Modiki El Niños and Atlantic hurricane activity
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
Reader Comments
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So I guess lying to the public is not so bad after all...
Give me a break...have confidence in your abilities to do your job. That is why so many forecasters get bad reputations. Any good forecaster should be able to accurately predict the weather correctly for one given location 29 out of 30 days in a month. Yes there are times when the weather throws you for a loop and the unexpected occurs but in reality how often does that really happen? Not as often as you think.
How is it lying if you are right? TV forecasters make me sick. All they tend to do is leave their viewers confused. They just want to know will it rain or not. How hard is it to say yes we will see rain in so and so county today between 2-4PM? 90% chance? really? if you say 90 why not 100?
considering your handle, its hard to take you seriously LOL
Why because I have forecasted desert weather for quite a long time? When you have thunderstorms with cloud bases of six thousand feet, flat land and no friction, amazing outflows, that you have to forecast haboobs. Watching a haboob is one of the coolest weather features I have ever seen. It is amazing going from clear visibility to zero in under a minute. So yes make fun of my handle because I enjoy a classic Haboob event.
AOI
AOI
Not saying your wrong but unless you have a direct phone line to the almighty or Mother Nature I find it hard for a person to say that personally. If your right that is great news no activity is good to me.
yea people dont like being bold, I understand. They want to CYA themselves. But really if you look at the long wave pattern and they way it is setup, where is a real shot for something to form in the next few weeks? You need a sig change in the pattern for things to become favorable but when they do watch out because the storm will be a beast. Everything will be ripe.
you forecasted desert weather?
Wow thats hard lol, "Its going to be dry again for the 185th straight day. However tomorrow things will change, a cloud will appear in the sky and the city has decided to throw a parade in its honor." LOL
at 2 pm today it rained for 15 minutes, a mile down the street they didn't see a drop, our chance of rain today was 20%, you're an idiot if you're saying a good meteorologist could have told me we had a 100% chance of rain at my location at 2 pm a day, or even an hour before it happened.
Adrian,do you have the link to those graphics? What I have about TCHP is from May 19.
Haboob (sand storm) over Khartoum
With that comment, your lack of knowledge shows. Try forecasting a front moving through with snow on the mountains, high based thunderstorms producing outflows of over 50kts and vis dropping to zero. For aviation weather you have to be within 1/2 mile in vis, roughly 1 thousand feet in cloud bases and 5kts for wind within about a 15 minute window. try it someday. Write a TAF and tell me how easy you think it is. You dont see 60% in one of those.
HWRF
NOAA:Strong Outflow Winds and Blowing Dust Across the South Plains on June 22nd, 2006
Within a defined area yes. I didnt say the circle had to be 1 mile around but within a county, sure why not?
Those who know the least are the ones who pretend they know everything
video of a haboob
Image credit
95E has the potential that none of the other systems have so far this season
I dont know everything. I am probably the worst lake effect snow forecaster in the world. But that is not my area that I worry about. That is why I said for a given area.
so how do you forecast that? do you tell everyone living in that county you have a 100% chance of rain today even though 95% of the county won't see a drop or do you say you have a 0% chance of rain today even though 5% will see rain? Either way you're wrong and I won't be feeding a troll anymore.
Some seem to forget that the percentages show the fraction of the viewing area that will see rain, not necessarily the chance of rain
Easy, the definition of Isoladated storms is 1-2% coverage area. So if I was on tv or briefing the weather I would say today we will have brief isold afternoon showers and will have a limited impact on activities for today. So now people know it will rain somewhere, maybe not overhead because it is isold to the region and it will be shortlived so I dont need to worry about them.
Moving on, you rational basically means there is no reason for discussion about weather or for this site to exist
For the last time weather is NOT an exact science, matter of fact it is probably the most inexact science there is today.
Now I am moving on, I am sure you will comment again though
Just because one uses percentages does not make them a bad forecaster. Shoot this blog is full of outstanding weather forecasters. I am an all for nothing forecaster, been wrong before but my stats are actually quite good and I bet yours would be too if you forcasted for 30 straight days and went 100% on rain or no rain and you would shock yourself with how many times you would be right.
I think that is fair, there is so much shear out in prone regions and El Nino is sneaking in. There has been a lot of dust off of Africa as well. A lot of unfavorbale things lining up preventing formation.
Highly unlikely. I can only think of one season, sans 1907 and 1914, in which we had 2 hurricanes or less, and that is 1982. That El Nino event was much stronger than this one.
1998, 1999, 2000, and 2004 all started off very slow. In fact, 1999 did not have its second storm until August 19. This means nothing.
Again people getting carried away, I had no idea we were in August already lol
2?
Yep. Just made myself one of those blended ice drinks. Even the a/c is sweating....
Seems that if we don't start early every year, people start writing off the season early.
hey SG03 all the crazys are coming out and more yet to come
sit back enjoy the show
Blended ice drinks sounds good right about now.
My A/C does that too. I had to chizel out a block of ice from it the past.
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