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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613. SpaceThrilla1207
6:13 PM GMT on June 06, 2008
I don't really trust the CIMSS wind shear map anymore...they always overhype the shear...I've seen some BS shear ratings with that map. Not messing with it anymore as of june '07.

This is the shear map I trust.

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612. StormJunkie
6:13 PM GMT on June 06, 2008
608.

According to the GFS and CMC it is.

Model Learning Videos
Member Since: August 17, 2005 Posts: 26 Comments: 16874
611. pottery
2:10 PM AST on June 06, 2008
Hi, all.
Been out all day, now looking at the wave at 55w.
Looking good for rain and squally conditions tonight and Saturday
. Not a sign of that now though. Hot, dry, dusty. Enter 'piarco' in the "check weather" box to monitor Trinidad weather as this system goes through.
Member Since: October 24, 2005 Posts: 0 Comments: 24882
609. Weather456
2:12 PM AST on June 06, 2008
603. SpaceThrilla1207 2:09 PM AST on June 06, 2008
Besides the 20-25 knot shear, what else is wrong for you guys to count out development with this system?


in addition to what sj pointed out...the shear in the Caribbean.

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608. SpaceThrilla1207
6:11 PM GMT on June 06, 2008
Upper-level lows don't develop into tropical depressions, groundswell...needs a closed surface low, not upper-level.


StormJunkie, it's not going to hit south america.
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607. cchsweatherman
2:10 PM EDT on June 06, 2008
603. SpaceThrilla1207 2:09 PM EDT on June 06, 2008
Besides the 20-25 knot shear, what else is wrong for you guys to count out development with this system?


Shear will continue increasing as it moves towards the WNW. In about 24 hours, it will enter 40kt. shear. This is the reason for us counting out development, although a weak TD could be possible.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
606. Drakoen
6:10 PM GMT on June 06, 2008
603. SpaceThrilla1207 6:09 PM GMT on June 06, 2008
Besides the 20-25 knot shear, what else is wrong for you guys to count out development with this system?


That type of wind shear is high enough already and its moving into an area of even higher wind shear. That's the main inhibitor. Everything else as far as SST'S and low level cyclonic turning is there also the environment has gradually become more moist.
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605. groundswell
6:08 PM GMT on June 06, 2008
That upper low is headed due west-with a surface trough-water temps & shear are marginally ok, but does this have a chance to slowly develop? Wouldn't Florida get at least some much needed rain?
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604. StormJunkie
6:10 PM GMT on June 06, 2008
603.

South America...Stage left...
Member Since: August 17, 2005 Posts: 26 Comments: 16874
603. SpaceThrilla1207
6:08 PM GMT on June 06, 2008
Besides the 20-25 knot shear, what else is wrong for you guys to count out development with this system?
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602. Drakoen
6:07 PM GMT on June 06, 2008
600. Floodman 6:05 PM GMT on June 06, 2008
Thanks, StormW, Drak, Hurricane23 and 456...not to mention CCHS...you guys are always right there with some good analysis, and even your arguments are educational for those of us who are learning...


There's no argument here although I did feel a little hostility at first.
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601. CaneAddict
5:59 PM GMT on June 06, 2008
Im sure this area east of the Antilles will be tagged Invest 91L....after seeing it listed as an area with potential for development.
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600. Floodman
5:55 PM GMT on June 06, 2008
Thanks, StormW, Drak, Hurricane23 and 456...not to mention CCHS...you guys are always right there with some good analysis, and even your arguments are educational for those of us who are learning...
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599. Weather456
2:00 PM AST on June 06, 2008
598. Drakoen 1:59 PM AST on June 06, 2008

ok
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598. Drakoen
5:57 PM GMT on June 06, 2008
589. Weather456 5:49 PM GMT on June 06, 2008
Drak, I looked at these two charts also WV Imagery and the upper flow is easterly around the based of the upper high over the Deep South and westerly from the West Gulf across the Yucatan into the Caribbean. This created a confluent pattern across the Eastern Gulf between these two opposing flows. Subidence results and thats my reasoning.


I think the confluence you are seeing is associated with the upper level low over the Bay of Campeche. I see upper level divergence aloft around the low which is typically associated with upper level diffluence.
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597. txalwaysprepared
5:56 PM GMT on June 06, 2008
Houstonian - same here! 5 whole minutes!
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596. SpaceThrilla1207
5:49 PM GMT on June 06, 2008
http://www.nhc.noaa.gov/

20% chance of 48-hr development into a TD.

shear

Although with the borderline hostile shear environment, the other factors have to be in place and real good for it. Keep in mind other tropical storms HAVE formed around this time under heavier shear (ie Barry)

dry air

Dry air doesn't look too bad, not nearly as bad as a couple days ago.

Ssts

Water temperatures look pretty good, around 28-29 degrees. Definately warm enough for development. Keep in mind that the water and TCHP will only get warmer as this moves westward.
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594. NEwxguy
5:49 PM GMT on June 06, 2008
23,thanks,thats a good piece about steering currents.It seems every year predictions are made as to how highs and troughs are going to set up,but as been proven,its very hard to see a month or more ahead.Troughs have been protecting us up here in the northeast,but some think not this year.
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593. guygee
5:33 PM GMT on June 06, 2008
Re: 574
Bull$%^@!

You should be replying to the scientific merits of the article that Dr. Masters discussed.

I'm not sure what is worse, your complete denial and refusal to even look at the science, or 84. pearlandaggie's totally bogus psuedo-science links that nobody here has bothered to challenge (anybody want to tell me why Joe D'Aleo uses the USHCNV2 temperature data set? What is Dr. Bruce J. West's real field of expertise? Does he really speak for the United States Army on matters of climate and related future policy? Why shouldn't we use linear regression analysis on correlated skewed data? What is the difference between weather and climate? Does AGW preclude natural climate variability?...etc, etc.)

Either nobody here even knows, or nobody cares, including Dr. Jeff. Pretty pathetic.

Later!

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592. weatherblog
5:45 PM GMT on June 06, 2008
I don't remember watching waves this frequent last year (or any year at all) until at least July.
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591. Weather456
1:49 PM AST on June 06, 2008
586. cchsweatherman 1:47 PM AST on June 06, 2008
For Drak and 456 - Here is what the NHC has to say regarding your debate between whether there is upper confluence and upper diffluence.


We are talking about the Gulf not the SW Caribbean, I already stated that in my update.

Diffluent flow associated with an upper trough and a series of embedded TUTT cells that digs into the Caribbean is helping to fueling scattered showers and thunderstorms over Central America and the SW Caribbean. This activity is aided by low level lift induced by a passing tropical wave along 79W and the Colombian Low.
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589. Weather456
1:45 PM AST on June 06, 2008
Drak, I looked at these two charts also WV Imagery and the upper flow is easterly around the based of the upper high over the Deep South and westerly from the West Gulf across the Yucatan into the Caribbean. This created a confluent pattern across the Eastern Gulf between these two opposing flows. Subidence results and thats my reasoning.

LINK

LINK
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588. hurricane23
1:47 PM EDT on June 06, 2008
Little moisture is expected for southeast florida dade/broward as high pressure is not going anywere anytime soon. Tropical moisture unfortunatly will stay to our south.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
586. cchsweatherman
1:44 PM EDT on June 06, 2008
For Drak and 456 - Here is what the NHC has to say regarding your debate between whether there is upper confluence and upper diffluence.

HIGH PRESSURE IN THE W ATLC IS MAINTAINING STRONG EASTERLY
TRADES ACROSS THE CARIBBEAN. AN UPPER DIFFLUENT PATTERN OVER THE
SW CARIBBEAN IS GENERATING NUMEROUS SHOWERS AND THUNDERSTORMS S
OF 14N W OF 75W.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
585. stormdude77
1:45 PM AST on June 06, 2008
Given the Twave was in the TWO, I'm surprised it wasn't posted 5-10 times, LOL...
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584. StormJunkie
5:24 PM GMT on June 06, 2008
Thanks cchs and 456. Hopefully it will stir up a little moisture for the SE and Fla especially.

Interesting analysis SW. Will be interesting to see how the season plays out.
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583. hurricane23
1:42 PM EDT on June 06, 2008
No surprise as 40-50kt windshear is blowing through the caribbean.Interesting though to see that wave push west which come august the result might be different.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
582. txalwaysprepared
5:43 PM GMT on June 06, 2008
Hi All! I see a few familiar faces, but not too many. I'm sure I'll see more as the season goes on.

We need some rain here in SE TX!!
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581. hurricane23
1:37 PM EDT on June 06, 2008
With significant warming of sst's and below average wind shear across parts of the tropical atlantic as i stated yesterday is recipe iam not to interested in.

The warming across the eastern atlantic is really something to see.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
580. Patrap
12:39 PM CDT on June 06, 2008
ESL by LSU Link
Member Since: July 3, 2005 Posts: 428 Comments: 129841
579. Drakoen
5:37 PM GMT on June 06, 2008
575. Weather456 5:27 PM GMT on June 06, 2008
573. Drakoen 1:23 PM AST on June 06, 2008
W456, where are you getting upper level confluence from? The cimss shear map and 200mb streamline indicate that an upper level ridge, which extends outward from an upper anticyclone over western Mexico, is over the Gulf of Mexico; as well as a 200mb anticyclone over the eastern Gulf of Mexico is supporting a diffluent flow aloft.

That again...I see a confluent flow that supports dry air and u see a diffluent flow. I'm not debating that with you.


LOL ok. Can I at least get an explanation.
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578. weathermanwannabe
1:34 PM EDT on June 06, 2008
568. StormW 1:16 PM EDT on June 06, 2008

Thanks Storm; Gonna have to keep a very close eye on the "lowrider" waves this season....
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577. Drakoen
5:36 PM GMT on June 06, 2008
000
ABNT20 KNHC 061728
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI JUN 6 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A WESTWARD-MOVING TROPICAL WAVE IS APPROACHING THE WINDWARD ISLANDS.
UPPER-LEVEL WINDS ARE FORECAST TO REMAIN UNFAVORABLE FOR TROPICAL
CYCLONE DEVELOPMENT. HOWEVER...THIS SYSTEM COULD PRODUCE
SHOWERS...THUNDERSTORMS AND GUSTY WINDS OVER PORTIONS OF THE
WINDWARD ISLANDS LATER TODAY AND ON SATURDAY.

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.
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576. hurricane23
1:34 PM EDT on June 06, 2008
Hey SW!

Here is a bit on steering currents i wrote a few weeks back.

For those wondering about steering patterns for 2008 the important thing to watch for is what the conditions are that steer the storms when there is a storm in the area. Timing is critical. A pattern that would steer a Cape Verde Hurricane directly into Florida for example could exist for two months, but if there is no Hurricane to be steered the pattern is meaningless. Charley slammed into SW Florida because an early season trough just happened to be in the right place as Charley turned north in the Gulf. History shows most Tropical Cyclones that enter the Gulf pass west of the southwest coast of Florida and vent their fury from the Florida panhandle to Mexico. Last year we watched as two Cat 5 monsters traveled the whole length of the Caribbean but couldn't turn north because of the strong high pressure system to the north that happened to be in place at just the right time to protect Florida and the gulf coast. In 2004 and 2005 we watched as Charley, Dennis, Katrina, and Rita were able to get into the Gulf because they were not blocked. Regardless of how strong a Tropical Cyclone is, it always follows the path of least resistance. It's not "where" a Hurricane is, but "when".

Overall our atmosphere is just to complex and coupled to be able to determine what absolute locations will be impacted but, by using climatology and examining similar weather patterns in data, we can come to an educated conclusion of where the highest chance of seeing tropical cyclone activity could be.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
575. Weather456
1:25 PM AST on June 06, 2008
573. Drakoen 1:23 PM AST on June 06, 2008
W456, where are you getting upper level confluence from? The cimss shear map and 200mb streamline indicate that an upper level ridge, which extends outward from an upper anticyclone over western Mexico, is over the Gulf of Mexico; as well as a 200mb anticyclone over the eastern Gulf of Mexico is supporting a diffluent flow aloft.


That again...I see a confluent flow that supports dry air and u see a diffluent flow. I'm not debating that with you.
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573. Drakoen
5:14 PM GMT on June 06, 2008
W456, where are you getting upper level confluence from? The cimss shear map and 200mb streamline indicate that an upper level ridge, which extends outward from an upper anticyclone over western Mexico, is over the Gulf of Mexico; as well as a 200mb anticyclone over the eastern Gulf of Mexico is supporting a diffluent flow aloft.
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572. guygee
5:20 PM GMT on June 06, 2008
I love those CIMMS wind analysis maps...alway waiting for the next update! I keep consecutive copies to compare.
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571. cchsweatherman
1:16 PM EDT on June 06, 2008
Updated Steering Currents
Member Since: April 14, 2007 Posts: 8 Comments: 5169
570. Weather456
1:13 PM AST on June 06, 2008
566. StormJunkie 1:11 PM AST on June 06, 2008

I noted that last night but waited 12 more hours to be sure. Deep layer steering will move it towards the WNW around a deep layer ridge to its north and east. So what ur observing is correct.
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569. OSUWXGUY
5:14 PM GMT on June 06, 2008
Dry air evident in that convection with that tropical wave... Lots of outflow boundaries. Probably will weaken a bit more shortly than pulse up and down...
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567. cchsweatherman
1:14 PM EDT on June 06, 2008
That's correct StormJunkie. It will likely increase the rain chances for South Florida for early to middle part of next week. It will be interesting to see how much moisture it transports and to see if it gains any surface reflection.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
566. StormJunkie
5:08 PM GMT on June 06, 2008
Afternoon all :~)

That Twave is not really that impressive, but just my two cent....Not to mention it is about to plow in to Central America.

456-Since things are slow, learn me something.

This shows that ULL headed towards the E coast correct?
Member Since: August 17, 2005 Posts: 26 Comments: 16874
565. guygee
5:08 PM GMT on June 06, 2008
CATL wave looking more sheared today, also looking maybe like its going to scrape along South America...ouch!
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564. guygee
5:02 PM GMT on June 06, 2008
545. GainesvilleGator 4:46 PM GMT on June 06, 2008
The issue making the price of Crude go thru the roof isn't the fear of running out of it in 20 years it has to do with "Peak Oil" theory. This pretty much says that demand will be greater than supply at some point in the future. This will cause shortages which will lead to higher prices. Most information I have read says we have a greater than 50 year supply of crude.

Bottom line, we are not running out of crude anytime soon but supplies will be tight unless we find alternative resources.


Technically we will not run out of crude oil and its byproducts, but speaking in practical terms if you cannot afford to pay $5, $10, $15.../gal for gasoline, then your ability to pay has run out.
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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.

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