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.'”
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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.
Darn, I forgot to say thanks for a great article…
Thanks for a great article!
I can’t believe I forgot the link… Must sleep…
http://www.weatherimages.org/data/imag192.html
“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?
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.
Hang on a tick, let me shake the old 8-ball………
Ah, yes, “Weather, not climate.”
“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).
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?
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?
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?
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…
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.
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.
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.?????
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
“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.
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.
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…”
Don’t mess with mother nature – oh wait, we can’t… 😉
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.
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
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”.
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.
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.
But…but…all that windy, blowy, hurricaney stuff is down to CAGW too. Al gore said so…
/sarc