Warming Arctic May Be Causing Jet Stream To Lose Its Way

[jakeXT]

...

In all of the talk recently about the "polar vortex," you've already heard some of this. But as Wired UK explains:

"The strength of the jet stream is directly proportional to the difference in temperature between the poles and the tropics. When it's strong, the jet stream tends to take a straighter path, but when it's weak it meanders. As the Arctic is experiencing warming at faster rates than the tropics, that difference is getting smaller, so the jet stream is weakening along with it.

"What that means for mid-latitudes, where Britain [and the U.S. are] located, is weather that stays in place for longer. Weather patterns will be more likely to get 'stuck' over a location, yielding long periods of rain and sun rather than Britain's traditional 'changeable' skies."

"The temperature difference between the Arctic and lower latitudes is one of the main sources of fuel for the jet stream; it's what drives the winds. And because the Arctic is warming so fast, that temperature difference is getting smaller, and so the fuel for the jet stream is getting weaker," Francis says. "When it gets into this pattern, those big waves tend to stay in the same place for some time. The pattern we've seen in December and January has been one of these very wavy patterns.

"It doesn't mean that every year the U.K. is going to be in a stormy pattern," she adds. "Next year you could have very dry conditions, and for that to be persistent. You can't say that flooding is going to happen more often. Next year may be dry, but whatever you get is going to last longer."

http://www.npr.org/blogs/thetwo-way/2014/02/16/277911739/warming-arctic-may-be-causing-jet-stream-to-lose-its-way

[RobertEarl]

1. Sounds a little windy to me

What we do see is that the gulf stream is now flowing past N. Europe into the arctic circle all the way to Siberia.

Siberia is warmer than ever. Duh! As the gulf stream flows past England, it is bringing with it warm air that is colliding with the cold air from the arctic and that is causing severe weather.

In the Pacific a huge ball of 4+ degree warmer than usual water is causing the air above it to circulate in an expanding motion and we all know that expanding air turns right. As it turns right it pushes warm air into Alaska and into the Arctic. The normally cold air in the Arctic is being pushed out and since it has hit the Siberian warm air on the other side of earth, it has nowhere to go but down over Canada and into the US, mainly on the east coast.

See this linked page for evidence of the warmer than usual water masses on each side of the US.

http://weather.unisys.com/surface/sfc_daily.php?plot=ssa&inv=0&t=cur

[truedelphi]

4. Thanks for this input.

What has been totally different this year, for those of us living in California and Oregon and to some extent even state of Washington, is that the wind is now quite often from the South East.

I am no talking about it being from the South East for a day or two, but entire bands of time.

The area the wind is coming from seems to be outside Reno Nevada. Consequently it seems to be the pressure front created by the continual wind from Reno going northwest that pushes the rain that should be coming from Alaska and Canada down onto WA OR, and Calif instead into the area of Idaho Utah etc.

Here is the wind map:

http://hint.fm/wind

On edit, for the past two weeks, we have had a slightly more normal wind pattern. And even some rain! Although one meteorologist says the way to think of our drought is to imagine eight ounces of liquid in a five gallon bucket.

[RobertEarl]

5. That makes sense

The fact that the PNW was getting a SE flow which is pretty much just a localized wind. Taken in the CONUS - CONtinental US - context, the high pressure surface winds coming down from Canada over the Midwest CONUS would cause the SE wind into the PNW.

Highs turn to the right, or clockwise. So picture the CONUS with a High over the Midwest between the Atlantic and the Pacific, and you will see how the SE wind would occur.

Now your surface winds are coming from the west. In the west is that high over the pacific which has backed away from the coast a bit allowing colder air to come down from Alaska. That cold air is mixing with the warm pacific air and when that happens precipitation begins. The Pineapple express is formed from a high over the equatorial pacific that is due south of California blowing winds up and into that colder Alaskan air.

Most wet winter weather is weather that runs along the outer edges of the high pressure systems. The recent snows along the east coast were from lows running along the outer edges of the Atlantic highs and the Midwest highs. The recent wet weather in the west is running between the two highs over the pacific.

[HereSince1628]

2. There is a youtube of a scientific presentation that suggests varying altitude of the polar cell

(that is a consequence of arctic warming) facilitates the northern jet to wander from in it's position (typically) between the Polar and Ferrel cell and contribute to these 'kinks' which not only tend to persist in one area for 60-ish days, but apparently can endure to make an entire circuit around the hemisphere at known speed thereby...contributing to long term forecasts.

I'm not a weather scientist myself and I can't speak to that being an accepted explanation, I'd actually like to know if anyone knows if it is....I wish I could find it again...a quick search didn't find it...

Long ago, in a different century even (!), I was taught that the "tumbling" of these latitudinal bands of atmosphere is what transports the heat from the equator to the pole.

[truedelphi]

3. In a computer modelling of what would happen should the jet stream slow due to Global

Warming and then totally stagnate, *** these were the conclusions:

One) First the jet stream would slow

Two) Finally the jet stream would stall. As it stalled entirely, whatever weather was going on inside any particular area would continue. Viruses and bacteria would proliferate, as it is the jet stream that helps keep such material on the move, diluted and swept away. But without the jet stream moving, humans and animals would fall ill to various plagues and be wiped out. Eventually the planet would be a lifeless planet, at least in terms of flora and fauna of any significant size.

This was research I duly printed out, saved and utilized for a sci fi story I was writing. I have long since lost the original data, and can't remember the names of the grad students who put it together. But the whole idea of the jet stream slowing is very scarey.

*** Study was done way back in the mid seventies (when the fear was that humanity and Planet Earth were headed into another Ice Age.)

[benld74]

6. I would think THIS would somehow create the polar vortexes?