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
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 — Blog Index
Where are the numbers on landfalls? Predict that.
If you use lets say 95-08 mean it amounts to a rather quite season number wise.
I was looking at the wind shear charts, some of the lowest values since the season began.
yup you cant predict that, but I will say this, if more storms are going to form closer to home, a good amount of storms may affect the US
Also it said ACE of 80, intense storms can still have low ACEs' if they form close to home
Great example is Charley, ACE was 10.6
I'm with ya there... more close to home stuff..
completely wrong message though
if you are only using 14 years then it is an incomplete data set. Predicted an average season, but the numbers dont matter at all, its where they form and hit.
Statement as of 3:47 PM EDT on July 07, 2009
... Record high temperature tied at Miami...
The high temperature today at Miami reached 95 degrees. This ties
the old record high temperature for this date... set back in 1992.
ok, so the sheer is lessening?
looked like the GOM and parts of the Carrib were under very low shear... first time to see that...lol! :)
I just think all the talk about a "slower season" compared to the last 14 years is sending the wrong message. Whether you like it or not, people will let their guard down
Correct.
11-day moving average shear (May-Present) confirmed this indicating that wind shear is slowing lessening. Shear is lessening faster across the GOM and SW N Atlantic/East and Central Atlantic but continues to decrease very slowly in the Caribbean and W Tropical Atlantic.
This also confirms the moving average
Link
Actually if you look back at some previous seasons with very low numbers most of those years have packed quite a 1-2 punch.1957,1992,and 1965 just to name a few.
And Isabel was another one. Charley skimmed us as a Cat 1 going up the east coast even though forecasters called for hurrricane conditions. Hurricane Irene (2005) tricked forecasters. They said it would either brush VA or make landfall in VA but instead it turned away.Scary moment though. Bertha I do believe in 1996 and fran (96) Also ivan went through Central VA.
quikscat keep showing rather strong winds in the blob off Honduras
ABNT20 KNHC 081733
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED JUL 8 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.
$$
FORECASTER KIMBERLAIN/AVILA
Still no development according to the NHC.
Wave axis is all but onshore now.
There is a wave along the s yucatan coast. Looks to have some rotation.
Actually , I think the NHC had the wave axis onshore this morning but after reviewing it shifted it back east, though I agree its probably basically on the coastline of Belize by now.
Oops sorry.
Hey steve!
Careful that dud year might have a 1-2 punch.Southern forida has a rather dark past during very slow seasons.
Well its only July 8th, I think some act like it mid-August already.
you're forgiven...
Rainfall patterns also show non fronal
Cyber Attack
This is reminiscent as to how Conflicker was to operate or is operating.
New york stock exchange site was hit earlier today.
Good...shut it down...it's just depressing, anyway...
Non-frontal but still baroclinic, not Barotropic.
21N87W ALONG 14N89W AND INTO THE E PACIFIC MOVING W NEAR 18 KT.
THIS WAVE COINCIDES WITH A SIGNIFICANT AREA OF INCREASED
PRECIPITABLE WATER ACROSS THE WRN CARIBBEAN AND CENTRAL AMERICA.
INTERACTING WITH A DIFFLUENT ATMOSPHERE ALOFT...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FOUND ACROSS THE WRN
CARIBBEAN AND PORTIONS CENTRAL AMERICA FROM 14N-19N BETWEEN
82W-90W.
CARIBBEAN SEA...
A TROPICAL WAVE IS TRACKING WWD ACROSS THE ERN YUCATAN PENINSULA
AND CENTRAL AMERICA CONTINUING TO IMPACT THE NW CARIBBEAN WATERS
AND PORTIONS OF CENTRAL AMERICA. THE WAVE CONTINUES TO MOVE
BENEATH AN UPPER LEVEL ANTICYCLONE CENTERED OVER WRN GUATEMALA
NEAR 15N92W AND THE INTERACTION BETWEEN THESE TWO FEATURES IS
GENERATING SCATTERED SHOWERS AND TSTMS FROM 14N-19N BETWEEN
82W-90W...INCLUDING PORTIONS OF HONDURAS...BELIZE AND GUATEMALA.
ALSO SCATTERED SHOWERS AND TSTMS ARE ACROSS THE SW CARIBBEAN AND
FAR ERN COASTAL AREAS OF WRN PANAMA...COSTA RICA AND SE
NICARAGUA FROM 8N-13N W OF 80W. SURFACE CONVERGENCE DUE TO THE
PROXIMITY OF THE E PACIFIC ITCZ ALONG 8N IS ENHANCING THIS
ACTIVITY. THE REMAINDER OF THE CARIBBEAN...WITH THE EXCEPTION OF
THE FAR NERN WATERS...IS UNDER THE INFLUENCE OF A SAHARAN AIR
LAYER OF DUST SUSPENDED IN THE MIDDLE LEVELS OF THE ATMOSPHERE.
THE SUSPENDED DUST IS OBSERVED ON VISIBLE SATELLITE IMAGERY AND
NUMEROUS OF THE UPPER AIR TIME SECTION ANALYSES ACROSS THE ERN
AND CENTRAL CARIBBEAN. WITH THIS DRIER AIR IN PLACE...ONLY A FEW
ISOLATED LOW-LEVEL SHOWERS ARE NOTED N OF 16N E OF 67W IN
ASSOCIATION WITH A SURFACE TROUGH THAT EXTENDS FROM THE CENTRAL
ATLC TO NEAR MONTSERRAT. FRESH TO STRONG ELY TRADE WIND FLOW
CONTINUES ACROSS THE BASIN AND IS FORECAST TO PERSIST THROUGH
FRIDAY AND INTO THE WEEKEND.
From the 205 NHC discussion.
of course, the rebuttal comes before the report is officially published...but, OF COURSE, the surface temperature record is *accurate*
Its one of my AOI's :)
Good lord, he's back...
Viewing: 101 - 151
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 — Blog Index