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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I think GFS can answer this
As pat would say, nuthin'.
Wave approaching carib has the highest potential in terms of non-fish activity, but dry, dry, dry out there.
Visual that comes to mind is an old movie and a mummy coming to life coughing dust.
CFS at 22HR (July 17th) frontal area stalls like always in FL with trailing end in the GOM.. and by 26HR (July 19th) there's a low pressure area starting to develop in the SE GOM heading slowly NE.
Another one... @ 90HR (Aug 20th) on the ECFL coast.
Made me laugh but you never know... good night.
I don't really trust the GFS right now.
AOI
AOI
Yeah dude, tell me about it.
It has certainly gained a lot of notoriety this year due to its consistent forecasting of ghost storms.
It hasn't done terrible in the past but not too good this year.
Yeah, it's weird. Last year, it forecast the genesis of Bertha a week out.
This year, it develops major hurricanes in areas where there is no disturbance to take advantage of favorable conditions.
yeah, i think it is so slow that the models don't even know what to do...lol
I had July 10-12 the average day for this. If I am wrong than it is officially a slow season as we don't have a named stormed on the average days.
Plenty of active seasons have had the 1st storm form after July 10th
Correct, let me rephrase. A season that is slow to begin.
I like Orcas' blog, I think its informative
Also um in case you didnt know, most of this site is amateurs lol, good ones but they are amateurs lol
Link
More video's on the right menu
If you want to post private emails, not blog posts on the blog... have a ball :)
???
anyway im out, night everyone
It was a private email I sent to presslord.. apparently he wants to turn it into a blog war to have me banned from the blog...
gator...I didn't say I did...
ok i just think he expressed his opinion to you politely in the privacy of an email an you posted it.
I dont want to get into a online arguement with two people i respect. I just think we can settle this civily
Nope.. it was never posted on the blog.
It was an email, I don't have anything to hide.
Your email reply was sent to me in a email.. and you posted your reply on the blog.
Agreed :)
Anyone who wants to see the email.. just ask for it on WUmail... more then happy to forward it.
>_>
The season isn't slow; this is actually perfectly normal, and consistent with what one would expect in an average season.
That being said, in comparison to the active period since 1995, I suppose this season is a tad slow.
African Dust?
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