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

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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.

References
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

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1364. Patrap
7:30 PM CDT on June 08, 2008
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1363. Patrap
7:27 PM CDT on June 08, 2008
Suppose & Reckon thats a Roger...
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1362. Levi32
4:25 PM AKDT on June 08, 2008
1360. Patrap 4:25 PM AKDT on June 08, 2008

Pat I think that is indeed an error on the radar's part. There's no real storm activity in the area where the vortex was located, and it's also very close to the radar tower itself, which means it's likely that there are some erradic velocity readings that are confusing the radar.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1361. mermaidlaw
12:24 AM GMT on June 09, 2008
I sure hope everyone is safe in these storms!
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1360. Patrap
7:24 PM CDT on June 08, 2008
Storm capable of producing a tornado
Tornado Vortex Signature (AMA_R7)
ID: R7
County: Carson
Max: 48 dBZ
Top: 3,000 ft.
VIL: 1 kg/m²
Chance of Severe Hail: 0%
Chance of Hail: 0%
Max Hail Size: 0.00 in.
Speed: 4 knots
Direction (from): SE (140)

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1359. Levi32
4:22 PM AKDT on June 08, 2008
Here's the worst of the bunch. Storm M8 on this image. Max Dbz of 92.....max VIL of 96....incredible. And in case this is an error....I checked the same storm on the other station. It's only 72dbz....but still has a VIL of 86. That's causing some very serious hail.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1358. mermaidlaw
12:23 AM GMT on June 09, 2008
What does that mean Pat?
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1357. Patrap
7:20 PM CDT on June 08, 2008
The new softened radar mode is welcomed.
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1356. mermaidlaw
12:19 AM GMT on June 09, 2008
Thanks Levi!
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1355. Levi32
4:15 PM AKDT on June 08, 2008
Can see you too mermaid lol.

Here's a visible shot of the storms, and you can see the general area they're in. The storm tops aren't all that high, but they're obviously generating some ferocious weather.

Member Since: November 24, 2005 Posts: 635 Comments: 26594
1354. pottery
7:53 PM AST on June 08, 2008
Good evening./ All is very calm and quiet in the Tropics I see.
Nothing in the Atl but a mild wave.
Nothing in the GOM but a threat for Thursday or so

More Tornadic weather in the Mid States ? Horrors man.
Member Since: October 24, 2005 Posts: 0 Comments: 24233
1353. mermaidlaw
12:12 AM GMT on June 09, 2008
Thank you 456, and dude!
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1352. stormdude77
8:11 PM AST on June 08, 2008
I can see you, Mermaid!
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1351. Weather456
8:10 PM AST on June 08, 2008
1348. mermaidlaw 8:10 PM AST on June 08, 2008
Can anyone see me here? Thanks!


Clearly visible
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1350. mermaidlaw
12:10 AM GMT on June 09, 2008
Thanks Levi! WOW, I sure hope people stay safe in that area!
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1349. Stormchaser2007
8:09 PM EDT on June 08, 2008
Theres no way on earth that theres 90+dbz or even 80+ storms out there....obviously theres some thing wrong with the radar tower.
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1348. mermaidlaw
12:09 AM GMT on June 09, 2008
Can anyone see me here? Thanks!
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1347. Levi32
4:07 PM AKDT on June 08, 2008
It's great to see you too mermaid. Those storms are crossing over from NE Texas into southern Oklahoma. As for WHAT they are.....if the radar isn't goofing up.....well..they're some dang nasty storms lol. The tail-end of that cold front in the plains is really exploding in that area. We'll probably see some big hail reports soon.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1346. BahaHurican
8:04 PM EDT on June 08, 2008
greyelf, it's saying no stream available . ..
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1345. mermaidlaw
11:53 PM GMT on June 08, 2008
Levi it is so good to see you here! What IS that? and where is it?
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1344. Weather456
7:58 PM AST on June 08, 2008
1315. StormW 7:18 PM AST on June 08, 2008

Ur post is solid with me. But an upper level ridge (anticyclone) should result when a warm-core develops in the upper levels due to expansion of geopotential heights* over the disturbance relative to the surrouding enviroment.

*This expansion occurs due to expanding air within the warm-core.

Just my little addon.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1343. Skyepony (Mod)
11:58 PM GMT on June 08, 2008
The hail icon outta the yellow & green stuff to the left would say not calabration problem.
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1342. Greyelf
6:59 PM CDT on June 08, 2008
Here's streaming video from a chaser in the area. It don't look any too pretty. Link
Member Since: June 5, 2007 Posts: 18 Comments: 838
1341. Levi32
3:56 PM AKDT on June 08, 2008
1338. pearlandaggie 3:54 PM AKDT on June 08, 2008

I dunno......it's possible......here's the same storms from another radar, though they're near the edge of the scanning range.



Both radars are reporting VILs of 75+ though, which means those storms are generating enormous hail (4+ inches) no matter how strong the echoes are.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1340. Greyelf
6:56 PM CDT on June 08, 2008
My goodness... look at all the white.

Member Since: June 5, 2007 Posts: 18 Comments: 838
1339. Levi32
3:53 PM AKDT on June 08, 2008
Never ever seen so much white on the NWS legend before. Those things are exploding right now.......rain rates over 3 inches per hour. Link
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1338. pearlandaggie
11:53 PM GMT on June 08, 2008
1334. hopefully, it's a calibration problem! otherwise.......
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1337. Skyepony (Mod)
11:51 PM GMT on June 08, 2008
Oh my Levi...
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1336. GeoffreyWPB
7:52 PM EDT on June 08, 2008
MADISON, Conn. (AP) - Five people are in the hospital after lightning struck a pavilion at a Connecticut state park.

State environmental department spokesman Dennis Schain says the lightning struck shortly after 5 p.m. Sunday. He says one of the victims at Hammonasset Beach State Park is "very seriously" injured.

Strong thunderstorms moved through the state Sunday afternoon. Thousands of people in Connecticut lost power.
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1335. Skyepony (Mod)
11:27 PM GMT on June 08, 2008
An Upper level low is low pressure high in the atmosphere. Many times they are parked over highs. The best conditions for the ULL to work to the surface & turn into a surface low is for it to tap into warm, very moist air over warm water & the surface high to move out. This ULL had some dry wrap up in it yesterday. Looks like it may tap a little cuba convection, which in return might bring more rain to Fl tommarrow. It generally takes 4 days for an ULL to work to the surface, it can happen stationary or moving. An ULL isn't really tracked like a storm so it's not really warm or cold core. For example today's 12Zgfs doesn't have the ULL. It also doesn't have it as a possible future storm, so it expects it not to transition. It's fairly rare to see one tranision.
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1334. Levi32
3:50 PM AKDT on June 08, 2008
You guys ever seen anything like this?

Member Since: November 24, 2005 Posts: 635 Comments: 26594
1333. pearlandaggie
11:46 PM GMT on June 08, 2008
bootsie, your cat should be named Oreo! LOL

/just like my brother's! :)
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1332. Bootsie1
6:38 PM CDT on June 08, 2008
we need rain badly, we are so dry.
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1331. cchsweatherman
7:39 PM EDT on June 08, 2008
Member Since: April 14, 2007 Posts: 8 Comments: 5169
1330. GeoffreyWPB
7:38 PM EDT on June 08, 2008
Wierd thing was surfmom...Frances and Jeanne passed just a little north of me...lost power for a long time...but that was it. Wilma came in from the west...and I couldn't of cared less. Ripped my roof off. You never know!!!
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1329. surfmom
11:38 PM GMT on June 08, 2008
g'nite
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1328. surfmom
11:30 PM GMT on June 08, 2008
thanks for the acknowledgment! Must add my mate is very much a believer in self-reliance and being prepared. So we actually have/had a good time setting things up.
going back to help friends after frances and Jeanne was a real eye opener. I drove up and down all the streets, looked at what worked, what didn't work, what people had that made their quality of life at a difficult time better -
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1327. GeoffreyWPB
7:35 PM EDT on June 08, 2008
Good point pearland...After living in West Palm area all my life..and through many hurricane threats....never thought anything bad could happen. IT CAN HAPPEN TO YOU!!!
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1326. pearlandaggie
11:33 PM GMT on June 08, 2008
amen, Geoffrey! and pay for the dayum flood insurance, too! :)
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1325. GeoffreyWPB
7:30 PM EDT on June 08, 2008
I know that now...I was caught with my proverbial pants down after Wilma. Although I qualified under all circumstances...I got screwed. To all.....have or get homeowners ins. including Loss Of Residence!!!
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1324. pearlandaggie
11:29 PM GMT on June 08, 2008
1302. looks to be a wet day in cuba (or is it cooba?)! i guess that's typical for this time of year, though..
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1323. extreme236
11:29 PM GMT on June 08, 2008
Oh I'm sorry, its not Michael Brown, its "Brownie"

"Brownie, you're doing a heck of a job,"
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1322. pearlandaggie
11:27 PM GMT on June 08, 2008
1320. LOL. i wouldn't expect much out of McLame or nObama!

the best thing you can do for you and your family is to prepare on your own like the government is never going to come. surfmom has set the bar high this year!

(also see patrap's preparedness website)
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1321. InTheCone
7:26 PM EDT on June 08, 2008
Thanks Storm, I've always wondered about that and why it so rarely happens.


Also - Thanks to 456 for his informative blog on easterly waves!
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1320. extreme236
11:25 PM GMT on June 08, 2008
1317.

Probably either one. It would be hard to appoint someone worse than Michael Brown.
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1319. pearlandaggie
10:51 PM GMT on June 08, 2008
alright, weather geniuses! any idea when the pattern of lows over New Mexico and the high over the Atlantic will break? i know the high is typical for this time of year, but i'm really getting tired of the wind. any ideas?
Member Since: September 14, 2007 Posts: 3 Comments: 3963
1318. GeoffreyWPB
7:20 PM EDT on June 08, 2008
StormW...Thank you so much for the in-depth and detailed answer to my question. That’s a definite copy and paste on my personal hurricane info. page. You are the best...as all of us know!
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1317. GeoffreyWPB
7:18 PM EDT on June 08, 2008
Any opinions who would run a better FEMA..a McCain or Obama appointment?
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1316. STORMTTOP
11:18 PM GMT on June 08, 2008
Looks like they may have it cranked up in sensitivity.
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1314. STORMTTOP
11:16 PM GMT on June 08, 2008
DTH = Day Time Heating
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.