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

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 714 - 664

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32Blog Index

714. pearlandaggie
12:20 AM GMT on June 07, 2008
709. you can have the DAYUM surf...it's supposed to be calming down right about now as the offshore fishing season really kicks into high gear! i'm starting to resent the sight of surfboards! LOL
Member Since: Posts: Comments:
711. TerraNova
8:18 PM EDT on June 06, 2008
Drak or StormW, if you can answer this I would greatly appreciate it...what is the current QBO phase (easterly or westerly) and what is the forecast? Thanks in advance for any answer.
Member Since: Posts: Comments:
709. surfmom
12:16 AM GMT on June 07, 2008
pearl&aggie - the gulf looked like a lake today -- are you looking to get some surf over there? giggle
Member Since: Posts: Comments:
708. Drakoen
12:16 AM GMT on June 07, 2008
706. TerraNova 12:16 AM GMT on June 07, 2008
Evening StormW and all!

Strong tornadic supercell in Missouri at the moment, moving over mostly rural area. Very impressive structure.


Yea. Nice radar hook and velocity.
Member Since: Posts: Comments:
707. surfmom
12:12 AM GMT on June 07, 2008
my son got a job as a commercial diver (welding, ship husbandry, marine construction) will be getting work all over the carib. young son has seacamp in the keyes. I am calm (at least at this time) knowing I have the blog for a resource - but it could be a nail bitter this year
Member Since: Posts: Comments:
706. TerraNova
8:15 PM EDT on June 06, 2008
Evening StormW and all!

Strong tornadic supercell in Missouri at the moment, moving over mostly rural area. Very impressive structure.

Member Since: Posts: Comments:
704. pearlandaggie
12:11 AM GMT on June 07, 2008
the arabian sea is looking like the GoM as of late! LOL



alright, maybe not QUITE that bad! :)
Member Since: Posts: Comments:
703. surfmom
12:10 AM GMT on June 07, 2008
hey StormW - good to see you. getting some drizzle rain SRQ/FL- hope it builds up a little more
Member Since: Posts: Comments:
701. pearlandaggie
12:09 AM GMT on June 07, 2008
top of the ev'nin' to ya, stormW :)
Member Since: Posts: Comments:
699. surfmom
12:06 AM GMT on June 07, 2008
It's intensified - in surfmom speak LOL
Member Since: Posts: Comments:
698. pearlandaggie
12:03 AM GMT on June 07, 2008
is "random chaos" redundant? LOL just kiddin'
Member Since: Posts: Comments:
697. surfmom
12:04 AM GMT on June 07, 2008
I have a file folder, whenever the talk gets very tech. I often print it out for review and reference --still a year into this and all I know is how much I don't know
Member Since: Posts: Comments:
696. Drakoen
12:03 AM GMT on June 07, 2008
694. surfmom 12:03 AM GMT on June 07, 2008
Drak - you are so smart - plowing through the explanation/information to understand these concepts exhausts my brain LOL I have to read, re-read and then read again whew and even though this is science it still seems like RANDOM CHAOS


You have to study the information enough to retain it. You can't study to just remember for that moment.
Member Since: Posts: Comments:
695. pearlandaggie
12:00 AM GMT on June 07, 2008
688. i find the wave propagation into the red sea and the gulf of oman/persian gulf interesting. i would have thought the narrow straits at the PG/RS entrances would have attenuated the waves more....

disregard this comment...i was looking at the wrong pic! the current pic makes a LOT more sense!
Member Since: Posts: Comments:
694. surfmom
12:00 AM GMT on June 07, 2008
Drak - you are so smart - plowing through the explanation/information to understand these concepts exhausts my brain LOL I have to read, re-read and then read again whew and even though this is science it still seems like RANDOM CHAOS
Member Since: Posts: Comments:
693. fire831rescue
11:59 PM GMT on June 06, 2008
I'm baaaaack! What's going on in the tropics today? Anything new I need to worry about?
Member Since: Posts: Comments:
692. pearlandaggie
11:49 PM GMT on June 06, 2008
688. i don't know if this helps answer your question...



edit: i'm sorry...i posted the wrong picture at first! doh! (_8(|)
Member Since: Posts: Comments:
691. surfmom
11:57 PM GMT on June 06, 2008
Thunder i hear thunder tis music to my ears...hope there is more rain a coming, my thirtsy mango, avo, mac nut,persian lime, 7 orange trees have their branches outstretched hoping for some cooling rain
Member Since: Posts: Comments:
690. Drakoen
11:54 PM GMT on June 06, 2008
687. BahaHurican 11:47 PM GMT on June 06, 2008
682. Drak

This supports my hypothesis, then. I'm still trying to figure out how such a low-trending ITCZ will impact storm formation and path.


Its bad and good depending on how you look at it. Its bad in a sense that without the poleward movement of the monsoon trough dry air maybe more dominant through the CATL indicating less instability. However, sometimes systems in the northerly fixed ITCZ have a hard time breaking away from the ITCZ and exhibit broad circulations and die upon leaving the ITCZ. Thats not to say though that tropical depressions can't form within the ITCZ. The southerly position of the ITCZ would allow systems to be more reliant on themselves in allowing their circulation to pick up moisture from the ITCZ. Typically only strong waves with vigorous circulations are able to do this similar to the ones we have been seeing.

It's a matter of instability and stability. Poleward vs westward and weak waves vs. strong waves.
Member Since: Posts: Comments:
689. surfmom
11:52 PM GMT on June 06, 2008
What unsettles the guys I spoke with is that they are unfamiliar w/the patterns they are seeing --so they are unsure of what future weather may be. It's a matter of Eyes Wide Open and being calmly prepared with plans & materials --as well as hanging out here
Member Since: Posts: Comments:
688. BahaHurican
7:47 PM EDT on June 06, 2008
aggie, How much of the wave action in the Arabian sea heads west across Central Africa?
Member Since: October 25, 2005 Posts: 19 Comments: 21883
687. BahaHurican
7:46 PM EDT on June 06, 2008
682. Drak

This supports my hypothesis, then. I'm still trying to figure out how such a low-trending ITCZ will impact storm formation and path.
Member Since: October 25, 2005 Posts: 19 Comments: 21883
686. pearlandaggie
11:35 PM GMT on June 06, 2008
from the looks of this, the T numbers for the disturbance in the Arabian Sea seem to have fallen off...

DATE/TIME LAT LON CLASSIFICATION STORM
06/2030 UTC 20.4N 60.2E T1.0/1.5 99A
06/1430 UTC 20.1N 60.3E T1.0/2.0 99A
06/0830 UTC 19.8N 62.2E T1.5/2.5 99A
06/0230 UTC 19.5N 61.4E T2.5/2.5 99A
05/2030 UTC 19.5N 62.8E T2.0/2.0 99A
Member Since: Posts: Comments:
685. KEEPEROFTHEGATE (Mod)
7:30 PM EDT on June 06, 2008
178 days remain
Member Since: Posts: Comments:
684. presslord
7:30 PM EDT on June 06, 2008
yea Baha...those guys and gals are a wealth of information...sometimes I feel we get so caught up in scince/technology we forget that understanding this is as much art as anything else...I love the quote from thestormtracker.com: meteorology can only "approximate chaos"....
Member Since: August 13, 2007 Posts: 0 Comments: 10480
683. BahaHurican
7:27 PM EDT on June 06, 2008
press,

u guys make me want to go out and talk to some old timers . . . (kinda hard to do with my current work load / schedule). I'd be interested to see what some of our island fishermen have to say about current conditions and their forecast of potentially stormy weather.
Member Since: October 25, 2005 Posts: 19 Comments: 21883
682. Drakoen
11:25 PM GMT on June 06, 2008
The ITCZ is a monsoon trough that is formed with the convergence of the tradewinds from the North Alantic and south Atlantic as they parallel with the low level easterlies. The tradewinds are lighter at the meeting as thats when both highs have the weakest reach. The ITCZ and highest area of SST's are said to be co-existant in the CATL which is one factor of the ITCZ position. As you know with high pressure, the winds expand outward from the center and are generally lighter over the center than around periphery of the high pressure center. A strong A/B promotes stronger tradewinds and you have more winds pushing down south closer to the equator. With a weaker A/B high you have lower pressures and not as much force pushing southward.
Member Since: Posts: Comments:
681. presslord
7:12 PM EDT on June 06, 2008
yup...I just find it fascinating....
Member Since: August 13, 2007 Posts: 0 Comments: 10480
680. surfmom
11:12 PM GMT on June 06, 2008
Nice feeding the horses late this afternoon. They were so happy for the showers - in stead of the place feeling like a dust bowl, it was cool, green refreshing -this is the weather pattern I wish we always had.......years back that is how it always was...nap time=thunder showers - like clockwork...then it seem to fade away
Member Since: Posts: Comments:
679. surfmom
11:08 PM GMT on June 06, 2008
Well, Presslord - we've discussed this before...the locals fishermen, dive captains that I know around my "hood" SRQ/Tampa are saying the same thing. Mostly what I get is that "things be different" like currents and wind - I notice the wind --odd things like the set up that made waves the last two weeks in May.
Member Since: Posts: Comments:
678. presslord
7:03 PM EDT on June 06, 2008
it's interesting...all the old Captains around here are predicting doom and gloom this year...based on colors of the water, movement of fish, crabs, seaweed...I don't pretend to know what all...but it's pretty cool that the science seems to agree....
Member Since: August 13, 2007 Posts: 0 Comments: 10480
677. hurricane23
6:59 PM EDT on June 06, 2008
667. Smyrick145 6:17 PM EDT on June 06, 2008
Hurricane 23,
I've been on this blog for the last couple years, I never post much but rest assure I check in 10 to 15 times a day. One thing I have always noticed about you is your conservative mannerism. However, lately I feel you have a true concern for the upcoming year. Am I over analzying this or could this be one hell of a year? P.S. I know most people don't buy into preseason hype, but we are almost in the middle of June now and we should start to see conditions setting up for the upcoming season. Any thoughts are very much appreciated.

Iam not one that creates outlooks but indeed there are several factors this season that concern me here are a few, first and foremost as you can see the tropical atlantic has been slowly but steadily continued to warm starting of by the eastern atlantic meaning areas of the african coast which could cause problems as we move into capeverde season.In general most of the tropical atlantic is running above or slightly above normal sst wise.Thankfully hurricane heat potential has been slow to come so far this year but over the past couple of weeks its begun to catch up.

Shear is always the hardest to forecast. In the long term we can't decipher with accuracy what impact shear will have on a specified region but we can use long range atmospheric forecasts (such as the ENSO, jet streams, long waves, etc) to get an idea of what patterns we could expect. However, more times then not these long range forecasts are also not accurate to what the models suggest. An example would be using the GFS long range, we can determine if areas will receive an above normal amount of precipitation. So, if South Florida is expected to have an above amount of precipitation for the next 2-3 months, we could imply that this is the result of a series of fronts and low pressure systems impacting the area. With this knowledge, we could assume that this same region will experience above normal amounts of shear due to this fact. But, as stated above, if the long range forecasted assemblies are incorrect then our synopsis of above normal shear could also be incorrect.

As for the ENSO i truly believe neutral conditions will prevail through the majority of this hurricane season with a 50/50 chance of a weak nino developing later in the year.

Overall no matter what the forcasted number of storms are YOU MUST have a hurricane plan in place if you area is vulnerble to tropical cyclones and keep in mind even a season with 1-1-1 has the potential for catastrophic results (ie, 1992).The last 2 seasons have been kind to the united states but as of now my thinking is that might change in the coming weeks and months.

Here are TSR'S updated numbers along with CSU.CSU's lastest updated forcast is a nice read and i recommend you to read it and also look through there new Interactive Landfall Probability Display.Nice tool. Adrian
Member Since: Posts: Comments:
675. pottery
6:51 PM AST on June 06, 2008
Hi all. I'm in and out.
The wave at my eastern doorstep still looking good for showers and squall conditions late tonight and Sat.
Seems to be inclined to move a little north in the coming 12 hrs, mostly missing the mainland.
Conditions now clouding over a bit.
Enter ' piarco ' in the weather box top left of this page for local conditions as they change.
BBL
Member Since: October 24, 2005 Posts: 0 Comments: 24233
674. BahaHurican
6:50 PM EDT on June 06, 2008



This is OPC's 96 hour forecast. Look at the location of the high pressures. They're way out at the edges of the basin, but still very low. There HAS to be some kind of correlation between the location of these surface highs and the location of the ITCZ . . . .
Member Since: October 25, 2005 Posts: 19 Comments: 21883
673. BahaHurican
6:47 PM EDT on June 06, 2008
Here's a question for those of u who have been observing the wave train crossing the ATL for the last few weeks.

What impact do you think the continued low position of the ITCZ will have on track, strength, intensification etc of July / August systems? I'm asking because I haven't seen the ITCZ so low this far into June since I've been looking at the maps (about 7 years now).
Member Since: October 25, 2005 Posts: 19 Comments: 21883
672. BahaHurican
6:43 PM EDT on June 06, 2008
670.AWx .. .

I'm also looking at that Twave that's getting ready to exit the CAR, stage left. Seems that whole area is under cloud cover, suggesting there's enough of an interaction with the quasi-stationary Colombian low for the Twave to keep going. Maybe that one will make something of itself in the more favorable EPac conditions . . .
Member Since: October 25, 2005 Posts: 19 Comments: 21883
671. BahaHurican
6:32 PM EDT on June 06, 2008
668. Smyrick145 6:19 PM EDT on June 06, 2008
Also any other thoughts other than Hurricane 23 are welcome.


I agree with 23 that there is a lot to be concerned about this year, primarily because so many factors which can contribute not only to tropical cyclone formation but also to increased landfall risk seem to be in place. Various bloggers have talked about some of them - the Cape Verde wave train, weak la Nina to neutral ENSO conditions, normal sea temperatures, location of the AB high - all these suggest that this season could be a difficult one.

The thing is, we can't really KNOW for sure. That's why bloggers like hurricane23 and Patrap stress the importance of preparation. Whether the storm comes to you depends on variable weather / climate conditions which we don't fully understand. Your best defense is to be knowledgeable and prepared.
Member Since: October 25, 2005 Posts: 19 Comments: 21883
670. AWeatherLover
10:37 PM GMT on June 06, 2008
669-baha, agreed. Definitely an area to watch. Hope it holds together, I know a lot of people could use the rain, myself included.
Member Since: Posts: Comments:
669. BahaHurican
6:23 PM EDT on June 06, 2008
Evening all.

I see the CATL wave has taken centre stage . . . the fact that NHC has upgraded it to an area of interest at all suggests it's worth watching. It will be interesting to see how far it gets. I agree with those who suggest that short term conditions don't hold out much hope for the wave. However, if it holds together, we may get a burst of excitement 3 - 5 days down the road . . .
Member Since: October 25, 2005 Posts: 19 Comments: 21883
668. Smyrick145
10:19 PM GMT on June 06, 2008
Also any other thoughts other than Hurricane 23 are welcome.
Member Since: Posts: Comments:
667. Smyrick145
10:05 PM GMT on June 06, 2008
Hurricane 23,
I've been on this blog for the last couple years, I never post much but rest assure I check in 10 to 15 times a day. One thing I have always noticed about you is your conservative mannerism. However, lately I feel you have a true concern for the upcoming year. Am I over analzying this or could this be one hell of a year? P.S. I know most people don't buy into preseason hype, but we are almost in the middle of June now and we should start to see conditions setting up for the upcoming season. Any thoughts are very much appreciated.
Member Since: Posts: Comments:
666. STORMTTOP
10:08 PM GMT on June 06, 2008
we need a cat 8 in the GOM so the OIL/gas prices can go through the roof and kill us all already. You all will see the global collapse soon. Weather won't matter anymore.
Member Since: Posts: Comments:
665. Weather456
5:47 PM AST on June 06, 2008
The TUTT cells across the Caribbean and SW N ATL are helping to fuel daytime showers and thunderstorms over the Greater Antilles and Central America. LINK
Member Since: July 24, 2005 Posts: 407 Comments: 19076

Viewing: 714 - 664

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.