It’s New Year’s Eve Eve (sic sic). As European and American revelers-to-be make final preparations for celebration and jollity, southeast Asians struggle with life-threatening effects of the weather. Tropical storms, a powerful intertropical convergence zone, and an unusually potent monsoon are bringing multiple miseries to that part of the world.
The US is in the grip of the coldest arctic-air invasion of the year and getting colder, while on the other side of the Atlantic puddle, Europe will be warmer than normal.
Let’s go Around The World.
Focus On The Asian Tropics: Airliner Disappearance Likely Related To Weather
An airliner disappeared and is still missing. Now another temporarily disappears (as of this writing, a debris field has been found that is almost certainly from the missing jet) — but there was probably a much different cause.
AirAsia flight QZ8 501 was flying into bad weather when communications ceased after a request to change course. Parallels have been drawn between this disaster and the disappearance of MH370 last spring. However, this one appears to be weather related, and the plane is very likely at the bottom of the sea.
The intertropical convergence zone (ITCZ) is just what it sounds like: The flow of air from north of the equator meets the flow of air from south of the equator. The result is a zone of rising air and turbulent weather. Radar indicates that QZ5801 was heading into a very intense thunderstorm.
The pilot had radioed ground control requesting a change of altitude, but the storm was nearly 50,000 feet high, and the aircraft could not have flown over it.
Vertical currents in a thunderstorm can reach hurricane wind speeds. More important: the vertical winds can vary over small distances. This can create an imbalance between the lift on the wings and throw the plane into an unstable wobble. If the wobble becomes great enough, the pilot will lose control of the aircraft.
Focus On The Asian Tropics: An Unusually Vigorous Monsoon
The informal definition of a monsoon is a heavy rain associated with a seasonal shift in the wind. Usually we think of the monsoon as occurring on the Indian subcontinent.
However, the formal definition is as follows: A thermally-driven wind arising from differential heating between a land mass and the adjacent ocean that reverses its direction seasonally. Monsoons thus have two phases:
- In the summer, pressures fall over Asia and winds from the south bring monsoon rains to India.
- In the winter, strong high pressure develops over Asia; northeast winds bring moisture to Malaysia, Indonesia and southern Thailand.
This year the winter monsoon has been especially powerful and has caused severe flooding, accompanied by the loss of at least 24 lives.
Focus On The Asian Tropics: Tropical Cyclones In The West Pacific And Indian Oceans
Minimal Tropical Cyclone Jangmi has just exited the Philippines, and will cross the South China Sea, reaching the Malaysia, Thailand border next Sunday. Though it will contain tropical storm winds, the main effect will be to bring additional rain to the monsoon-soaked areas.
Tropical Cyclone Kate formed well west of Australia last week and meandered over the open ocean. The storm has now reached the equivalent of a category three hurricane with winds of 120 miles per hour, but will weaken and dissipate without threatening any land area.
Blast Of Arctic Air Invades The Central And Western US
For several weeks we have been talking about a new jet stream pattern. Instead of the blocking high pressure over the eastern Pacific which has dominated the past year, the flow brought storms to the west coast, including southern California. The jet stream has now reverted to its bad old ways of last winter and the past November: The Polar Vortex is pressing southward and allowing a straight shot of very cold air to envelop the US from the Great Basin to the Midwest. Later this week the frigid temperatures will reach all but the extreme southeast.
Unusual Snow In The Desert Southwest
Normally, with the jet stream pattern of high pressure over the west coast and low pressure over the middle of the country, waves ripple out of Canada and produce minor snowstorms known as Alberta Clippers. This time, a wave is amplifying over the Rockies and will spin out into a cutoff low over the extreme southwest. Cold air will penetrate into Arizona and southern California. High temperatures will run ten to twenty degrees below normal in Phoenix, Las Vegas, and even Los Angeles.
The result of all this will be an unusually low snow level, reaching elevations that normally don’t receive snow. Las Vegas could get several inches of snow on Wednesday and Thursday. This would be only the 16th time Las Vegas has gotten over an inch of snow in a single storm since record-keeping began in 1937. The normal annual snowfall is less than half an inch.
Europe Reverts To Warm Jet Stream Pattern
This week, Europe will see a return to last year’s pattern of above-average temperatures because the jet stream will be displaced to the north of its average position. Warmer than normal temperatures will cover the continent from Edinburgh to Berlin to Moscow. The only exception to the warmer than normal temperatures will be in northern portions of Scandinavia and Russia.
Ring In A Newer And Almost Certainly Hotter Year
As we wrap up the hottest year of combined land and sea temperatures on a worldwide basis since the beginning of the industrial revolution, the atmosphere is changing. After you recover from celebrating, look around and see what’s happening to the weather where you live.
Decoding Science. One article at a time.