New study shows Pacific Decadal Oscillation and sea surface temperature drive US tornado strength

pdo warm and cold phasesFrom the University of Missouri-Columbia, one more example of how natural variation has trumped the supposed forcing of CO2 to make ‘bad weather’.

Pacific ocean temperature influences tornado activity in US, MU study finds

COLUMBIA, Mo. – Meteorologists often use information about warm and cold fronts to determine whether a tornado will occur in a particular area. Now, a University of Missouri researcher has found that the temperature of the Pacific Ocean could help scientists predict the type and location of tornado activity in the U.S.

Laurel McCoy, an atmospheric science graduate student at the MU School of Natural Resources, and Tony Lupo, professor and chair of atmospheric science in the College of Agriculture, Food and Natural Resources, surveyed 56,457 tornado-like events from 1950 to 2011. They found that when surface sea temperatures were warmer than average, the U.S. experienced 20.3 percent more tornadoes that were rated EF-2 to EF-5 on the Enhanced Fuijta (EF) scale. (The EF scale rates the strength of tornadoes based on the damage they cause. The scale has six category rankings from zero to five.)

McCoy and Lupo found that the tornadoes that occurred when surface sea temperatures were above average were usually located to the west and north of tornado alley, an area in the Midwestern part of the U.S. that experiences more tornadoes than any other area. McCoy also found that when sea surface temperatures were cooler, more tornadoes tracked from southern states, like Alabama, into Tennessee, Illinois and Indiana.

“Differences in sea temperatures influence the route of the jet stream as it passes over the Pacific and, eventually, to the United States,” McCoy said. “Tornado-producing storms usually are triggered by, and will follow, the jet stream. This helps explain why we found a rise in the number of tornadoes and a change in their location when sea temperatures fluctuated.”

In the study, McCoy and Lupo examined the relationship between tornadoes and a climate phenomenon called the Pacific Decadal Oscillation (PDO). PDO phases, which were discovered in the mid-1990s, are long-term temperature trends that can last up to 30 years. According to NASA scientists, the current PDO phase has just entered into a “cool” state.

“PDO cool phases are characterized by a cool wedge of lower than normal sea-surface ocean temperatures in the eastern Pacific and a warm horseshoe pattern of higher than normal sea-surface temperatures extending into the north, west and southern Pacific,” McCoy said. “In the warm phase, which lasted from 1977 to 1999, the west Pacific Ocean became cool and the wedge in the east was warm.”

In 2011, more than 550 deaths occurred as a result of tornadoes, resulting in more than $28 billion in property damage, according to the U.S. National Oceanic and Atmospheric Administration. McCoy says that with her findings, officials may be able to save lives in the future.

“Now that we know the effects of PDO cool and warm phases, weather forecasters have another tool to predict dangerous storms and inform the public of impending weather conditions,”

McCoy said.

The research will be presented at the National Weather Association Conference this fall.

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See video:

http://media.eurekalert.org/multimedia_prod/pub/media/63364_web.mp4

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Bill Taylor
October 17, 2013 4:10 pm

a study that is examining actual readings of actual events or DATA as opposed to a computer model…this will never meet peer review….lol

GlynnMhor
October 17, 2013 4:15 pm

Now we need only figure out what drives the PDO…

@njsnowfan
October 17, 2013 4:16 pm

Funny, I came across this older article on PDO and AMO and drought today from one of my followers.
It is a good article and is from 2004.
Seems their statements in 2004 are doing what they mentioned today with the PDO and AMO in their repot.
Take a look.
http://m.pnas.org/content/101/12/4136.full

October 17, 2013 4:18 pm

“Now that we know the effects of PDO cool and warm phases, weather forecasters have another tool to predict dangerous storms and inform the public of impending weather conditions,”
They think the long term trend driven by a 30 year cycle will have value in predicting imminent storms in specific locations in enough time to warn the public? Did I read that right?

@njsnowfan
October 17, 2013 4:26 pm

How can that be true on tornados, CO2 is the leading cause of more Extreme weather according to 97% of scientist.

milodonharlani
October 17, 2013 4:27 pm

I’ve read Warmunista comments disparaging the PDO as about fish & nothing else.
Any advance in real climatology since 1988 must be disparaged, since it all guts the Overlordship of the One True Gas.

Jquip
October 17, 2013 4:50 pm

davudmhoffer: “They think the long term trend driven by a 30 year cycle will have value in predicting imminent storms in specific locations in enough time to warn the public? Did I read that right?”
Notion would be that the risk threshholds in the model can be tinkered on the basis of the PDO temps to reduce error rates. Not sure that it’s at all feasible, but that’s the gist of it.

October 17, 2013 4:51 pm

davidmhoffer says:
October 17, 2013 at 4:18 pm
“Now that we know the effects of PDO cool and warm phases, weather forecasters have another tool to predict dangerous storms and inform the public of impending weather conditions,”
They think the long term trend driven by a 30 year cycle will have value in predicting imminent storms in specific locations in enough time to warn the public? Did I read that right?

Along with this:
“Now, a University of Missouri researcher has found that the temperature of the Pacific Ocean could help scientists predict the type and location of tornado activity in the U.S.”
I’m thinking they don’t mean the type and specific location of tornado activity.
This, along with information of warm and cold fronts.
Dunno.

October 17, 2013 4:56 pm

JohnWho;
I’m thinking they don’t mean the type and specific location of tornado activity.
>>>>>>>>>>>>>>
Well if they don’t know the specific location, how are they going to warn the public?
Forecaster: Breaking news! There’s going to be an F5 tornado sometime tomorrow somewhere in the United States. Evacuate now!

milodonharlani
October 17, 2013 4:59 pm

GlynnMhor says:
October 17, 2013 at 4:15 pm
This doesn’t conclude what drives the oscillation now, but suggests that closing circulation at the Isthmus of Panama had something to do with it setting it up:
http://geosphere.gsapubs.org/content/3/5/337.abstract
It appears that during the late Miocene & Pliocene Epochs, the equatorial Pacific experienced a more or less constant super El Niño state, with teleconnection effects in some regions corresponding to those observed now, only more weakly, during El Niños.
About three million years ago, North & South America yet again hooked up, blocking previously normal tropical oceanic circulation, possibly driving the Gulf Stream farther north, bringing moister air due to warmer waters, aiding the build up of ice sheets, modulated by the Milankovitch Cycle.
I think of monk seal distribution. Before the Isthmus formed, closely-related monk seal species evolved in Hawaii, the Caribbean & Mediterranean Seas. After the Paleo-Panama Strait became an isthmus the Hawaiian species was isolated. The Caribbean went extinct in the 20th century (not officially declared so until 2008), but the other two species are hanging on, but both considered critically endangered. They’re vestiges of a previous ocean circulation pattern.
Maybe the PDO connection is a stretch, but makes some sense, IMO.

October 17, 2013 5:00 pm

The evidence for this has been obvious for years, and I briefly discussed the PDO relationship with the location of tornados in the first chapter of m book. Nonetheless I am glad to see those conclusions verified in this study. http://www.amazon.com/Landscapes-Cycles-Environmentalists-Journey-Skepticism/dp/1490390189

October 17, 2013 5:01 pm

Forecaster: More breaking news! Al Gore called and said this one could be an F6. He’s working on having the scale officially expanded to accommodate the increased threat intensity. It could happen anywhere in the world, anytime in the next 11 centuries! That’s a millennia that goes to 11! We need to evacuate the planet!
There. Public warned.

October 17, 2013 5:09 pm

Jquip;
Notion would be that the risk threshholds in the model can be tinkered on the basis of the PDO temps to reduce error rates. Not sure that it’s at all feasible, but that’s the gist of it.
>>>>>>>>>>>>>
Since tornadoes are a local phenomenon driven 99+% by local conditions just hours before the actual event, it is not only not feasible, it is completely unreasonable to make such a claim.

Jquip
October 17, 2013 5:19 pm

davidmhoffer: “… it is completely unreasonable to make such a claim.”
Depends how often they update their forecasting model really. Ideally, that’s often enough to not matter. But then, while I’ve long thought HL Mencken was a naive optimist; best practices in Climatology have forced me to acknowledge I am also.

October 17, 2013 5:24 pm

Jquip;
Tornadoes are local weather events. Predicting trends in frequency and strength over a 30 year period is climatology. It is of zero practical use in predicting a specific tornado in a specific location.

Joseph Bastardi
October 17, 2013 5:25 pm

This is well known. Whats the big discovery. Also falling global temps are linked. I dont get the big revelation

October 17, 2013 5:29 pm

This article is not clear at all regarding statements that connect ocean temperatures and tornado activity.
For instance:
“They found that when surface sea temperatures were warmer than average, the U.S. experienced 20.3 percent more tornadoes that were rated EF-2 to EF-5 on the Enhanced Fuijta (EF) scale”
Maybe I’m not interpreting or reading it right.
Regardless. The correlation is there for more strong to violent tornadoes during global cooling years, which correlate nicely with the -PDO and more La Nina’s. When temperatures are colder at higher latitudes, the greater meridional(horizontal) temperature contrast provides increased energy to storms.
Note the higher incidence of strong to violent tornadoes during the global cooling years of the 50’s-60’s to the mid 70’s.
Global warming in the 80’s and 90’s was greater at the higher latitiudes of the Northern Hemisphere(along with melting Arctic ice). This decreased the meridional temp contrast, resulting in less energy and less violent tornadoes.
With our ability to detect tornadoes better the last few decades(doppler radar, spotters and expanding population), there has been a slight uptick in weak tornadoes reported from just this, that previously might have been missed.
http://www1.ncdc.noaa.gov/pub/data/cmb/images/tornado/clim/EF3-EF5.png

Chris4692
October 17, 2013 5:32 pm

See video:

No thanks, I’ll wait for the paper.

Editor
October 17, 2013 5:39 pm

The press release reads, ” They found that when surface sea temperatures were warmer than average, the U.S. experienced 20.3 percent more tornadoes that were rated EF-2 to EF-5 on the Enhanced Fuijta (EF) scale.”
My guess is that’s what will be reported. Let’s see how the mainstream media handles this.

October 17, 2013 5:40 pm

“PDO phases, which were discovered in the mid-1990s,..”
““In the warm phase, which lasted from 1977 to 1999…”
So the warm phase EXACTLY FITS the only global warming we’ve had due to people. I know correlation doesn’t (necessarily) imply causation but…since the theory of CO2 causing warming is based on the firm foundation of “What else could it be?”, which convinced 97% of climate scientists…well new work over the past couple of years has answered the CAGWers question with a firmer foundation. Note also, that the PDO wasn’t discovered until the mid 1990s (when global warming was nearly done). Oh well, with billions in research and a couple of trillion in mitigation and intimidation, I guess you win some and you lose some. On the bright side, we already have the legislators and activists in place to tackle global cooling.

Editor
October 17, 2013 5:41 pm

GlynnMhor says: “Now we need only figure out what drives the PDO…”
ENSO with sea level pressure in the North Pacific.

MinB
October 17, 2013 5:42 pm

I still find it hard to believe that the PDO was discovered only 15 years ago by someone studying salmon. IMO, this further weakens the credibility of climatologists who missed the climate impacts of just the LARGEST ocean on our planet. I’m not a scientist but this is fishy to me.

dp
October 17, 2013 6:01 pm

Bob Tisdale says:
October 17, 2013 at 5:41 pm
GlynnMhor says: “Now we need only figure out what drives the PDO…”
ENSO with sea level pressure in the North Pacific.

What drives ENSO and sea level pressure in the North Pacific?

TomRude
October 17, 2013 6:07 pm

Two different aerological domains… and concomittence is no causation.
This PDO, ENSO stuff circa Walker 1924 is the climatology of the 21st century after CAGW is failing. Statistical pressure centers… LOL Not surprising real driving processes are nowhere to be detected with this kind of approach.

Chris4692
October 17, 2013 6:32 pm

Bob Tisdale says:
October 17, 2013 at 5:41 pm
GlynnMhor says: “Now we need only figure out what drives the PDO…”
ENSO with sea level pressure in the North Pacific.

Go ahead, keep pushing. If I ever buy a reader it’s going to be so I can read that book of yours.