Modiki El Niños and Atlantic hurricane activity

By: Dr. Jeff Masters , 1:48 PM GMT on July 08, 2009

It's an El Niño year, which typically means that Atlantic hurricane activity will be reduced. But not all El Niño events are created equal when it comes to their impact on Atlantic hurricane activity. Over the past 150 years, hurricane damage has averaged $800 million/year in El Niño years and double that during La Niña years. The abnormal warming of the equatorial Eastern Pacific ocean waters in most El Niño events creates an atmospheric circulation pattern that brings strong upper-level winds over the Atlantic, creating high wind shear conditions unfavorable for hurricanes. Yet some El Niño years, like 2004, don't fit this pattern. Residents of Florida and the Gulf Coast will not soon forget the four major hurricanes that pounded them in 2004--Ivan, Frances, Jeanne, and Charley. Overall, the 15 named storms, 9 hurricanes, and 6 intense hurricanes of the hyperactive hurricane season of 2004 killed over 3000 people--mostly in Haiti, thanks to Hurricane Jeanne--and did $40 billion in damage.

A new paper published in Science last Friday attempts to explain why some El Niño years see high Atlantic hurricane activity. "Impact of Shifting Patterns of Pacific Ocean Warming on North Atlantic Tropical Cyclones", by Georgia Tech researchers Hye-Mi Kim, Peter Webster, and Judith Curry, theorizes that Atlantic hurricane activity is sensitive to exactly where in the Pacific Ocean El Niño warming occurs. If the warming occurs primarily in the Eastern Pacific, near the coast of South America, the resulting atmospheric circulation pattern creates very high wind shear over the tropical Atlantic, resulting in fewer hurricanes. This pattern, called the Eastern Pacific Warming (EPW) pattern, occurred most recently during the El Niño years of 1997, 1987, and 1982 (Figure 1). In contrast, more warming occurred in the Central Pacific during the El Niño years of 2004, 2002, 1994, and 1991. The scientists showed that these Central Pacific Warming (CPW) years had lower wind shear over the Atlantic, and thus featured higher hurricane activity than is typical for an El Niño year. One of the paper's authors, Professor Peter J. Webster, said the variant Central Pacific Warming (CPW) El Niño pattern was discovered in the 1980s by Japanese and Korean researchers, who dubbed it modiki El Niño. Modiki is the Japanese word for "similar, but different".


Figure 1. Difference of Sea Surface Temperature (SST) from average during the peak of hurricane season, August-September-October, for seven years that had El Niño events (except for 2009, when the SST anomaly for July 1 - 3 is plotted). On the left side are years when the El Niño warming primarily occurred in the Eastern Pacific (EPW years). On the right are years when the warming primarily occurred in the Central Pacific (CPW years). Shown on the top of each plot is the number of named storms (NS), hurricanes (H), and intense hurricanes (IH) that occurred in the Atlantic each year. Atlantic hurricane activity tends to be more prevalent in CPW years than EPW years. An average hurricane season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. Image credit: NOAA/ESRL.

What, then, can we expect the current developing El Niño event to do to 2009 hurricane activity? Kim et al. note that in recent decades, the incidence of modiki CPW El Niño years has been increasing, relative to EPW years. However, the preliminary pattern of SST anomalies in the Pacific observed so far in July (lower left image in Figure 1) shows an EPW pattern--more warming in the Eastern Pacific than the Central Pacific. If Kim et al.'s theory holds true, this EPW pattern should lead to an Atlantic hurricane season with activity lower than the average 10 named storms, 6 hurricanes, and 2 intense hurricanes. There is still a possibility that the observed warming pattern could shift to the Central Pacific during the peak portion of hurricane season, however. We are still in the early stages of this El Niño, and it is unclear how it will evolve.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

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Quoting hurricane23:


Compared to a few weeks back its pretty signifcant.Now we have to work on el nino.

Better view...


Doesnt look too bad...I was expecting the Caribbean and GOM to be higher in TCHP.
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Quoting hahaguy:
This is a picture that was sent into our local news station of bad storms down in Palm Beach County.


I just returned from a two day vacation in Palm beach. The Storm was incredible; there were numerous power outages due to lightning and high winds.
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That is a nice view Adrian. Looks hot in the Caribbean and Bahamas.
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Quoting BahaHurican:
Good maps, 23. The CAR and GOM may be warming up, but the record heat that fueled 2005 is nowhere is sight. That looks more like 10 May than 10 July of recent seasons.


Compared to a few weeks back its pretty signifcant.Now we have to work on el nino.

Better view...

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I am 100% sure we will see nothing in the Atlantic/Gulf until mid August.
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Good maps, 23. The CAR and GOM may be warming up, but the record heat that fueled 2005 is nowhere is sight. That looks more like 10 May than 10 July of recent seasons.
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A few maps....

SST'S of the florida coastline.



Carribean TCHP...


>


GOM TCHP...

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Quoting sebastianflorida:
Anyone else feeling a storm brewing near south american coast?


It certainly looks vigorous with abundance lower level convergence and upper level outflow. If it were to keep up like this, I might have to agree with your conclusion. However wind shear levels are high just west of it as a result of a result of a split ULL embedded in the TUTT, and it will thus be sheared up as it approaches tat region. This wave will have a better chance once it is near the SW Caribbean, as shear decreases due to the regression of the TUTT. According to the 18z NAM, the subequatorial ridge will also try to establish over the area, which is area the NAM is expecting potential cyclogenesis there. I doubt this will coalesce into a tropical cyclone, not only because shear is high, but also because of the steering patterns. The A/B high will remain potent according to the models, and will be ridging in much in the Western Caribbean. Therefore once this system reaches near the SW Caribbean, it will likely move into land, cutting off development.
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Quoting StSimonsIslandGAGuy:
Drak, for the last three years Bastardi has been saying the northeast is at heightend risk from major hurricanes--remember him talking about it at the beginning of the 2006 season on the O'Reilly Factor.

Bastardi give a lot of suggestion, remember when he forecast the develop of Debby a week before, he forecasted in 7 days to pass well north of the Leeward Islands and 7 days later to landfall in New York as a cat 2-3.
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Quoting KoritheMan:


I found a way to fix it, but it probably won't be until the weekend.



ment me in weather chat am wating for you we have lots too talk about
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Quoting sebastianflorida:
Anyone else feeling a storm brewing near south american coast?


That is not a storm.
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Anyone else feeling a storm brewing near south american coast?
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What are the conditions suppose to be like if that strong wave that is forecasted by the gfs emerges? As fas as shear, sst's and Sal? I know it is way too soon but track wise what are some thoughts? Are any other models starting to forecast such wave?
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Quoting Drakoen:


They are.
Also noting the pool of warm water off Equador, Columbia and S of Panama in the E PAC. We may not get that concentrated a pool of warm water on our side of the isthmus for another 4-7 weeks. No wonder the EPac is more active right now....
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Quoting Tazmanian:


did you evere get that yahoo IM fixs yet tell me yes you did


I found a way to fix it, but it probably won't be until the weekend.
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I think the mess down in extreme south islands will develop by tommorow night and eventually threaten someone.
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Member Since: December 31, 1969 Posts: Comments:
Looking Back At Hurricane Dennis.

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Quoting KoritheMan:
Interesting how Dennis rapidly intensified following its Cuban landfall, yet struggled so immensely to maintain that intensity in the final hours prior to landfall. Indeed, the storm had weakened considerably, much in the same way that Opal in 1995 did.

The NHC once noted that it has been a recurring theme with major hurricanes in the Gulf of Mexico. Specifically, they always tend to weaken a category or two prior to landfall. It's weird.


That's because most of the time they entrain Continental Dry Air when approaching the Gulf Coast.
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Quoting WeatherStudent:


Really? Who else?


LOL!
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Quoting KoritheMan:


xD, so true.



meet me in Weather Chat:
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Quoting KoritheMan:


xD, so true.


did you evere get that yahoo IM fixs yet tell me yes you did
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Evening all. It's good to see the SE CAR esp Trinidad get some rain. Hopefully the moisture will seep far enough north towards the Antigua area.

Really clear weather here today, due to high pressure, with some high clouds at times

Quoting Weather456:
One thing I hope for the future is Regional Weather Service for the Caribbean.
If not a true Regional service as in run by one body, then at least a closer collaboration between neighbouring countries' Met Offices. I know something of this nature already exists, but it doesn't seem as coordinated as it could be.

Quoting HadesGodWyvern:
kind of slow everywhere in the northern hemisphere

Pacific East - 4 cyclones
Atlantic - 1 cyclone
India - 3 cyclones (2 named)
Pacific West (JMA) - 4 cyclones, (JTWC) - 5 cyclones, (PAGASA) - 7 cyclones
Hmmm... I hadn't realized how low the numbers were. I was just thinking after u posted about Gorio that the WPac storms have been pretty mild so far.....

I'm chuckling at all the hype over the so-called late start to the season. The old Caribbean saying for July is "stand by", remember? Like a yellow caution light..... I'm also amused because the last couple of years all the historical statistics and record-recalling have been about "firsts" and "mosts". It's kinda refreshing to remember 1914, the year that does it all at the other end of the scale....

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Greetings!!!!!!!!!
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Quoting StSimonsIslandGAGuy:
Drak, for the last three years Bastardi has been saying the northeast is at heightend risk from major hurricanes--remember him talking about it at the beginning of the 2006 season on the O'Reilly Factor.

Thats why I call it Accuhype. Sometimes, I almost think that they try to "make" weather happen.
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Quoting KoritheMan:
Interesting how Dennis rapidly intensified following its Cuban landfall, yet struggled so immensely to maintain that intensity in the final hours prior to landfall. Indeed, the storm had weakened considerably, much in the same way that Opal in 1995 did.

The NHC once noted that it has been a recurring theme with major hurricanes in the Gulf of Mexico. Specifically, they always tend to weaken a category or two prior to landfall. It's weird.

The Gulf also has fairly shallow slope along most of the coastline, so there is generally less TCHP to pull from.

Also, I have finally updated my blog, feel free to check it out if you would like. (its educational, gives some things to look for along the Texas Coast, and is 100% fat-free!)
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Quoting Weather456:
The 12 ECMWF hinted a low in the E ATL. I do think a strong tropical wave will emerge next week but development uncertain


For now but we have to wait 5 days and it can change.
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Quoting WeatherStudent:


The guy's a legit idiot.


He's not the only one.
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Quoting WeatherStudent:


The guy's a legit idiot.


xD, so true.
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Quoting hurricaneman123:


thanks... looks like nhc has been having trouble updating pics


No the Invest was dropped at that point, so the floater is no longer updated
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Interesting how Dennis rapidly intensified following its Cuban landfall, yet struggled so immensely to maintain that intensity in the final hours prior to landfall. Indeed, the storm had weakened considerably, much in the same way that Opal in 1995 did.

The NHC once noted that it has been a recurring theme with major hurricanes in the Gulf of Mexico. Specifically, they always tend to weaken a category or two prior to landfall. It's weird.
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Quoting TheWeatherMan504:
4 years ago today...
Photobucket


yea dennis was a monster
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Quoting Weather456:


94L, look at the time stamp, July 6 2009, or Monday


thanks... looks like nhc has been having trouble updating pics
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Pencil that in, Joe Bastardi has 2 major hurricanes hitting New England by 2015.
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Quoting TheWeatherMan504:
4 years ago today...
Photobucket

Dennis!
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Quoting errantlythought:


Something seems wrong there, the ENSO says temps are above average across the gulf.


They are.
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Sea-Surface temperatures off the African coast line are only marginal for development. The computer forecast models show the retrogression of the TUTT in the EATL giving way to the light upper level easterlies associated with and upper level anticyclone over Africa. I suspect that dry air will be a probably. The GFS forms a monsoon gyre but when it's ready to pull out of the ITCZ is when it will have problems with cooler SSTs and a more stable airmass. For now i'm just forecasting for the depature of a strong tropical wave off the Africa coast. That will emerge on Sunday or Monday.
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4 years ago today...
Photobucket
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Quoting hurricane23:
I was not expecting this...Pretty dramatic change in heat content.AOML has not updated in weeks.



Something seems wrong there, the ENSO says temps are above average across the gulf.
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Quoting hurricaneman123:


what is that???probably extratropical


94L, look at the time stamp, July 6 2009, or Monday
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what is that???probably extratropical
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Penguin:
Incapable? Of course not. But just because storms in those years ulimately made landfall or were stumbled upon by a ship doesn't mean all were measured.

Go look at the full paper at the link I posted. He shows the obs for an average day in 1907, shows how the percent of TCs making landfall has dropped as remote sensing has improved and coastal populations have grown. And more. Really shows the effect of improved observations and the likelyhood that we missed many.

And, do you propose that it is impossible that a season like 2005 couldn't occur every 70 years or so? All of the factors that made that one what it was surely have happened before and will again...hopefully not anytime soon.
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather