Common link in extreme weather events found – and no, it isn't AGW

From the University of Wisconsin-Madison  something you’ll never see posted on Climate Progress or mentioned by weepy Bill McKibben because it mellows their harshness.

Global winds could explain record rains, tornadoes

MADISON –Two talks at a scientific conference this week will propose a common root for an enormous deluge in western Tennessee in May 2010, and a historic outbreak of tornadoes centered on Alabama in April 2011.

Both events seem to be linked to a relatively rare coupling between the polar and the subtropical jet streams, says Jonathan Martin, a University of Wisconsin-Madison professor of atmospheric and oceanic sciences.

But the fascinating part is that the change originates in the western Pacific, about 9,000 miles away from the intense storms in the U.S. midsection, Martin says.

The mechanism that causes the storms originates during spring or fall when organized complexes of tropical thunderstorms over Indonesia push the subtropical jet stream north, causing it to merge with the polar jet stream.

The subtropical jet stream is a high-altitude band of wind that is normally located around 30 degrees north latitude. The polar jet stream is normally hundreds of miles to the north.

Martin calls the resulting band of wind a “superjet.”

Jet streams in the northern hemisphere blow from the west at roughly 140 miles per hour, and are surrounded by a circular whirlwind that looks something like a tornado pushed on its side. The circulating wind at the bottom of the jet stream blows from the south. On the north side, the circulating winds turn vertical, lifting and cooling the air until the water vapor condenses and feeds precipitation.

A superjet and its circulating winds carry roughly twice as much energy as a typical jet stream, Martin says. “When these usually separate jet streams sit atop one another, there tends to be a very strong vertical circulation, which produces clouds, precipitation and tornadoes under the right conditions.”

And because the circulating wind in a superjet moving across the U.S. south picks up moisture from the Gulf of Mexico, “the superjet gives a double-whammy – more moisture, and more lifting, producing that intense rain.”

That was the case in May 2010, when 10 to 20 inches of rain fell around Nashville.

Andrew Winters, who is now a graduate student studying with Martin, latched onto the Tennessee flood as the topic of his senior undergraduate thesis in 2010. “It had a lot of interesting aspects, brought an anomalous amount of moisture into the southeast, and that hefty amount of rain,” Winters says.

And that super-strong jet stream “could be traced back to conditions in the western Pacific, almost a week earlier,” Winters says.

Martin and Winters describe their work in talks Dec. 6 and 7 at the annual meeting of the American Geophysical Union in San Francisco.

Studies of the Tennessee floods, the Alabama tornados, and an odd October storm in Wisconsin showed “that when the subtropical jet is pushed poleward under the influence of strong thunderstorms in the western Pacific, it seems to result in these intense storms in the U.S. midsection,” Martin says. “It’s a really fascinating global connection that occurs seven to 10 days later.”

Martin also suggests the altered position of the subtropical jet stream may be linked to global warming.

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says.

That idea can be tested, Martin adds.

“Historic weather data should tell us whether there has been a change in the frequency of these overlapping events, and whether that might be linked to a change in high impact-weather events. It’s an interesting lead that could help us understand one possible mechanism by which a warmer climate could lead to an increase in severe weather,” he says.

Although hurricanes can be tracked for a week or more as they cross the Atlantic Ocean, weather phenomena seldom last so long, Martin says. “If the subtropical jet stream is rearranged and superposed on top of the polar jet stream, it might be the mechanism that allows for this very long delay, a disturbance that can have discernible effect on severe weather thousands of miles downstream, and a week or more later.”

Martin says that if the new analysis survives further study, it could contribute to severe weather forecasting. Though severe weather was forecast a day or two in advance of the deadly tornado outbreak in the Southeast this April, “most tornado forecasts are made 12 or at most 24 hours in advance. That saves lives. But if we get the idea five or six days in advance that we should watch the position of the jet streams, we could say, ‘Hey, we have a pretty exciting week coming up, we have to be on high alert.'”

###
5 1 vote
Article Rating
51 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
December 5, 2011 7:25 pm

For those interested, the following link is to various weather maps including North American jet stream maps. I use them for my own forecasting for the Pac NW/ SW BC.

December 5, 2011 7:26 pm

Darn, I forgot to say thanks for a great article…
Thanks for a great article!

December 5, 2011 7:27 pm

I can’t believe I forgot the link… Must sleep…
http://www.weatherimages.org/data/imag192.html

StuartMcL
December 5, 2011 7:29 pm

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says.
No sh*t Sherlock! Why am I not surprised?

JustMEinT Musings
December 5, 2011 7:32 pm

ahhhhh —– A New Jet Stream Alert, a bit like Solar Watch etc could be very beneficial to human kind….. and how fortuitous that it is not cause by AGW…… but wait (I hear the skeptic in me saying) for sure they will find some way of accusing this anomoly on human cause, can’t allow facts to get in the way of screwing us (taxation) for climate change.

David Falkner
December 5, 2011 7:37 pm

Hang on a tick, let me shake the old 8-ball………
Ah, yes, “Weather, not climate.”

John-X
December 5, 2011 7:40 pm

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says.
Ugh.
A few years ago I saw a documentary called “Loving Lenin,” about how the cult of lenin went on and on, long after soviet communism was dead.
There was a once-prosperous guy who lived near the university who, for a small fee would help you write your paper (most college towns in the world have several of these types). But in the soviet union, these guys had to have a special talent.
No matter the subject of your paper, it HAD to include the marxist-leninist perspective. Your interest was probably in the subject, not what the communist deities might hypothetically have pronouned about it. So, these guys, who had mastered the slogans and jargon and could insert this political jibberish on any subject anybody wrote about, were extremely valuable to the academic interested in his chosen subject, and in staying out of serious trouble.
We in the formerly free world have now raised an entire generation of academics who have to have mastered this same sort of “skill”: write a paper about weather, climate, anything remotely related, and you have to throw in phrases like, “in a warmer climate,” “as a result of increased man-made greenhouse gases,” or similar nonsense, in order to avoid seeing yourself denounced in the pages of Pravda (unspecified unpleasant consequences to follow).

December 5, 2011 7:41 pm

Another point is that it’s the temperature differential of these jet streams and the vortices that are created as a result are the causes of these extreme weather phenomenon.
In a warming Earth, the temperature differential between equatorial and polar regions would be lessened, which would tend to LOWER the incidence of extreme weather.
That seems to fly in the face of CAGW blogma, which proposes a warmer Earth creates a greater propensity for extreme weather events.
Am I missing something?

Dave
December 5, 2011 7:42 pm

Martin also suggests the altered position of the subtropical jet stream may be linked to global warming.
There the grant money will cont.. to flow.
So how do they explain little or no warming since 1998 and the ocean cooling trend?

Jean Parisot
December 5, 2011 7:47 pm

I also see a common link to powerful far off sources of funding and power … how does a” warmer climate” produce more organized storm in Indonesia?, are the historic tropical storm and temperature records good enough to trace this phenomenon? how do we test it- tracer gas transfer from one stream to another to indicate a substantial interaction and subsequent change in flow conditions?

Bill H
December 5, 2011 7:49 pm

Interesting premise..
i would look to the polar jet for your answer. warming and cooling will affect the polar jet first. great differentiation in temps will cause the polar jet to widen or withdraw.
as you can see from the last ten years the polar jet has grown forcing the subtropical jet to the equator. the difference is cooling in the arctic. this changed the temperature pressure differential. the atmosphere of the arctic makes it primary for cooling depending on many factors.
During the previous ten years it was warming so the differential was primarily equatorial. the warming in the poles caused the polar jet to retreat… which allows for formation of bigger storms and cyclones.
one of the biggest fallacies i can see about the AGW lie is how they ignore major factors…

Interstellar Bill
December 5, 2011 7:51 pm

More likely it’s linked to the impending Grand Minimum.
Recent weather extremes have the flavor of the early 1300’s
when the Little Ice Age first hit.
Every time in the past the Earth got warm, weather was less extreme, not more.

davidmhoffer
December 5, 2011 8:10 pm

Both events seem to be linked to a relatively rare coupling between the polar and the subtropical jet streams, says Jonathan Martin>>>
WHAT? The polar and subtropical jet streams are COUPLING?
That’s disgusting! In public no less! They’re not even married! No wonder they spawn illigitimate children like tornadoes and freak storms. No discipline for their progeny either, just let them run amock, willy nilly, making a mess everywhere and not taking responsibility for it. Bad parenting I tell you! Then look at what else is going on:
A superjet and its circulating winds carry roughly twice as much energy as a typical jet stream, Martin says. “When these usually separate jet streams sit atop one another, there tends to be a very strong vertical circulation>>>
Well, we’re into too much information land as it is, but how much energy in what position, really, is that fit for a family oriented blog?
Well, put that aside, let’s focus on the fact that the winds carry TWICE AS MUCH ENERGY and result in a VERY STRONG VERTICAL CIRCULATION… in other words….
COOLING!
So, following Martin’s logic, and just ignoring his token “must be global warming” statement, seems to me that the freak weather he’s describing is a sign of large amounts of energy being belched into the upper atmosphere from whence the silly photons can zip off into space with nary a worry about bumping into a hungry CO2 molecule that might just swallow them whole.
Gasp! Did Trenberth take these things into account? Maybe the missing heat didn’t go down, it went…up? You know, sorta like SPENCER MEASURED?
I want my PhD, and I want it now.
I’ll even take a used one, doesn’t have to be new. Just scratch Trenberth’s name out on his, write mine in. Good enough for me, and he doesn’t need his anymore. If he asks… just say it is missing, and it is a travesty that it is missing.

December 5, 2011 8:12 pm

If the polar area is warming faster than the subtropical area and this applied to the jet streams then the temperature difference would be less therefore the strength of the winds would be less therefore less not more storms of this nature with warming.?????

December 5, 2011 8:16 pm

Bravo to Winters for looking at Anything Besides Carbon as a cause of weather!
The sunspot minimum mentioned by Interstellar Bill looks like a pretty good correlation. If you examine the long Armagh record along with sunspots, you’ll see the storminess was very high during the Dalton minimum around 1800-1820.
I plotted Armagh and sunspots together last year:
http://polistrasmill.blogspot.com/2010/08/sun-is-in-charge-as-always.html

jorgekafkazar
December 5, 2011 8:29 pm

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says.”
Ah, yes, the mandatory, PC ecco la fica that must be pronounced in every paper on every subject even remotely connected to climate.

Editor
December 5, 2011 8:31 pm

As for Martin’s claim that warming will create more couplings between the polar and sub-tropical jet-streams, I’d guess that he is thinking about warming causing the tropopause to elevate, which supposedly pushes the jet stream northward. Big scare claims a couple of years ago about such a northward movement of the jet stream causing the Mojave to extend up to San Francisco. Serious lunacy. Check it out.

Alan Clark of Dirty Oil-berta
December 5, 2011 9:07 pm

Dave says:
“So how do they explain little or no warming since 1998 and the ocean cooling trend?”
Simple: “More research will be needed. Send cheque to…”

December 5, 2011 9:22 pm

Don’t mess with mother nature – oh wait, we can’t… 😉

December 5, 2011 9:23 pm

This sounds like another piece of the puzzle. It is one that can be tested too. I like that. If we get enough of these puzzle pieces line up maybe, just maybe we will have something that resembles a reasonable explanation.

pat
December 5, 2011 10:00 pm

the Met Office makes an exception for Durban. read for all the gory details:
6 Dec: UK Daily Mail: Severe water shortages, hotter days and more floods: What the weather has in store for us in 2100 (but at least we might get bumper crops)
Millions of lives could be ‘changed forever’, MP warns
By Tamara Cohen
Despite recently dropping seasonal forecasts because they kept getting them wrong, the Met Office yesterday laid out its predictions for Britain’s weather in the year 2100…
The ‘Climate observations, projections and impacts’ report, published yesterday at the UN climate conference in Durban is the first time Britain’s weather has been mapped out for this long.
‘It comes just a year after the Met Office ditched its 90-day forecasts for the public after a predicted barbeque summer turned out to be a washout…
http://www.dailymail.co.uk/news/article-2070437/Severe-water-shortages-hotter-days-floods-What-weather-store-2100-bumper-crops.html

Steve C
December 5, 2011 10:02 pm

Wow. One jet stream can give you plenty of fun, and it looks like stacking two gives you extreme fun. Sobering to reflext that this time last century it would all have been just an “Act of God”.

Old woman of the north
December 5, 2011 11:41 pm

17C here today in subtropical Queensland and it’s December!.
Wheat crops in eastern Australia are downgraded because of low protein, and rain damage and farmers are in difficulties with rain on their harvesting program right now.

albertalad
December 5, 2011 11:55 pm

Old woman of the north says:
December 5, 2011 at 11:41 pm
17C here today in subtropical Queensland and it’s December!.
Wheat crops in eastern Australia are downgraded because of low protein, and rain damage and
farmers are in difficulties with rain on their harvesting program right now.
————
Wow – Premier Gillard’s carbon tax seems to be working even better than expected. You all cooled off very, very quickly.

December 6, 2011 12:01 am

But…but…all that windy, blowy, hurricaney stuff is down to CAGW too. Al gore said so…
/sarc

Andy
December 6, 2011 12:12 am

Bill H: “one of the biggest fallacies i can see about the AGW lie is how they ignore major factors…”
Absolutely spot-on sir: whenever I end up being roundly abused on any discussion on warmist blogs, the AGWers nit-pick over tiny details (oh, and call me things such as ‘sh*t bag’)
If you try and bring up the lack of warming since 1998 demonstrating that we are not suffering from ‘run-away warming’, the warmists go into a rage, accusing you of ‘cherry-picking’. They then proceed to link to all sorts of graphs that are cherry-picked to show warming….
I know it’s naughty, but I can’t resist: I leave the discussion by telling them all not to worry about warming as they can always just turn on the air-conditioning. I then stand back to watch various warmist heads exploding 😉

Larry in Texas
December 6, 2011 1:07 am

Wow! I’ve always wondered how much the jet stream(s) and its (their) relative position(s) contribute to the severity of storms. Down here, it doesn’t take a whole lot of temperature variability in the spring to cause major storms or tornadoes. When you get something like this “superjet,” it is scary and amazing. I wonder what next spring will bring for Texas.

December 6, 2011 1:21 am

John-X says:
December 5, 2011 at 7:40 pm
We in the formerly free world have now raised an entire generation of academics who have to have mastered this same sort of “skill”: write a paper about weather, climate, anything remotely related, and you have to throw in phrases like, “in a warmer climate,…”

Today on Dr. Lubos Motls’ blog he informs us of a current essay submitted to academia related to string theory:
“… it would apparently still be politically incorrect in the Academia to refer to my text (or me) without further disclaimers. So how is an essay on unification introduced?”
7I do not share Lubos Motl’s extreme views on politics, global warming, and sometimes not even string theory. However, he occasionally has some good physics summaries, including a recent one giving a nice history of the triumphs of unification [26].
Pasted from

December 6, 2011 1:22 am
Stephen Wilde
December 6, 2011 1:48 am

Lokks like support for my contention that climate at any given time is the combined consequence of top down solar influences on the size of the polar air masses and bottom up oceanic influences on the size of the equatorial air masses.
They are just describing one of the many forms of that interaction.
Nonetheless the final outcome of that interaction is the average net latitudinal position of the permanent climate zones which determines the rate of energy transfer from surface to tropopause and thus whether the system is showing net cooling or net warming at any given moment.
That is also what determines perceived climate in any given region.

John Marshall
December 6, 2011 2:15 am

Great post and certainly a more feasible explanation that CAGW.
Thanks for the extra insight into weather, extreme or otherwise.

Dr. John M. Ware
December 6, 2011 3:03 am

I greatly enjoyed David Hoffer’s post. Also, very illuminating article. Question: Exactly how can we, as humans, affect the jet stream? If we see the tropical jet surging northward, can we do something to prevent its intercourse with the polar jet? . . . I thought not. Even CAGW is powerless to turn aside these winds. My Geo Metro and I can surely not be blamed for any detectable effect.

Ralph
December 6, 2011 5:03 am

>>“There is reason to believe that in a warmer climate, this kind
>>of overlapping of the jet streams that can lead to high-impact
>>weather may be more frequent,” Martin says.
Interpretation:
“This has nothing to do with Global Warming, but please can I dip into the Global Warming grant budget to continue our funding (I’m just a scientific street-walker, you see) …..
.

Gail Combs
December 6, 2011 5:59 am

TrueNorthist says:
December 5, 2011 at 7:27 pm
For those interested, the following link is to various weather maps including North American jet stream maps. I use them for my own forecasting for the Pac NW/ SW BC.
http://www.weatherimages.org/data/imag192.html
____________________________________________
To quote Steve Wilde, I thought the problem was the polar jets became more “Loopy” and therefore were heading into the territory of the subtropical jets.
http://tallbloke.wordpress.com/2011/06/05/stephen-wilde-the-setting-and-maintaining-of-earth%E2%80%99s-equilibrium-temperature/
I do not know if Steve is correct or not but I do know that some of the ocean oscillations seem to have changed phase. The trade winds/ENSO connection is already well known. http://faculty.washington.edu/kessler/occasionally-asked-questions.html
And there are indications of some major changes in the Ocean Heat Content. If as Lief is always telling us, the TSI from the sun has not changed then all that extra energy had to go some where and it looks like it was tropical storms over Indonesia. It is interesting that Bob Tisdale’s last post showed that the Indian Ocean was the only ocean still warming http://wattsupwiththat.com/2011/12/05/november-2011-sea-surface-temperature-sst-anomaly-update/

Global Ocean Heat Content Is Still Flat
http://wattsupwiththat.com/2011/09/08/global-ocean-heat-content-is-still-flat/
While there’s news of ocean heat content in the Atlantic being pumped up by “leakage” from the Indian Ocean, and NOAA proclaims that La Niña is back, Bob Tisdale finds that the global ocean heat content trend since the turn of the 21st century is flat. Worse than that, it widely diverges from climate models predicting a continued rise in OHC….

The Texas ENSO Bassmaster Classic
http://wattsupwiththat.com/2011/11/12/the-texas-enso-bassmaster-classic/
A bit of a tiff developed over at Dr. Roger Pielke’s place over disagreements on the recent Texas heatwave being attributed to AGW or to ENSO. Bob Tisdale has something to say about that. Bob writes:
“In one email, Roger referred to my post about how poorly the new NCAR model hindcasts certain temperature indices, including ENSO, and Nelsen-Gammon’s decided to call my discussion about ENSO a red herring. Little does he know, I have observation-based data to back my claims.”…

Ocean Heat Content and Earth’s Radiation Imbalance
http://wattsupwiththat.com/2009/08/11/ocean-heat-content-and-earth%e2%80%99s-radiation-imbalance/
I really wish the climate scientists were as interested in looking at the real world DATA is saying as they are in trying to blame mankind for the latest hangnail.

jack morrow
December 6, 2011 5:59 am

Steven Wilde has been publishing this type of information for some time and it seems to make for a good scientific explanation for these weather events and other weather phenomena.

December 6, 2011 6:07 am

These events are the result of the surges in global circulation caused by the heliocentric or Synod conjunctions of the outer planets, Saturn in this case. The dates for the occurrences on March 22nd, 2010, April 3rd, 2011, April 15th, 2012, April 28th, 2013 etc. can be predicted and the effects of the resultant severe weather can be forecast by the expected interactions of the surges in meridional flows on a global scale for the results needed to forecast outbreaks of tornadoes in the springs, and hurricanes in the mid summer to fall periods.
Right now the other three outer planets are having Synod conjunctions in the fall, (Neptune on August 22nd, 2011, Uranus on September 26th, 2011, and Jupiter on October 29th 2011) so are affecting early fall and winter snow storm outbreaks, giving us a lull in hurricanes that peaked from the period in 1993 through 2005 when Uranus, and Neptune Synod conjunctions were occurring in mid summer.
http://research.aerology.com/natural-processes/solar-system-dynamics/
http://research.aerology.com/aerology-analog-weather-forecasting-method/
http://research.aerology.com/lunar-declinational-affects-on-tornado-production/
http://research.aerology.com/severe-weather/tornadoes/tornado-forecast-verification/
Real answers for long range forecasting of severe weather out breaks are waiting to be understood, most of the “these reported new findings” that dwell on “It’s a really fascinating global connection that occurs seven to 10 days later.” are really lunar declinational tidal effects that are enhanced due to the additional interactions of the outer planets influences that drive the overlapping of the jet stream flows that result in these mentioned effects in this paper. It would be much simpler to forecast severe weather outbreaks if they would only pay attention to timing of the outer planetary Heliocentric conjunctions, and compare past cycles to the present ones.
The frequency of these outbreak occurrences are limited to four times a year as there are only four outer planets and the predictability of their orbital interactions are know for the next 1,000 years or so. For the “CAGW Team” to say “the frequency will increase” is not possible with out adding more outer planets to the solar system.
Richard Holle

Gail Combs
December 6, 2011 6:09 am

John-X says: @ December 5, 2011 at 7:40 pm
….A few years ago I saw a documentary called “Loving Lenin,” about how the cult of lenin went on and on, long after soviet communism was dead.
There was a once-prosperous guy who lived near the university who, for a small fee would help you write your paper…
No matter the subject of your paper, it HAD to include the marxist-leninist perspective. Your interest was probably in the subject, not what the communist deities might hypothetically have pronouned about it. So, these guys, who had mastered the slogans and jargon and could insert this political jibberish on any subject anybody wrote about, were extremely valuable to the academic interested in his chosen subject, and in staying out of serious trouble…..
_______________________________________________________
The practice has now moved to the USA see “The Shadow Scholar” http://chronicle.com/article/article-content/125329

Paul Linsay
December 6, 2011 6:18 am

“Exactly how can we, as humans, affect the jet stream?” Well, that’s easy. If everyone in the Americas ran northwards and everyone on the opposite side of the earth ran southwards, by conservation of angular momentum the earth would roll southwards on the side of the Americas. Viscosity would then drag the two jets apart and prevent tornados in Oklahoma and rain in Tennessee. Problem solved and we’d all get exercise as bonus instead of sitting at our computers consoles writing grants to study AGW. Better health at lower net cost to the economy in both taxes and destruction of property.

Gail Combs
December 6, 2011 6:24 am

Interstellar Bill says:
December 5, 2011 at 7:51 pm
More likely it’s linked to the impending Grand Minimum.
Recent weather extremes have the flavor of the early 1300′s
when the Little Ice Age first hit.
Every time in the past the Earth got warm, weather was less extreme, not more.
___________________________________
HMMmmm I remember some really nasty tornadoes hitting Alabama in 1974-5 and routinely watching tornadoes form in Indiana from 1968-1972 You could still see the mile wide path of the 1965 Palm Sunday Tornado that forced wheat straw into telephone poles like they were nails.

…The second Palm Sunday tornado outbreak occurred on April 11, 1965 and involved 47 tornadoes (15 significant, 17 violent, 21 killers) hitting the Midwest. It was the second biggest outbreak on record. In the Midwest, 271 people were killed and 1,500 injured (1,200 in Indiana). It was the deadliest tornado outbreak in Indiana history with 137 people killed.[1] The outbreak also made that week the second most active week in history with 51 significant and 21 violent tornadoes…. http://en.wikipedia.org/wiki/1965_Palm_Sunday_tornado_outbreak

This was during “Global Cooling” not warming: http://justdata.files.wordpress.com/2009/12/continuitybysectors1900-2009.jpg

Gail Combs
December 6, 2011 6:32 am

davidmhoffer says:
December 5, 2011 at 8:10 pm
Both events seem to be linked to a relatively rare coupling between the polar and the subtropical jet streams, says Jonathan Martin>>>
WHAT? The polar and subtropical jet streams are COUPLING?
That’s disgusting! In public no less! They’re not even married!….
__________________________________
Perhaps you could sell this to Forbes…. http://www.forbes.com/sites/jamestaylor/2011/11/23/climategate-2-0-new-e-mails-rock-the-global-warming-debate/

Pascvaks
December 6, 2011 7:12 am

Martin and Winters have, indeed, come up with a “Gee! Look at THIS!” phenom. The shift in hurricane activity, the shift in tornadic activity, the shift in “whatever”, is not explained by the initial observation; well it isn’t unless you can also walk on water. Give them time. They’re on to something. Old Caveman saying, “Think before you clobber something.”

cjames
December 6, 2011 7:22 am

I don’t have the link to the original paper but it sounds as if they are talking about the Madden-Julian Oscillation. You can read a summary about it here: http://en.wikipedia.org/wiki/Madden%E2%80%93Julian_oscillation. Many forecasters such as Bastardi have been looking at this phenomena for years as a tool for a week long heads up on the possibility of severe weather in the US.

December 6, 2011 8:18 am

Dr. John M. Ware says:
December 6, 2011 at 3:03 am
…My Geo Metro and I can surely not be blamed…
You poor, poor man. I’m so sorry for you.

treegyn1
December 6, 2011 8:23 am

davidmhoffer says:
December 5, 2011 at 8:10 pm
Both events seem to be linked to a relatively rare coupling between the polar and the subtropical jet streams, says Jonathan Martin>>>
“WHAT? The polar and subtropical jet streams are COUPLING?….”
OK, now THAT was funny!!

Bob Moss
December 6, 2011 8:37 am

I had great interest in both of these extreme weather events because I was located directly in their paths. I hate to rain on someone’s hypothesis but the Nashville flood has a much simpler explanation than the one given.
It is common in Tennessee to have a few fronts with heavy rain pass through each year. These rain bands are typically about 100 or so miles wide east to west and can drop three or four inches of rain as they pass through. This happens every year.
These fronts typically extend southwest to northeast from the Gulf of Mexico into the upper Midwest and move west to east but also have a northward component to their motion. The more northward the motion the longer the rain band takes to move through. For example, a rain band that is 100 miles wide east to west might become effectively 200 miles wide at the angle it is moving through a given location.
In the Nashville flood the northern component of the motion was much greater than usual and the resulting direction of motion to the northeast perfectly matched the typical southwest to northeast shape of the front. So even though this front’s width and rain content was a typical heavy rain event its direction of movement turned it into an almost stationary pipe pumping moisture from the Gulf of Mexico into the Nashville area.
So instead of an hour or two of heavy rain which would be the typical situation Nashville got around 20 hours of heavy rain. I was a little east of Nashville and the front became unblocked and resumed a normal west to east movement by the time it reached me and my location received about four inches of rain from the same front.
For Nashville it was a “perfect storm” of typical weather patterns.

JPeden
December 6, 2011 8:49 am

pat says:
December 5, 2011 at 10:00 pm
“the Met Office makes an exception for Durban. read for all the gory details:…”
http://www.dailymail.co.uk/news/article-2070437/Severe-water-shortages-hotter-days-floods-What-weather-store-2100-bumper-crops.html
Despite recently dropping seasonal forecasts because they kept getting them wrong, the Met Office yesterday laid out its predictions for Britain’s weather in the year 2100…
Tamara Cohen’s Daily Mail article, no doubt ‘funded’ both by Big Oil Denier Unit and Big Oil CRU, is a riot!
Global warming would BOOST Britain’s farm crops by 10pc
Crop yields could increase on 96% of farmland
Decrease in frosty nights means crops survive [a.k.a. Earlier Springs]
Millions of lives could be ‘changed forever’, MP warns [Huhne]
By Tamara Cohen
Last updated at 1:32 PM on 6th December 2011
The coming decades will see British farmers enjoy a boom in their crop yields, it has been claimed.
If predicted rises in temperature do happen 96 per cent of farmland will enjoy an increase in productivity, according to a Met Office report.
Crops such as wheat, sugar beet, barley, potatoes and rapeseed could boom within 50 years due to the predicted decrease in frosty nights, which may also allow Britain to grow summer crops for longer.

But the tree rings will suffer horribly, explaining the “divergence”, and therefore the trees will die [Severinghaus, independent “study”] ‘very likely’ allowing the crops, weeds and unmanaged humans to run wild, before they too ‘could’ all die! Because everything that happens or could happen is “consistent with” the Precautionary Hypotheses of CO2 = CAGW = Zero.

Russ R.
December 6, 2011 10:17 am

It’s all about the temperature gradient, and its effect on Hadley cells.
In a “warming world”, this temperature gradient, is much less pronounced and we would expect less “coupling” of the two jet streams. Less pressure differential, leads to less force acting on the jet streams to break them out of their latitudinal bias. When the temperature difference is low, we have a much less active pattern, and we see that every year.
So I guess the AGW reference is more about the “cash stream” than it is about the “jet stream”.

chuck nolan
December 6, 2011 10:19 am

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says
————————-
And what might that reason be?
More money for research, improved investments, tenure, publication?
Must be some really good reason, eh?
I wonder how “high impact weather” being “more frequent” might effect windmills and solar power?
Might it reduce their output?

Stephen Wilde
December 6, 2011 11:07 am

A refresher here:
http://climaterealists.com/attachments/ftp/How%20The%20Sun%20Could%20Control%20Earths%20Temperature.pdf
For the top down solar influence on the surface pressure distribution.
and here:
http://climaterealists.com/attachments/ftp/TheSettingAndMaintainingOfEarth.pdf
For the bottom up oceanic influence on the surface pressure distribution.
and here:
http://climaterealists.com/attachments/ftp/TheUnifyingTheoryofEarthsClimate.pdf
For how the interactions occur.
Previous links to Irish Weather Online do not seem to be working at present.
There are a lot of recent papers which seem to support portions of my work but as yet no one else has tried slotting it all together jigsaw style.

Tim Ball
December 7, 2011 7:02 pm

There is nothing new about this research. I put this influence of Rossby Waves and accompanying Jet Stream on severe weather in the Canadian textbook I wrote back in 1989. I have been writing articles explaining the pattern for years. I have been showing agribusiness and farmers across North America about the pattern and how they can make useful 4 to 6 week general forecasts based on the Wave cycle.
http://drtimball.com/2011/severe-us-weather-claims-ethics-based-on-inaccurate-science/
http://drtimball.com/2011/climate-change-extremism-is-doing-its-job/
All this confirms what I said in the article for which I am being sued, the IPCC set climate research back 30 years, by promoting only one side of the debate, silencing those who questioned what was happening and producing at least two generations indoctrinated in to their false, biased and political climate science. They effectively settled science for 30 years. Here is the redacted article with the main theme intact so I don’t jeopardize my lawsuit or Anthony’s web site.
http://drtimball.com/2011/corruption-of-climate-science-has-created-30-lost-years/

Roy
December 9, 2011 4:37 pm

“There is reason to believe that in a warmer climate, this kind of overlapping of the jet streams that can lead to high-impact weather may be more frequent,” Martin says.
Except the events occur during La Ninas’ when the regional temperature is lower. Stop pandering to the AGW zealots.