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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When I was working on Project Runway we did an episode at the Today Show. Poor Al was limping out to his car after the show. He has really gained wieght since his bariatric surgery. I thought it was sad.
Stephanie Abrams...now that's another story.
The woman screeches and doesn't use proper English. Don't know how she got where she is.
Poor Al. I just don't watch either NBC or the weather channel anymore.
Yea it was really sad. You could tell his knees were going bad from the wieght
...
AS THE TROPICAL WAVE ALONG 52W TRACKS CLOSER TO THE LESSER ANTILLES...INCREASED MOISTURE AND
INSTABILITY IS NOTED ON SATELLITE IMAGERY AS SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THE WINDWARD ISLANDS S OF 14N E OF 63W. FRESH TO STRONG ELY TRADE WIND FLOW CONTINUES ACROSS THE BASIN AND IS FORECAST TO PERSIST THROUGH THE WEEKEND.
Link
*blinks*
*looks at the calendar*
*blinks again*
Um... lets finish out the 2009 season first.
No doubt! I think you just pulled another thought from my head... ouch this is getting painful :)
I just extended my own GFS run. Looks like it is spinning up 2 storms in the MDR at 9720 hours. One of them could be a threat to PR on August 26, 2010. Landfall at about 3 PM.
LMBO!!! did it spin up any storms in December?
Are you making that up or is that true?
Yep.....i won't take much for something to spin up there....
just having a little fun...
I definitely agree there. Waters are toasty, and when I glanced at the wind shear maps, it was marginal (but trending towards higher shear). That said... who knows what could happen.
Nothing yet. As TS alluded to, stalled fronts in the GOM have a tendency to spin up if they stay stalled out long enough and other conditions are right. This time of year, the biggest question mark will be shear.
Which one!
With a nino officially established i dont see anything developing till mid/early august.Strong westerlies all across the area.
What king of impact will this nino event will have on this season is yet to be seen.
I knew someone would have already posted that.
Interesting run. Any model support?
of blanca, giving it more hot water and more time
before it hits dry air.
The 1016 mb line is forecast to be almost to Trinidad in a couple of weeks, which is quite high; BUT it is where the 1016 line sets up once early August comes that is more important.Surface pressures are quite high in many areas across the basin with a cool pocket of sst's across the main development region.
None that I've seen, not even ensemble members.
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