As we end September, tropics look to remain peaceful

I am on the road in Florida shooting interviews for our upcoming documentary due out in March. However, it is still hurricane season so let’s take a look at what’s going on across the tropics today.

Nadine is still on the maps as a moderate tropical storm. The forecast keeps Nadine around for the next five days as it moves over warmer sea surface temps. However, increasing shear should eventually take over and hopefully weaken the storm enough to dissipate it. We shall see, Nadine has been around for a while now.

Elsewhere in the Atlantic, all is quiet with no areas of development expected nor seen in the various global model forecasts. While October can be a busy month, I do not see much to suggest that we will see any significant development over the next week to 10 days. Once we get in to mid-October, that could change but we’re talking almost three weeks away.

In the eastern Pacific, Miriam is weakening and is no longer forecast to impact the Baja peninsula as the low level center will fade westward as the mid and upper level energy gets sheared off and heads in to Mexico, bringing some rain but that’s about it.

I’ll post more tomorrow as I continue to travel around Florida.

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Nadine back on the maps as we watch Miriam in the east Pacific

TS Nadine Over SSTs Just Warm Enough

TS Nadine Over SSTs Just Warm Enough

If you were sick of hearing about Nadine, well, you might want to cover your eyes for the next week or so because it’s back as a tropical storm again. Since Nadine was not swept up in to the north Atlantic in recent days, it has been allowed to meander in the eastern Atlantic and as high pressure builds to its north, the storm will be moving back westward. This will place Nadine over water temps that are just warm enough to allow for it to re-develop and that is already taking place. Top winds are estimated to be near 60 mph with a pressure of 986 mb. By later in the coming week, the storm is forecast to become a hurricane again and this will continue to add points to the ACE index, which now stands around 90. This index measures the amount energy expended by Atlantic tropical cyclones. Nadine will add several more points over the coming days, like a basketball team blowing out its opponent but they keep running up the score.

Elsewhere in the Atlantic Basin, all is quiet with no areas of organized convection seen in satellite imagery. None of the global models develop anything over the next week or more either. I do not think we’ll have much to be concerned with until we get to about mid-October when there is a secondary peak to the hurricane season coming up. More on that later.

TS Miriam Track Map in the East Pacific

TS Miriam Track Map in the East Pacific

In the east Pacific, tropical storm Miriam continues to strengthen well to the southwest of the Mexican coastline. It is forecast to become a hurricane and it could eventually turn back towards the Baja peninsula as the steering pattern begins to change over the northeast Pacific. How soon this turn happens and how strong Miriam will be at that point is difficult to tell right now. Interests along the Baja should keep up with Miriam’s progress.

Quick note to remind our iPhone app owners to update the app to the most current version. We have added 5 tracking maps of our very own plus a new home screen and manual refresh buttons on our social media feeds. These are vast improvements over the original version which debuted on August 1. So go to the App Store on your device and get the update. If you don’t already have HurricaneTrack, get it now and enjoy a daily video blog plus our new maps and plenty of landfall features when we are active in the field.

I’ll have more here tomorrow.

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September likely to end quiet, but what about October?

With the exception of TS Nadine, which is gradually losing its tropical characteristics, and 94L, itself a sub-tropical type storm system, the Atlantic Basin is very quiet. There are no additional organized areas of deep convection noted and none of the global computer models develop anything over the next several days.

In the east Pacific, invest area 93-E shows signs of becoming the next tropical depression but it will move away from Mexico. Thus we will likely end September without a hurricane threat to the U.S. or Mexico. Leslie did bring near hurricane force winds to Newfoundland earlier in the month but that’s it, we have escaped the peak month without a serious landfall event. Remarkable considering all of the activity that we have seen but since it has all been out of the deep tropics and over the open ocean, the result has been no issues to speak of for land.

The Western Caribbean is favored during the month of October

The Western Caribbean is favored during the month of October

How about October? What can we expect as we enter the last significant month of the hurricane season? Well, climatology suggests that a lot can happen. The patterns shift back to the western Atlantic and especially the western Caribbean Sea in terms of development potential. Sea surface temps in the region are at their peak with plenty of deep ocean heat content available. We’ve seen some incredible October hurricanes with the most notable in recent times being Wilma seven years ago. It developed towards the end of the month and was at one time the most intense Atlantic hurricane ever recorded with a central pressure of at least 882 millibars and a 2 mile wide eye. Wilma went on to menace the Yucatan before making landfall in SW Florida on the 24th of October. That was the last time any hurricane has made landfall in Florida, much less a major hurricane.

Will this October have something to track in the western Caribbean? Obviously I do not know for sure but there are couple of things to look for which might help to uncover a few clues.

First, as I mentioned, climatology suggests that we should see at least one hurricane develop in the western Caribbean or vicinity during October. This region is favored with plenty of development taking place over the past 100 years. In other words, we would normally look to the western Caribbean and/or Gulf of Mexico in October for the highest potential for development.

ECMWF MJO forecast not yet showing a favorable period for the western Caribbean

ECMWF MJO forecast not yet showing a favorable period for the western Caribbean

Second, the MJO or Madden-Julian Oscillation. The best way to describe this phenomenon is to think of it as a period of time when upward motion in the tropics is favored, thus allowing for deep convection to develop and sustain. The MJO typically moves around the globe once every 30 to 40 days and helps to kickstart tropical convection. Sometimes it is quite weak and hardly noticeable. Other times, it is very prevalent and leads to a burst of several tropical cyclones over a two week period or more. Right now, the MJO favors western Pacific development and none of the dynamic models indicate that it will move in to the western Caribbean anytime soon. However, once we get past the end of the month, I suspect that we’ll see some changes and as we approach mid-October, I would not be surprised at all to see a chance of something developing. If we get a favorable MJO pulse, those odds will go up considerably.

Finally I think that the lack of a significant El Nino event will also help to increase the chances of an October hurricane in the western Caribbean. El Nino usually means stronger than normal winds cutting across the Caribbean due to an increase in upward motion over the tropical Pacific. So far, the warming in the Pacific has been weak at best and we are not officially in an El Nino yet. This may be just enough to allow for one or two more hurricanes to develop before the season ends on November 30.

For now, the tropics are of no concern and won’t be for the next few days and probably longer. Once we get in to October, we’ll have to watch the climatologically favored areas for the possibility of something coming along to track. Let’s see how these other indicators help with monitoring conditions that may lead to such development. In the meantime, have a great weekend and enjoy the Fall weather. I’ll have more here on Monday.

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Subtropics rule the season

Hurricane Chris set the tone for the remainder of the Atlantic hurricane season

Hurricane Chris set the tone for the remainder of the Atlantic hurricane season

It has been a rather odd hurricane season so far. I say this because most of the activity, the stronger activity anyway, has developed well outside of the usual breeding grounds of the deep tropics.

Hurricane Chris, which formed back in the latter half of June, did so at 41.1 N latitude! That is incredible for so far north so early in the season.

Next up was hurricane Ernesto, the only hurricane to form south of 20 N latitude this season out of eight total hurricanes so far. However, Ernesto struggled to become a hurricane until right before landfall, another common trait this season as we’ll see with Isaac.

Gordon became the season’s third hurricane and again, well outside of the deep tropics, attaining hurricane status at 34.0 N latitude while heading for the Azores Islands.

Then there was Isaac. Several times during Isaac’s life span it looked as though it could become a powerful hurricane. Instead, Isaac struggled with dry air and the lack of an inner core all the way in to the north-central Gulf of Mexico. One private weather firm loudly proclaimed that Isaac could be another Katrina or worse! And yet the fourth hurricane of the season only managed to reach 80 miles per hour before making landfall in Louisiana. While Isaac was a large hurricane and caused significant flooding from surge and fresh water flooding, it was not a very convectively active hurricane with a well defined inner core. This kept the winds at flight level that were being measured by recon from reaching the surface. Fortunately for residents of the central Gulf Coast, Isaac was only a fraction of the intensity that we all know it could have been had environmental conditions been more favorable.

It took all the way until hurricane Kirk on August 30 to finally get a category two hurricane. And of course, this happened while Kirk was well out of the deep tropics, affecting only shipping interests.

Leslie also had promise to become a large and intense Atlantic hurricane but it too fell far short of that potential and spared Bermuda with only passing tropical storm conditions. Stronger winds and more pronounced effects were felt in Newfoundland but even here conditions were not as bad as what could have been experienced had Leslie been a much stronger hurricane.

Michael is the season’s only category three hurricane so far and guess what? It made it to this intensity at 29.6 N latitude while out over the open central Atlantic over water temps of about 80 to 81 degrees. That’s it. Just enough to get the small hurricane to really ramp up – and it maintained a strong eye feature for several days. Luckily, Michael was far from land and only padded the ACE index score for the season.

We are still tracking Nadine which has been on the map since the 11th of this month. Nadine became the season’s eighth hurricane on the 14th at 30 N latitude. This is remarkable and a sign that something is definitely “wrong” in the deep tropics this year.

I have heard everything from El Nino to mid-level dry air being responsible for the lack of intense cyclones in the deep tropics. I am sure researchers such as Dr. Philip Klotzbach at Colorado State University will be looking in to the source of this unusual pattern and I look forward to learning more about it myself at next year’s National Hurricane Conference in New Orleans. The obvious benefit here has been a substantial reduction in damage resulting from less intense hurricanes impacting land. What if Ernesto had become a 140 mph cat-4 at landfall along the Yucatan? What if Isaac had become another Katrina and brought 30 feet of surge instead of 12? We know the answers….it would have been horrible. Been there, done that. I am sure no one is complaining about the feeble nature to this season’s hurricanes. I hope too that people are curious as to why? Why would conditions be so hostile in the deep tropics? What was the root cause if it can be pin-pointed down to something that simple? Will this pattern continue for the next several seasons? While we can be thankful for the lack-luster performance of this year’s hurricanes thus far, I think understanding the mechanics of such good fortune (it’s relative, I know, as plenty of people are still cleaning up after Isaac) is important in case we see the reverse take place next season or next month for that matter.

In any case, it all boils down to this: the tropics have been strange this season and strange has meant fairly benign events for us to deal with. So far, it looks to stay that way for the next week at least. Although, once again, we will be looking for possible storm development out in the open central Atlantic, well north of the deep tropics which seem to be closed for repairs….

I’ll have more tomorrow.

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Tropics nice and quiet except for pesky Nadine

The Atlantic, Caribbean and Gulf are Mostly Quiet with the Exception of TS Nadine Near the Azores

The Atlantic, Caribbean and Gulf are Mostly Quiet with the Exception of TS Nadine Near the Azores

The Atlantic Basin is unusually quiet for this time of the hurricane season and I do not see that changing anytime soon.

We are tracking TS Nadine out near the Azores but that’s it and even Nadine is not that much of an issue.

Some people are blaming El Nino for the quietness, I do not think that the tropical Pacific is really all that warm compared to normal and we are certainly not in an official El Nino period as of yet. In fact, the central Pacific SST anomalies cooled by .30 degrees C in the recent week – and this is also not typical of an El Nino. So what is the reason behind the quiet time? It’s most likely the MJO phase which is currently not favorable in the Atlantic Basin. In other words, we are not in a pattern that supports upward motion in the tropics across the Atlantic, Caribbean or Gulf of Mexico. The lack of instability and generally unfavorable conditions are simply not allowing for any new development.

Looking at the long range models, I do not see any signs of change over the next week to 10 days either. We may escape September with no additional named storms in the Atlantic.

As for October? We’ll wait and see. Without a solid El Nino in place, it is possible that we could have a normal October with a couple of hurricanes developing somewhere – but that’s the key, where? Time will tell. For now, the tropics are of little concern and look to stay that way for quite some time.

Be sure to catch today’s video blog in our iPhone app as it covers these topics graphically. Also, we are anticipating a new update to the app within the next few days that I will address in tomorrow’s blog post.

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