What we are seeing, here and now, is the transformation of the atmospheric physics of this planet.
This great dissolution, of ice and certainties, is happening so much faster than most climate scientists predicted...
The melting disperses another belief: that the temperate parts of the world – where most of the rich nations are located – will be hit last and least, while the poorer nations will be hit first and worst. New knowledge of the way in which the destruction of the Arctic sea ice affects northern Europe and North America suggests that this is no longer true. A paper published earlier this year in Geophysical Research Letters shows that Arctic warming is likely to be responsible for the extremes now hammering the once-temperate nations.
The north polar jet stream is an air current several hundred kilometres wide, travelling eastwards around the hemisphere. It functions as a barrier, separating the cold, wet weather to the north from the warmer, drier weather to the south. Many of the variations in our weather are caused by great travelling meanders – or Rossby waves – in the jet stream.
Arctic heating, the paper shows, both slows the Rossby waves and makes them steeper and wider. Instead of moving on rapidly, the weather gets stuck. Regions to the south of the stalled meander wait for weeks or months for rain; regions to the north (or underneath it) wait for weeks or months for a break from the rain. Instead of a benign succession of sunshine and showers, we get droughts or floods.
The warming of the Arctic appears to be changing the trajectory of the jet stream in certain seasons, leading to more persistent weather patterns. The solid line represents a typical jet stream trajectory, and the dashed line represents the expected northward elongation of the waves in the jet stream in response to Arctic warming. Image and description from Linking Weird Weather to Rapid Warming of the Arctic
The Florida Panhandle/Alabama flooding and the recent rash of tornadoes were caused by a Rossby wave blocking pattern. Connect the dots, folks, from Arctic melt to Florida flood.
To get five times the typical monthly rainfall in roughly 24 hours is mind-boggling.
The overall storm system was monstrous. A strongly pronounced kink in the jet stream has been effectively stuck in place for days, held fast by a sluggish dome of high pressure over Hudson Bay in Canada. As I wrote earlier this week, blocking patterns like this are known for their ability to create extreme weather.
This is the same weather pattern responsible for a rash of tornadoes since Sunday and heavy snow in the Dakotas. [emphasis mine]
New evidence of Rossby Waves creating extreme weather.
The study showed that larger waves can lead to droughts in central North America, Europe and central Asia, and western Asia exposed to prolonged wet spells. It also shows western North America and central Asia are more prone to heat waves, while eastern North America is more likely to experience prolonged outbreaks of cold.
... the weather extremes they examined were month-long heat waves, cold spells, droughts and prolonged wet periods, which occurred over large areas.
... "The study revealed that these types of events are strongly related to well-developed wave patterns, and that these patterns increase the chance of heat waves in western North America and central Asia, cold outbreaks in eastern North America, droughts in central North America, Europe and central Asia, and wet spells in western Asia. [emphasis mine]
This set of images nicely illustrates how a deeply curved jet stream can simultaneously bring 90°F weather to northern Canada and cold air to Minnesota.
The Jet stream has ruptured! The "refrigerator door" separating the Arctic is off the hinges, so to speak. Wind is blowing from Hawaii, up through the Bering Strait, right across the Arctic Ocean, and down into the Atlantic on the other side.
the Bering Strait and on over the polar zone.
The current pattern involves an extreme weakness and high amplitude wave in the Jet Stream extending from the Central Pacific and into the Arctic, extending well above the 80 degree North Latitude line. What remains of the cold air pool has been split, with some of the cold air mass shoved toward Greenland and the Canadian Archipelago and the remainder shoved toward the Kara Sea. Driving through it all is a wedge of warmer air accompanied with the southerly winds, winds that originated in the tropics near Hawaii.
This is an epic journey in defiance of typical and prevailing weather patterns spanning thousands of miles and three oceans. It is decidedly not normal. [emphasis mine]
So far 2014 has been a record year for weather extremes in the US, due to the Jet Stream being "locked". Normally a year is colder than average or warmer than average. This year we had both at once, as if the country were in two different climes.
... the [Jet] stream is locked in a “positive” phase, meaning it’s hauling warmth up to the West and then blasting the East with polar chill. As the climate continues to warm, these stream-derived temperature differences could become entrenched, the scientists say, with the West experiencing more “mild, relatively warm winters” and the East increasingly winding up underneath a “freight car of arctic air.”
Alaska's north slope could see 50° while Montana gets weather 50° colder than usual. Atlanta will be colder than Barrow!
The highly elongated jet stream, whose circuitous route right now bends from Siberia down toward Hawaii back to the Arctic north of Alaska and then straight south toward the Midwest and East Coast, is morphing into an “Omega Block,” named after the Greek letter of a similar shape.
... the temperature extremes this particular pattern will produce are nothing short of breathtaking. In Great Falls, Montana, Tuesday’s high temperature is expected to top out at ... nearly 50 degrees below normal. Meanwhile, Barrow, Alaska—the northernmost city in the United States—will spend most of the week some 20 degrees above normal, with highs of about 30.
Some parts of Alaska’s North Slope will be much warmer than Barrow, possibly even reaching the 50s. As the Arctic cold front continues its push toward the East Coast, for a few days late this week, it’ll be colder than that in places like Dallas, Atlanta, and Washington, D.C. [emphasis mine]
With Inhofe in charge of US climate legislation, how much more could the Jet stream bend in the next four years? As if this weather were not surreal enough.
Temperature departure from normal in the Arctic for this time of year is astonishing.
Another positive feedback has been quantified, that accelerates Arctic warming.
By now you're aware that Rossby waves are deeper due to Arctic sea ice melt and Arctic warming, pulling cold air down into the US midwest and warm air up from Hawaii into the Arctic. This Hawaiian air "adds an extra heating to the Arctic air column equivalent to about 60% of the direct surface heat release from the sea-ice reduction."
The results from the simulation reveal that the recent Arctic sea-ice reduction results in cold winters in mid-latitude continental regions, which are linked to an anomalous circulation pattern similar to the negative phase of AO/NAO with an increased frequency of large negative AO events by a factor of over two. Associated with this negative AO/NAO phase, cold air advection from the Arctic to the mid-latitudes increases. We found that the stationary Rossby wave response to the sea-ice reduction in the Barents Sea region induces this anomalous circulation. We also found a positive feedback mechanism resulting from the anomalous meridional circulation that cools the mid-latitudes and warms the Arctic, which adds an extra heating to the Arctic air column equivalent to about 60% of the direct surface heat release from the sea-ice reduction. The results from this high-top model experiment also suggested a critical role of the stratosphere in deepening the tropospheric annular mode and modulation of the NAO in mid to late winter through stratosphere-troposphere coupling.
Pacific Typhoons make the jet stream go crazy, another Climate Destabilization feedback. I was astonished to see the Jet Stream split, merging with the Subtropical Jet Stream to the south and simultaneously flow over the North Pole.
"May You Live in Interesting Times," indeed.
Recent Typhoons Noul and Dolphin did this to the Jet Stream.
Furthermore, global warming is directly changing the path followed by the North Polar Jet Stream, from a relatively straight path at a latitude of 60°N to a wildly meandering path that at some places merges with the Subtropical Jet Stream and reaching speeds as high as 267 km/h (166 mph) and that at other places moves high into the Arctic and reaches speeds as high as 170 km/h (106 mph).
On above image, part of the jet stream even moves right across the pole. Such changes to the jet stream constitute one out of numerous feedbacks of global warming,...
... Alaska faces temperatures as high as 31°C (87.8°F), as illustrated by the image below. [emphasis mine]
The Jet Stream is forecast to loop up into the Arctic Ocean from Russia this week, bringing warm air to melt snow on land and sea ice. Substantial snow melt is anticipated.
Note the blue disappearing over large areas of the currently frozen Arctic Ocean. Early snow melt creates ponds on the ice which absorb more heat.
When Jet Stream waves bring warmth to the Arctic at this time of year, it initiates a feedback.
... more sea ice melt results in higher amplitude wave formation in the Jet Stream. Higher amplitude wave formation in the Jet Stream transports more warmth to the Arctic environment, resulting in more sea ice and snow melt which in turn weakens the Jet Stream further.
Omega Block: a stalled Rossby wave crest (that causes extreme weather). Don't be confused by the different names.
Extended hot dry weather set Fort McMurray up for the worst wildfire disaster in Alberta's history. High jet stream crests "get stuck", sending warm air north.
... the resulting jet stream configuration takes on the likeness of the Greek letter omega. In this case, cool and unsettled weather is affecting the eastern Pacific Ocean and eastern North America, including much of the U.S. East Coast. [emphasis mine]
When an Omega Block sits on Greenland, it's often called a Greenland Block.
... it is only May — not July when such extreme fire weather would typically be possible.
...given the fact that it will grow still hotter and drier in the months ahead, it looks like Fort McMurray — a city in the grips of the hard climate consequences it helped to create — is in for a long, rough fight.