Weather Around The World, 11/18: Arctic Choke And A Tropical Cyclone

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Home / Weather Around The World, 11/18: Arctic Choke And A Tropical Cyclone
The jet stream forecast for Thursday shows the polar vortex remaining over central Canada and the central and eastern US. Forecast courtesy of NOAA

The jet stream forecast for Thursday shows the polar vortex remaining over central Canada and the central and eastern US. Forecast courtesy of NOAA

The big news in the States is the continued brutally cold weather in the eastern two-thirds of the country. With the cold air in place, any attempt by warmer flows to reclaim territory is shunted aloft by the denser arctic invader.

The result is widespread, though relatively light, rain and snow — except in the lee of the Great Lakes, where locally several feet of snow can accumulate.

The newest tropical cyclone is far from US shores. In fact it’s on the other half of the globe. There are no dull moments weatherwise this week, so let’s go Around The World.

Extreme Weather Event Artichoke Still Going Strong

A week of unseasonable and unreasonable cold continues. An end is in sight, but not for several more days. Artichoke has been remarkably widespread and long-lasting. Here are just a few examples:

  • Low temperature records were broken in at least 20 states last night.
  • Many cities have experienced their longest period of below-freezing temperatures.
  • Tornadoes up to EF-2 intensity roared across the deep south.
  • Two feet of snow has fallen in the lee of Lakes Erie and Ontario, and it’s still coming down.
  • Santa Ana winds up to 50 miles per hour are whistling through the mountain passes of southern California.

As the polar vortex whirls around in central and eastern Canada, fresh pulses of arctic air tumble southward out of the Yukon. As long as the deep low over the Aleutians and the omega block in the eastern Pacific persist, there will be little change in the pattern and no letup of the cold temperatures.

Perfect Setup For The Great Lakes Snow Machine

With the next push of cold air coming in behind what the Weather Channel has mistakenly called Winter Storm Bozeman (just a minor wave in the jet stream), the wind will turn west over Lakes Erie and Ontario. The long fetch across the lakes puts Buffalo and Watertown, New York in the bull’s-eyes for very heavy snow. The wind simply scoops the water off the lake and dumps it in the form of snow on the nearest shore. Up to three feet is expected right along the lakefront.

Normally an air temperature fifteen degrees below the water temperature will create lake-effect snow. This time, with the air so cold and the water still very warm, the contrast will be more than thirty degrees. Combine that with a west wind blowing over the entire expanse of Lakes Ontario and Erie and — the better to bury you in snow, my dear.

A Tropical Cyclone On The Other Side Of The World

There is no activity in the tropical North Atlantic or North Pacific worth talking about. But that doesn’t mean that tropical cyclone season is over. In fact, it never ends. After all, it’s always summer or fall somewhere.

Cyclone season in the South Indian Ocean officially runs from July 1 to June 30. However, cyclones before December are rare. Yet now we have one, so maybe this will be a busy season there, as it was in the tropical North Pacific during the recent northern hemisphere summer.

South Indian ocean cyclones typically impact the island country of Madagascar and the adjacent African mainland country of Mozambique, or blow themselves out over the ocean.

Tropical Cyclone Adjali

Tropical Cyclone Adjali is in the center of the Indian Ocean. Forecast courtesy of US Navy

Tropical Cyclone Adjali is in the center of the Indian Ocean. Forecast courtesy of US Navy

A weak tropical low pressure system meandered through the middle of the Indian Ocean last week, but yesterday become organized into Tropical Cyclone Adjali.

Decoded Science will accept the name and the designation of tropical cyclone, but will refer to its strength in terms of an equivalent hurricane category.

Adjali is now a strong Tropical Storm, and could become a category one hurricane today or tomorrow before petering out short of landfall. It could disrupt the ongoing search for missing airliner MH370 by producing high waves in the search area west of Perth, Australia, but otherwise it will have little impact.

The California Santa Ana

The blocking pattern of low pressure over western Alaska and high pressure over the eastern Pacific can produce a northeast wind in southern California. When the wind blows down from the Sierras through the mountain passes, ti is squeezed into narrower canyons and accelerates.

The resulting warm, dry wind is called Santa Ana. The current event, broadly associated with Artichoke,, is relatively mild, with winds topping out under 50 miles per hour (they can reach hurricane force in an extreme event).

Since the air will have lost its moisture in the mountains, the Santa Ana is very dry and exacerbates fire danger. The danger has been elevated the past few days, but will drop by tomorrow.

US – China Agreement On Global Warming

Though the agreement between Presidents Obama and Xi represent a step forward in the battle against climate change, at the same summit the Chinese agreed to help Pakistan produce coal and use it for the generation of power.

The temperature forecast for days three through seven (Thursday through Monday) shows a strong warming trend. Forecast courtesy of NOAA

The temperature forecast for days three through seven (Thursday through Monday) shows a strong warming trend. Forecast courtesy of NOAA

The two major polluters must rein in and ultimately drastically cut their production of greenhouse gases of course; but developing nations in Asia and Africa will put increasing pressure on the developed nations to make further cuts in emissions.

Scientists warn that time is running out for the citizens of Earth to keep global climate change from becoming irreversible. Will the China – US agreement be too little, too late?

When Will It Warm Up?

A pronounced warming trend will take place by the coming weekend, with temperatures in much of the eastern US returning to normal or even above normal.

A strong ripple in the jet stream will break down the omega blocking high on the west coast. This will push the polar vortex back north.

When this has happened in the past year, the dominant pattern has quickly become reestablished. Decoded Science is expecting that to happen again.

Overall, the earth is warming and weather is becoming more extreme — both warm and cold. A careful observer can see the changes. What’s happening where you are?

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