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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Is there a relationship of like storms forming in the Atlantic after the E'Pac?
One week.Be prepared.
the atl the caribbean and the gomex are vey trnquil this morning, what i have noticed the ingredients for the start of the season is about coming together. the stable atmosphere through out the MDR is allowing ssts to increase , while shear is becoming favourable. the SAL is also decreasing and the stage appears set for the cape vere season. hope this lull is not a precursor of things to come
6Z GFS is more east and north and less aggressive...
"LONG TERM...(SUN-THU)...WITH QUITE A FEW RECENT DISCREPANCIES
BETWEEN THE GFS AND ECMWF...DECIDED TO WAIT FOR THE NEW 00 UTC EURO
RUN TO ARRIVE...AND THEN DECIDED TO WEIGHT THE EXTENDED PACKAGE
TOWARDS THE NEW ECMWF SOLUTION WHICH DIFFERS SLIGHTLY FROM THE GFS.
THEREFORE...WENT WITH WARMER AND DRIER CONDITIONS FOR SUN THRU TUE
AS THE UPPER RIDGE TO THE W TRIES TO BUILD BACK EASTWARD TOWARDS THE
SE U.S....WITH COOLER AND WETTER WEATHER RETURNING FOR WED AND THU
AS THE RIDGE RETROGRADES ONCE AGAIN...WITH YET ANOTHER UPPER LEVEL
TROF PROGGED TO SET UP OVER THE EASTERN SEABOARD."..........
Another trough.
It is a beautiful morning here at 11n 61w. No dust, after a week of heavy. Not a cloud to be seen. Excellent visibility. Feels like January to me !!
I see a patch of cloud on the Sat Images, off to the East. Have to hope for some rains from that.
Is it still dryseason? In July??
something is gonna be there next week by Sunday or so
Kinda cool and still overcast here but with no rain despite the clouds continually trying to.
As long as it doesn't rain in Cardiff today...
The Ashes!
Yuck! I like the 6z run that our Ike showed. :)
Ummm. By "our" I mean the blogs Ike and not the storm that hit here. And good morning everyone. Sry just woke up and that post caught my eye. Ugh. :( maybe I should go back to bed til October.
that model is way out there 384 hours out is throwing darts at a board, but I think the GFS is just beginning to adjust that we are heading into Cape Verde season.
I know about it being so far out. Lol. It would be nice if people or places had that much warning. Then again it might just make us more nuts than a 2 day warning. Lol.
TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W TO THE SOUTH OF 17N MOVING WESTWARD 15 TO 20 KT. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG ITCZ PRECIPITATION FROM 8N TO 12N BETWEEN 49W AND 58W.
Link
Shear Map
You like it?
can you post the link please?
Guess I'd better go ahead and take the dog for a long walk now...
Link
Well wonderkid, I live on the Gulf Coast and if by some fluke this does happen I hope it goes right up your snout first. Sorry for sounding trollish folks but I find post like that bothersome.
You like getting hurricanes, and seeing people lose a majority of their belongings and possibly their lives? Are you actually serious?
I think he wants the hurricane to hit him...he probably thinks their fun.
Looks to be improving starting tomorrow,decent weekend, we're dancing in the streets,if temps hit 80 these days.
I agree with you there. Hurricanes aren't something to wish for. If you think they are fun, I have quite a few examples of how they aren't fun, including a few on my blog. Hurricanes suck. Pretty to look at, horrible to live through.
LOL,you sent me into a deep depression,thanks.
We have that same ritual in the south. Only we call it the "Yeah the cold front didn't stall dance" Lol
I've had an interest in tropical systems for over 30 years and been through quite a few storms. I don't want anybody affected by these monsters because the days following a storm are simply miserable, to say the least.
Just as we're paying for living in the south right now. And it stinks when we don't get any cool down. I remember in '06 going fishing on my dads birthday on January 5th. But then again we got snow last December. Lol. That was a rare treat.
No foul wonderkid, just be careful how you word your posts. We know you don't wish these storms on anyone......as I would never really wish one on you. Keep on blogging!
Some will say GFS did well last year, but GFS, honestly, is rather poor at cyclogenesis and always has been. Good for track forecasts of an existing TS or better without large intensity changes. You guys are driving framing nails with a screwdriver.
I hear ya about the A/C. Didn't 2 hit you one after another in '04? If I got the wrong place I appologize. I saw a story about I think Francis and Jean hitting in the same place. It was an interview with the electrical workers where that happened. They were like " Come on! We just got it back up." I can't imagine taking a hit so soon after another like that.
Good Day to you Ladies and Gentlemen.
If you are looking in the coast of Africa 4 to 6 days from now, they develop the CV wave.
I'am not really agree with you. If they are, so the others are as well. The GFS is the main model in the U.S.
Link
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