our part of the world was favored. The result is tropical convection that often leads to the development of tropical cyclones. In this case, it did and did so in the climatologically favored areas of the Atlantic Basin. In other words, the pattern supported the development of Bonnie and Colin, nothing more, nothing less.

For the sake of argument, had Colin originated from a tropical wave in the deep tropics, then we would have some concern that the season will be busier than current conditions indicate. Tropical waves usually don’t develop that far east until much later in the season. In this case, Colin had its genesis in the western Caribbean, right where it should be for this part of the hurricane season. So far, there is nothing to make me think that this is a sign of things to come. Yes, it will probably be a busy season, considering we have had very little to track since 2012. Even an average year will seem busy at this point.

Also note that we had an anomaly back in January with what turned out to be hurricane Alex. Again, this was just a random event where by the pattern allowed a very rare January hurricane to develop but it did so outside of the deep tropics and under very different circumstances than we would look for during the normal part of the season of June-November.

While it may seem like we are off to a record-setting pace, I think things will calm down after Colin. We might see something try to develop in the western Gulf of Mexico, almost in to the Bay of Campeche, during the next 10 days, but after that, the season will likely go in to a lull until the main event in August, September and October.

Meanwhile, TD One-E (for East Pacific) is meandering around just off the coast of Mexico nearing the Gulf of Tehuantepec where it should die out due to unfavorable conditions. However, the threat of heavy rains still exists for parts of the region and this could result in flash floods and mudslides, a common hazard from all tropical cyclones regardless of intensity.

I will say this: I find it interesting that the Atlantic Basin has produced two tropical cyclones during the season (Bonnie was technically just before the start) while the east Pacific is lacking somewhat. This is usually not the case as the east Pacific tends to be more active early on. In fact, last year, the east Pacific had record activity while the Atlantic was virtually shut down except for powerful hurricane Joaquin in early October. This might be a sign that at least the balance of energy is shifting from the Pacific and in to the Atlantic. We’ll see….time will tell.

M. Sudduth 8:40 AM June 7

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Quiet time short-lived? Some model support for Gulf development

Substantial MJO pulse forecast by the ECMWF over the next two weeks

Substantial MJO pulse forecast by the ECMWF over the next two weeks

The rest of this week is likely to remain nice and quiet across the Atlantic, Caribbean and Gulf but once we get to next week, things could change. Here’s why…

First of all, the time of year supports Gulf of Mexico or western Caribbean development. We shift away from the Cape Verde region and the waters between there and the Lesser Antilles towards a pattern that favors development much closer to land areas. We might be seeing that come to fruition in the coming days.

The other reason I think development could happen is the progression of a strong MJO or Madden-Julian Oscillation pulse. Think of it as a period of fertility in the tropics. Instead of dry, sinking air, the MJO typically brings with it an increase in convection and a general rising motion in the atmosphere. These things are needed to even have a chance for a tropical storm or hurricane to develop.

According to the GFS and the ECWMF, the MJO is about to amplify significantly in to the phases that would, in theory, support development either in the southeast Pacific or the western Caribbean/Gulf of Mexico regions.  Water temps are plenty warm and so now it’s just a matter of watching to see what happens. So far, both the GFS and the ECMWF show signs of developing a tropical storm in the 8 to 10 day time frame. For what it’s worth, the two models are in remarkable agreement on the timing and the general placement of such development – the southern Gulf of Mexico. I usually don’t pay much attention to model forecasts beyond the 5 to 7 day time frame but when the two (rival) models are in agreement, it is worth watching a little closer.

Right now, nothing to worry about at all. It’s important to remember that we are still very much in hurricane season and it’s not over until it’s over. There are signs beginning to come in to focus that we might have one more system to deal with before all is said and done. Obviously I will keep a close eye on how things shake out over the next week or so.

I’ll have more here on this tomorrow.

M. Sudduth 8:35 AM ET Oct 14

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Pacific about to get very, very busy while Atlantic remains closed

A very strong MJO or Madden-Julian Oscillation pulse is setting up across the tropical Pacific and once it reaches its full potential, we are likely to see a string of tropical cyclones develop.

The MJO is an interesting phenomena which is best described for the sake of simplicity as a period of fertility in the tropics. Think of upward motion as being “good” for development and downward motion as being “bad” for development. The more the air can rise and spread out evenly, the better the odds for tropical storms and hurricanes (typhoons) to get going. Conversely, if the air is sinking, this literally suppresses tropical convection and makes it very difficult for tropical cyclones.

Satellite photo of the Pacific where a strong MJO pulse is leading to an increase in tropical convection and eventually, numerous tropical cyclones

Satellite photo of the Pacific where a strong MJO pulse is leading to an increase in tropical convection and eventually, numerous tropical cyclones

Over the next couple of weeks a very favorable period for the tropical Pacific is likely. The major global models are indicating a very strong MJO signal and you can actually see it starting in the hemispheric satellite that shot I’ve included. The gathering of clouds just north of the Equator is no accident and fits in nicely with the coming MJO pulse.

As a result, the models are showing several tropical cyclones developing over the coming days across the Pacific. There are likely to be a few that reach incredible intensity, mainly due to the abnormally warm water across the region (El Nino).

Interests across the Pacific should be monitoring conditions as we enter this period of increased tropical cyclone activity. Even Hawaii has a chance for at least some impact once the central and east Pacific enter the favorable phase of the MJO – which won’t be too far off.

In the other basin, the Atlantic, things could not be more hostile. Dry, sinking air along with very high levels of wind shear (the change of wind direction and speed as you go up in the atmosphere) is literally keeping a lid on development chances. We typically do not see much during most of July anyway but right now, conditions are especially unfavorable and should remain that way for the next week or so at least.

Enjoy your 4th of July along the U.S. coast with no worries from the tropics. If you’re in the Pacific, as I mentioned, keep an eye on things over the next several days as the MJO ramps up and creates very favorable conditions. I’ll post another update here over the weekend to address any significant development that does occur in the Pacific.

Be safe this holiday period and I’ll have more this weekend.

M. Sudduth 11AM ET July 2

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Despite coming favorable MJO signal, not much to track as we get in to last month of season

Early November development points over the past 100 years indicating that the western Caribbean Sea is the most likely area for development

Early November development points over the past 100 years indicating that the western Caribbean Sea is the most likely area for development

October will end very quietly as there are no areas of concern in the Atlantic Basin this week. What about November? The last 30 days of the season are almost here – so what can we expect?

We typically look for development in the western Caribbean where the most concentrated development points over time are seen. However, it is possible get development all over the sub-tropical Atlantic, far from land. Even the east Pacific remains fairly active during November but overall, things begin to really slack off in both basins.

If we do get development in the Atlantic Basin during November, the most likely track is northeast. Sometimes, we do see a blocking ridge of high pressure set up over the Gulf of Mexico, sending anything that gets going westward in to Central America. All in all, November is normally pretty quiet.

As for this November, well, there is at least a small chance of seeing something develop in the Caribbean Sea over the next couple of weeks.

ECMWF forecast MJO activity showing favorable conditions setting up as we get in to November

ECMWF forecast MJO activity showing favorable conditions setting up as we get in to November

The MJO or Madden-Julian Oscillation is forecast to be quite favorable for upward motion as we get in to the first part of the month. Both the ECMWF and the GFS models show this trend. Looking at the long range model runs, nothing really seems to come along to take advantage of this more favorable upper level pattern. Sure, one run of the GFS may show a tropical storm forming in the long range but it gets dropped during the next run, only to pop up again later on. This inconsistency leads me to believe that we will not see much happening over the next week and probably longer.

There are a couple of fairly strong tropical waves moving across the deep tropics and these will likely impact the Lesser Antilles and other parts of the Caribbean Sea in the coming days. It is possible that one of these could try to develop as the favorable upward motion pattern sets in but again, the global models do really indicate much happening.

We are almost out of the season and one that was originally forecast to be extremely busy with a lot of potential hurricane activity. I know many people are wondering, with a smile on their face, what happened. While I do not know for sure, I have some ideas and will be putting together a special blog post about this for next Monday. I think seasonal forecasting is important as it could lead to better long and medium range forecasting which in turn can greatly reduce the impacts of hurricanes in the future by providing adequate lead time to prepare. I will delve in to this subject quite a bit as I work on this special post coming up for next week. Until then, enjoy the quiet pattern.

M. Sudduth 1:50 PM ET Oct 29

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