In a busy week for weather news, the Obama administration rejected the Keystone pipeline; the World Bank issued an economic warning on warming; a second cyclone in two weeks is hitting Yemen; Tropical Storm Kate formed in the Atlantic; severe weather could affect the US; and the stage is set for COP21, the climate talks in Paris.
Let’s go Around The World.
Strong Thunderstorms Could Hit The Central US On Wednesday
The seasonal stability see-saw normally swings to the stable side in the fall, but strong thunderstorms can form any time a flow from the Gulf of Mexico interacts with a trough (dip) in the jet stream. The stage could be set for some wild weather this week.
The atmosphere does not respond the same at all levels to changes in daytime heating that are a result of the sun’s travels from tropic to tropic — or more precisely, due to the change in angle of the sun’s rays with season as the tilted earth travels in its path around the sun. Only a small amount of the sun’s radiation goes directly into the atmosphere; most of it heats the earth, which heats the air above. The warmth takes some time to work its way up to jet stream level.
Warm air rises. When the lower atmosphere is warm enough relative to the air at higher levels, columns of rising air can produce violent storms. In the spring, as the sun rises higher in the sky, the lower atmosphere warms faster than the air above, and the chance for instability increases. Things reverse in the fall.
This week a strong trough in the jet stream will produce low pressure moving through the Great Lakes. Severe weather is expected in a large area Wednesday, centered on Missouri.
Megh Update: Second Tropical Cyclone In November Makes Landfall In Yemen
No tropical cyclone with tropical storm force winds of 39 miles per hour or greater had ever made landfall in Yemen until last week.
Chapala made a grand entrance at 100 miles per hour, and now Megh follows with a 50 mile-per-hour encore.
By the time the two storms take their bows, the combined rainfall will leave the desert wetter than it’s ever been.
Surprise! Atlantic Tropical Storm Season Not Over: Kate Forms Over Bahamas
Just when Decoded Science thought the tropical storm season would end with ten named storms, an eleventh sneaks in, and though it will impact the same area hit by Joaquin last month, this one is much weaker.
The only real significance of Kate is that it brings the season up to average for named storms (Eleven is the average from 1966 to 2009; using a longer period, the average is twelve, but some of the old observations are questionable).
Decoded Science was the only predictor to forecast a normal season. Our bow will be modest, however, because the number of hurricanes and major hurricanes was below normal.
Kate could become the season’s fourth hurricane (normal is six) at its most muscular point, well off in the Atlantic, before being absorbed by a mid-latitude system and transitioning to an extra-tropical storm which could traverse the ocean and end up in the United Kingdom late in the week.
Obama Vetoes Keystone Pipeline
The Obama Administration, more for political than environmental reasons, will turn down the application of TransCanada Keystone Pipeline, L.P. to run an oil pipeline through the US from Canada to the Gulf coast. As the president explained, a decision to allow the construction of this pipeline would undermine the leadership of the US at the upcoming climate summit in Paris (COP21).
Environmentalists have pointed to the possibility of spills and the fact that the pipeline would bring a heavy type of crude oil to the market. Refining and burning of this kind of oil produces more greenhouse gases than the same processes for lighter crude of US origin. On the other hand, this oil is likely to get to market anyway, probably via rail, which is more environmentally unfriendly in that it burns more fossil fuels in the transportation, and the chance of a spill is greater than with a pipeline.
However, the president is correct: Approving the pipeline a month before the conference would send the wrong signal. It remains to be seen how the US follows up on its claim to ‘leadership.’
The US has been anything but a leader in the past, refusing to sign the Kyoto Protocol and continuing to be one of the world’s largest polluters:
- The US refused to sign the 1997 Kyoto Protocol, which is the legal basis for ongoing attempts to curb global greenhouse emissions. To be fair, Kyoto was weak and the US has made reductions in emissions on its own initiative. COP21 needs to come up with binding mechanisms to require and enforce reductions.
- In 2008, the US was responsible for 19% of the world’s greenhouse gas emissions; by 2013, the US emissions had fallen to just over 15% of the world’s total.
- In 2008, the US was second to Canada among the ten largest polluters in per capita emissions. By 2013, the US had passed Canada and was the leader in per capita emissions among the ten largest polluters.
Active Jet Stream Relaxes Its Grip By The End Of The Week
Though these are anecdotal observations, not based on rigorous science, the rapidly warming Arctic appears to be having the following effects.
- The northern boundary of the most active portion of the jet stream is being nudged south of its normal position.
- The southern boundary of the jet stream is trying to hold its ground.
- The result is a modest tightening of the pressure gradient, so that the jet stream is sometimes unusually vigorous. Residents of the midwest and northeast will attest to the fact that recent winters have been very active, weatherwise.
- The jet stream folds up into immovable eddies more frequently. The stagnant weather patterns that result lead to heat waves and flooding in summer, snowstorms and record cold in winter — and droughts at any season.
These are just casual observations of a number of meteorologists. But it is certain that the differential warming between the pole and lower latitudes will lead to changes in heat transport, and therefore in weather patterns.
There is evidence from 12,000 years ago, during a cold period called the Younger Dryas, that melting polar ice had a marked and sudden feedback effect by disrupting ocean currents. The theory of how that happened is based on the fact that melting glaciers are fresh water, which is lighter than salt water and this would produce a cold sea surface layer. It is not yet clear what feedback mechanisms could accompany the current warming on a worldwide scale, though acceleration of the warming of the poles (Polar Amplification) is now obvious.
The jet stream currently is active with a pronounced trough entering the Great Lakes; a deep surface low will form under the trough, causing thunderstorms and heavy rain south and east of the center, along with snow, wind and cold north and west of the center.
By the end of the week, forecasts call for the jet stream to relax, so seasonal weather can be expected for the important Big Ten football games on Saturday.
World Bank Says Global Warming Will Increase Poverty
With the UN climate conference (COP21) less than three weeks away, it seems like everyone wants to weigh in on climate change. The World Bank, in a study released Sunday, says the world’s extremely poor will increase by 100,000,000 by 2030 if drastic steps are not taken to stem the tide of increasing atmospheric greenhouse gases. Since many people vote on the basis of the fullness of their wallets, economic reports like the World Bank’s may move politicians to action where scientists’ warnings could not.
More Anticipation Than Usual Concerning The Weather
Will El Niño produce the expected winter rains in the parched west? (Many hoping it will.) Will the Polar Vortex revisit the eastern US? (Many hoping it won’t.) What about Australia’s drought, also El Niño-related? And we haven’t even gotten to Europe, where all eyes will be on Paris and COP21. What’s up with the weather where you live?
Decoding Science. One article at a time.