Thirty Mile High Wave Encircling Earth to Break over North Pole on Christmas Day

An extraordinary atmospheric planetary wave (number 1), over thirty miles high, covering earth’s entire northern hemisphere, will break over the north pole on Christmas day. This wave, which will transfer tremendous amounts of heat to the upper stratosphere, is likely to split the polar vortex in two. This will likely drive cold air out of the Arctic towards the central and eastern U.S. in January and February.

The winter night that starts over the north pole in September causes a deep vortex to form around the north pole in early fall. By the 18th of December this year, the planet circling “storm in the stratosphere” was extraordinarily cold -115 ºF (-82 C) and winds today are as high as 220 mph (355 km/h) in the upper stratosphere where the atmospheric pressure is 1% of surface pressure (10mb). This monster storm that develops every fall above the weather layer has become more intense in the fall months with human caused global warming and ozone loss. This year has been no exception. However, as the polar vortex has become more intense in the fall it has also become more unstable in the winter months.

When the spin of the jet stream in the lower atmosphere (the troposphere) aligns with the spin in the polar vortex in the layer above, the stratosphere, as it does in the long polar winter, large amounts of wave energy may be transferred upwards. The most powerful wave is typically wave number 1 which encircles the northern hemisphere diving south over the Pacific ocean and pushing polewards over the Atlantic. When this wave intensifies, it not only drives heat towards the pole on the Atlantic side, it also drives wave energy upwards from the troposphere to the upper stratosphere. This upwards wave breaks at the boundary of the stratosphere with layer above it, the mesosphere. These upwards breaking waves generate large amounts of heat and put a brake on the winds at the top of the stratosphere.

The dome of heated air that is formed spins clockwise, like a surface high pressure area, and disrupts the westerly flow of the storm-like vortex below it. The slowing and heating of the polar vortex in the upper stratosphere works its way to lower levels by this process of vortex disruption. In strong stratospheric warming events the vortex disruption may work its way down to affect polar surface weather over the winter months. Strong events usually happen in January and February. The period around Christmas is very early for a major stratospheric warming, but both the American and European models now predict it will happen. The models indicate that there’s a good chance that the polar vortex will be split in two by the intense warming.

Judah Cohen@judah47

Latest GFS predicts #PolarVortex split early next year. Besides that I am fascinated with PV splits this could have important implications for the weather including a #colder Europe and heavier #snowfall for the Northeastern US but for now remains speculative!

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1:06 PM – Dec 18, 2018

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When the polar vortex disruption reaches the lower atmosphere it tends to increase the surface pressure over the north pole and Arctic ocean. In particular, the Beaufort high, that is located north of Alaska over the Beaufort sea, intensifies and the flow of cold air out of the Arctic east of the Rocky mountains intensifies. The flow of cold air towards western Europe may also intensify like it did late last winter when “the beast from the east” brought bitterly cold Siberian air to western Europe. This year, the American CFS model forecasts that the eastern U.S. will be colder than normal, but not western Europe.  It forecasts that a cold flow out of the north polar region will bring brutal cold to northern Siberia and Scandinavia in mid-January, but not western Europe. Time will tell. The model cannot be depended on to predict details accurately. What’s clear is that the eastern half of the U.S. is likely to be significantly colder than normal in mid-January. This forecast for mid January is consistent with what happened after major stratospheric warmings in El Niño years like this one.

The eastern U.S. is likely to be cold in mid-january while Alaska and western Canada is likely to be warm. There’s a good chance of wet weather in California this January because storms will likely move in below the blocking high pressure are that is likely to form over Alaska and the Yukon.

Climate change may be amplifying the impacts of El Niño events and major stratospheric warmings. Large areas of the Barents sea, which used to be covered by ice and a fresh water layer, is now an extension of the north Atlantic. This region can now transfer huge amounts of heat from the ocean to the atmosphere amplifying planetary wave number 1 near the pole. Likewise, the increase in ocean heat in the north Pacific, particularly in El Niño years, increases the amplitude of wave 1.  This may be destabilizing the polar vortex in mid-winter leading to more extreme weather and increased variability in winter weather.

Ocean heat in the subarctic seas, in areas formerly covered by sea ice, is adding energy to polar vortex disruptions.

There is a large area of open water on the Atlantic side of the Arctic where sea ice normally used to be found. The heat from open water in this region adds to the disruption of the polar vortex.

The good news in this combination of a sudden stratospheric warming and El Niño is that California is likely to have a wet January as the storm track gets pushed south by likely blocking high pressure areas over Alaska. This weather pattern could extend into February, but the model becomes less accurate over time. The impact of major stratospheric warmings can continue for several months while vortex disruptions work down “like dripping paint” from the stratosphere into the weather. The cold weather in the eastern U.S. and warm weather in Alaska will probably continue into February. California is likely to have a wetter than normal period from January through March.

California is likely to have a wet January.

The CFS model prediction of wet weather for California is consistent with similar situations but the prediction of a dry east coast is not consistent with the historic record. Historically, heavy snow events have happened on the east coast following sudden stratospheric warmings.  Cold air may dam up over eastern Canada and storms may track up the east coast delivering large amounts of snow to the mid Atlantic and northeast if this winter follows historic patterns. Time will tell.

California is likely to have a wetter than normal period from January through March.

Watch out Santa. Climate change is warming the north pole and sending its cold air to us.

Update 20Dec18 9amEST

Both the European and American models are forecasting the stratospheric polar vortex will split. The most recent analysis map for the upper stratosphere at 10mb shows that the stratospheric warming has begun over northern China and Mongolia. The European model predicts that this warming will split the vortex in two over a period of ten days.

The European (ECMWF) model forecasts  the splitting of the stratospheric polar vortex in two in ten days on 29Dec18. This disruption will likely slowly work its way down in the atmosphere to impact weather in north America by mid January. The eastern half of the U.S. is likely to have a cold winter.