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Jet stream moved northwards 270 miles in 22 years; climate change to blame?

By: Dr. Jeff Masters , 4:11 PM GMT on June 05, 2008

Climate change is forcing the jet stream higher and closer to the pole in both the Northern and Southern Hemisphere, according research published this April in the journal Geophysical Research Letters. In their paper, "Historical trends in the jet streams", researchers Cristina Archer and Ken Caldeira of Stanford's Carnegie Institution of Washington analyzed data from 1979-2001, and found that the Northern Hemisphere jet stream moved northward at approximately 125 miles per decade (270 miles during the 22-year period of the study). The jet moved higher by 5-23 meters during this period, and the wind speeds decreased by about 1 mph. Archer and Caldeira's study confirms other research showing a poleward movement of the jet stream in recent decades (Fu et al., 2006; Hu and Fu, 2007). All of these changes are consistent with the behavior of the jet stream predicted by global warming theory. For example, Lorenz and DeWeaver (2007) found poleward shifts of the jet stream by 2100 in the forecasts of 15 climate models used to formulate the "official" word on climate, the 2007 Intergovernmental Panel for Climate Change (IPCC) report. However, the authors were careful not to say how much of this shift in the jet stream was due to natural causes versus human-caused climate change. It is unknown if the jet stream has natural decades-long changes in its path that could account for the observed poleward shift.

Figure 1. The jet stream is located where the strongest winds at the top of the troposphere are found (35,000-45,000 feet high, 200-300 mb in pressure).

Archer and Caldeira note that "These changes in jet stream latitude, altitude, and strength have likely affected, and perhaps will continue to affect, the formation and evolution of storms in the mid-latitudes and of hurricanes in the sub-tropical regions." They don't specify what these changes might be. There is very little research that has been done suggesting how changes in the jet stream might affect hurricane formation and strength. One effect we may begin to see in coming decades is a reduction and/or delay in the number of hurricanes that recurve northward out to sea. Recurvature occurs when a hurricane begins to "feel" the westerly winds of the jet stream. As the jet stream continues to move northward and weaken as the globe warms, we can expect that hurricanes moving though the Caribbean will be less likely to recurve, resulting in more hurricane strikes in Mexico and Central America. Unfortunately, the quality of the Atlantic hurricane database for non-U.S. landfalls is not very good, and it will be several decades before we will be able to tell if the number of hurricane landfalls in Mexico and Central America is increasing due to a poleward shift in the jet stream.

Fu, Q., C. M. Johanson, J. M. Wallace, and T. Reichler (2006), Enhanced mid-latitude tropospheric warming in satellite measurements, Science, 312, 1179, doi:10.1126/science.1125566.

Hu, Y., and Q. Fu (2007), Observed poleward expansion of the Hadley circulation since 1979, Atmos. Chem. Phys. Disc., 7, 9367.9384.

Lorenz, D. J., and E. T. DeWeaver (2007), Tropopause height and zonal wind response to global warming in the IPCC scenario integrations, J. Geophys. Res., 112, D10119, doi:10.1029/2006JD008087.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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2:20 AM GMT on June 09, 2008
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1413. shamanTT
10:14 PM AST on June 08, 2008
Hmmm...only some slight stormkat, stormyeyes, stormyxyz activity...but I'm still off to sleep.
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1412. condesa
1:57 AM GMT on June 09, 2008
I will translate what the Weather Service is telling us here; the next and last post of the night is at 9; they do post wave/tropical updates at 10.
I do want to send thanks for listening and hearing to Pottery, StormW and Levi! Muchas gracias.
Sorry it takes so long to respond; I have to close, re load,close, re load, re load....

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1411. shamanTT
10:06 PM AST on June 08, 2008
Got the photos, thanks Pottery. Everything has been collected, and now its time to put things together. Nothing interesting in the CATL to watch, so I'm off till tomorrow.
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1410. moonlightcowboy
9:10 PM CDT on June 08, 2008
Evidently, WU is still having some troubles. Blogholes, slow-posting. No problems on other sites. So, maybe they'll get all the kinks worked out soon...sure is aggravating though!
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1409. moonlightcowboy
9:08 PM CDT on June 08, 2008
See, Pottery. You get Cadillac answers from the guru. Thanks, StormW, and have a good sleep!
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1408. pottery
10:05 PM AST on June 08, 2008
Much appreciated, Storm.
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1406. pottery
10:04 PM AST on June 08, 2008
I agree with you Shaman. It just does not yet "feel" like it.
And no, not a leaf !!
Did you get the photos?
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1404. stormyeyes
1:56 AM GMT on June 09, 2008
Can anyone on the blog tell me why ya'll
don't like Stormkat? He picked me up from
the airport in NO on my way home from working
in CA. then we went to Destin for the rest
of the weekend...He was a totally respectable
guy, he knows how to treat a girl that's for
sure...was just curious why no one here likes
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1403. pottery
9:56 PM AST on June 08, 2008
Thank you MLC. I had some of that figured out, but you have filled some gaps.
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1402. moonlightcowboy
8:58 PM CDT on June 08, 2008
Have a good sleep, Baha. Glad you got some precip, too!
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1401. pottery
9:49 PM AST on June 08, 2008
Thank you for that loop, StormW
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1400. BahaHurican
9:53 PM EDT on June 08, 2008
Good night all. Hope you have a great week every-wise!
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1398. moonlightcowboy
8:44 PM CDT on June 08, 2008
Of course, I see StormW is in here and fully qualified to answer your question, but I'll take a small stab at it.

Climatologically, we're not due to get anything developing from the cATL. Some areas have slightly cooler temps, but that's changing as the ITCZ moves northwards. It's changing fairly rapidly, too. There's little to no SAL and dry air to boot. And, with the frequency and organization of some of these twaves, it would not surprise me to see some early developing CV waves, especially towards mid-july, perhaps a sneeker before then.

As far as the winds, a system develops from a surface low. If there's not a strong shear presence at the surface, a storm has time to develop, build and may overcome temporary unfavorable upper level shear. In early development, shear is more important at the surface. The shear you describe is from the westerlies at the higher levels, and yes, that can be an unfavorable element to a developing storm. I also understand that the westerlies will also move somewhat further north, too, climatologically and weaken as the season moves forward. However, these storms need venting, outflow as they fully develop - so some vertical shear aids and is necessary for a storm to mature. Still, if upper level shear is strong, it can keep blowing the tops off a storm and keep it from stacking vertically prohibiting further development.

That's the two cents worth, doodle-bug version. StormW can give you the Cadillac answers! LOL
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1397. Skyepony (Mod)
1:50 AM GMT on June 09, 2008
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1396. Skyepony (Mod)
1:46 AM GMT on June 09, 2008
Last week total rain amounts.

StormW~ Thanks for posting the papers. Good stuff about the types, the moving south. Always wondered.
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1395. shamanTT
9:42 PM AST on June 08, 2008
Pottery, have the leaves started appearing on the Calabash tree? Still doesn't quite feel like the rainy season.
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1394. pottery
9:45 PM AST on June 08, 2008
Not waterlogged at all. But the grass and plants did green up a bit already ( amazing how quik that happens)
Overall we got 1.25 inches in 3 days. Made a big difference.
Looking for more, but the horizon is clear.

What is yr. take on my post 1386 ?
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1393. moonlightcowboy
8:41 PM CDT on June 08, 2008
LMAO, Pottery! You must be a problem solver! (talking to one's self) ;P

You didn't get water-logged from that bit of rain, did you?
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1392. pottery
9:32 PM AST on June 08, 2008
Post 1386.
Pottery, that is a ridiculous series of erroneous assumptions, arrived at by you looking at one very small aspect of the systems and modulations that drive and impact the formation of Trop. Stormzis.
Please refrain from posting stuff like that, without first performing analyses of the Global Condition of coral polyps and Madagascan newts , in the future..

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1390. pottery
9:25 PM AST on June 08, 2008
Could be, I'm in a blog-void..........
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1389. BajaALemt
8:18 PM CDT on June 08, 2008
Nice view of the Cheyene tornado warned cell on Steve Miller's cam if anyone's interested

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1388. pottery
9:20 PM AST on June 08, 2008
Hello ??
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1387. primez
1:11 AM GMT on June 09, 2008
Nevermind. It's 9 right now, and I didn't even realize it. That might explain the lower temperature a bit.
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1386. pottery
9:02 PM AST on June 08, 2008
The Tropical Atlantic is still being affected by upper level winds that are not condusive to any Trop. Development, IMO.
Below 10n, the ULW is tending southerly, which is helping to raise the ITCZ northward.
Above 10n, all the way to 25n, the ULW is still predominately Westerly, blowing everything back toward the Azores High.
It would be very difficult for any Wave to develop under these conditions..

Am I reading this all correctly ??
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1385. primez
1:07 AM GMT on June 09, 2008
WOW! because of the storm that passed through todays, we just received a 20 degree drop in temperature!
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1384. nrtiwlnvragn
9:07 PM EDT on June 08, 2008
1377. pottery

Model Analyses and Forecasts Caribbean 12 UTC GFS
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1382. all4hurricanes
12:56 AM GMT on June 09, 2008
There really isn't much in the tropics

Another scorcher today 50% humidity and 92 degrees
I spent all day on a boat and I think I got sunburned
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1381. Levi32
4:52 PM AKDT on June 08, 2008
Unfortunately that trough and associated moisture are going to be sitting over Mexico for at least several more days. I am not sure what local rainfall amounts are like but I imagine they have a lot more coming as that area of disturbed weather continues to linger there. I hope everyone stays safe and the flooding abates soon.
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1379. BajaALemt
7:51 PM CDT on June 08, 2008
Grey....the cam's back up
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1378. GeoffreyWPB
8:49 PM EDT on June 08, 2008
My thoughts and prayers go out to all who are experiencing severe weather, no matter where.
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1377. pottery
8:47 PM AST on June 08, 2008
I think Condesa is looking for more than a sat image
, Anyone want to venture to give some rain forecasts, duration forecasts, I think would assist them in Mex. apparently.
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1376. tallahasseecyclone
12:48 AM GMT on June 09, 2008
The blog entry just starts getting messy when he is on vacation. I am sure he would have had an entry abou the severe weather if he did post something.
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1375. BajaALemt
7:47 PM CDT on June 08, 2008
Not at all uncommon for Doc M to blog about severe outbreaks *shrugs*
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1374. Greyelf
7:44 PM CDT on June 08, 2008
RE: 1346. BahaHurican

Unfortunately, shortly after I posted the link, it went "no stream available". Not sure why, but I promise, while it was up, it was pretty spooky looking. That chaser still isn't streaming again yet either.

Edit: as of 7:55, the stream was active again. Still pretty dark.
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1373. pottery
8:45 PM AST on June 08, 2008
WOW Condesa.....
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1372. pottery
8:26 PM AST on June 08, 2008
Tallahassee, we ALL come here looking for info on Tropical Storms.
Fortunately/unfortunately, there are none. Since lots of people here are interested in ALL aspects of weather, and tornados are Etc etc etc.......
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1371. Levi32
4:43 PM AKDT on June 08, 2008
1370. condesa 4:42 PM AKDT on June 08, 2008

Here's a satellite pic if that's what you wanted. Stay safe down there.

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1370. condesa
12:42 AM GMT on June 09, 2008
Evenin' all-
Old Mexico is drowning and flooding all over, blame it on the do nothing twave and the low pressure, but don't say there's nothing going on in the Gulf or E Pacific or tropics. Whatever is going on may not be dramatic or a hurricane but it is washing mountains, roads,topsoil, rivers and people and their homes away.
Check out the diluvial stuff on the Pac coast- Chiapas, Guerrero and Oaxaca and around Tamaulipas.
Most of us down here only have dial-up; I pay for broad-band, but I only get dial-up speed, when I'm lucky. Occasionally I have a decent siganal, but it's rare.
I have only had electricity a few hours off-and-on since day before yesterday and I'm in an immensely priveledged area. I know I'm grouchy but I've been hearing the National Electric Commission Emergency line people tell me my street and entire neighborhood don't exist and therefore they can not repair the lines.
Check out the storms happening down here, and shoot us a picture if you can, somebody. It's hard for me and other many people to access and load pages.
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1369. Levi32
4:40 PM AKDT on June 08, 2008
1366. tallahasseecyclone 4:38 PM AKDT on June 08, 2008

Take a look at the Atlantic......see anything much to talk about? Besides that ULL that we have been covering for some time now that might provide Florida with much-needed rain. There isn't really an official blog for severe weather, and I can't speak for anyone else but I see no problem with discussing some unique, not to mention DANGEROUS situations during moments of quiet in the tropics.
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1368. GeoffreyWPB
8:40 PM EDT on June 08, 2008
There are no tropical threats....anywhere! When they happen...this is the place to be.
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1367. GeoffreyWPB
8:39 PM EDT on June 08, 2008
3 killed as severe storms flood Midwest
Published: 6/8/08, 8:00 PM EDT

(CNN) - At least three people died Sunday as heavy rains continued to pound the American Midwest, flooding towns from Iowa to Michigan and threatening levees.
Two delivery workers for The Grand Rapids Press in Michigan were killed Sunday morning after their car fell into a deep ravine created when a rain-swollen creek washed out a road, according to a story posted on the newspaper's Web site.

Several storms plowed eastward through central Michigan, downing trees and power lines all over Ingham County, said Sgt. Mike Perez, the county's emergency management program manager. One woman in a Lansing city park was struck by a tree, though her injuries were not life-threatening.

Meanwhile, storms in Nebraska spun out an early-morning Omaha tornado about a quarter-mile wide that moved northeast.

Jeff Leanna, a member of the fire department's community response team, submitted photos from the scene to CNN showing housing pushed off their foundations, a flattened trailer home and several businesses with their roofs blown off and windows blown out.

"The damage is spotty," he said, but power outages were widespread. "It sort of came out of nowhere. The tornado touched down before the sirens went off."

And heavy rains, as much as 11 inches in some communities, flooded central Indiana over the weekend, testing levees and forcing many to find safety atop rooftops.

At least one person died as the result of rising waters, according to a police spokesman in Columbus, Indiana. The victim was swept away while driving a car through flood water.

The worst-hit areas were communities about 25 miles south of Indianapolis and further west in Terre Haute, with most towns receiving 6-10 inches of rainfall, said John Hendrickson, a meteorologist with the National Weather Service.

He said some affected areas hadn't seen a such flooding for 100 years.

Officials were worried about two levees as water spilled over them in Johnson County, one of the hardest hit areas. But they have so far held up.

A small community downstream from the levee at Princess Lake was trapped as roadways leading out remained submerged Saturday afternoon, Hendrickson said. A hospital in Johnson County was also flooded.

A levee burst in the Iowa town of Parkersburg, still reeling from a deadly tornado that struck two weeks ago, according to the National Weather Service. Flooding from the levee break shut down portions of three interstate highways.

Flood waters continued to rise throughout Iowa on Sunday, with the northern part of the state receiving up to 5 inches of rain from a single afternoon storm, said Bret Voorhees, spokesman for Iowa Homeland Security and Emergency Management.

Waters were expected to crest mid-week at the earliest, he said, adding that at least 200 people were displaced across the state.

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1366. tallahasseecyclone
12:36 AM GMT on June 09, 2008
Deleted sorry
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1365. Patrap
7:33 PM CDT on June 08, 2008

Quad Cities, Base Reflectivity 0.50 Degree Elevation Range 124 NMI
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1364. Patrap
7:30 PM CDT on June 08, 2008
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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