Grab
Your Ear Muffs, the New Year’s Arriving With a Frigid Bang
by Brian K Sullivan
30 december 2016
00:56 CET
Warmer Arctic
weather will spur a very chilly start to 2017
Climate change and
El Nino are behind shrinking polar sea ice
A deep freeze is
about to descend on North America, Europe and Asia thanks to record
high temperatures across the Arctic.
How’s that? “Think
of it like a seesaw,” said Matt Rogers, president of Commodity
Weather Group LLC in Bethesda, Maryland. If winter temperatures rise
north of Alaska, that “forces an equal-opposite downward-southward
push. The cold essentially has to go somewhere else.”
Meteorologists
theorize the phenomenon works this way: Warmth in the northern polar
region helps lock in jet-stream kinks that drag cold air south and
sets up conditions that weaken the polar vortex, the pressure zone
that usually traps the chill in the northernmost part of Earth.
Frigid thermometer readings are, as a result, delivered to the
Northern Hemisphere. So, warm Arctic, cold continents.
Forecasts show how
drastic it could be. For example, Chicago’s high on Monday is
expected to be 43 degrees Fahrenheit (about 6 Celsius) and its low
33, according to MDA Weather Services in Gaithersburg, Maryland. By
Friday, the high is predicted to be 18 and the low just 5.
Climate change and
the recently ended El Nino conspired over the last three years to
heat the planet to record levels. The ice cap dwindled. In September
it was the smallest in scope since 2007; its winter growth has been
the slowest in chronicled history.
6-10 day outlook
temperature probability.Source: National Oceanic Atmospheric
Administration
Sea ice keeps the
air above it cold, and in November in the Arctic it hit a record low,
according to the National Oceanic and Atmospheric Administration. For
several weeks, as as consequence, a large part of the Arctic has been
hotter than normal.
“We have a buoy
north of Alaska that went over to freezing around the 10th of
December, which is about a month later than it normally happens,”
said Jim Overland, a research oceanographer at the U.S. Pacific
Marine Environment Laboratory in Seattle, who made his first trips to
Arctic ice in the 60s.
Santa’s Surfboard
Because there is
less ice covering the Arctic Ocean, more of it has been exposed to
sunlight during the summer. Open water stores heat that lingers on
into the fall and early winter even after the sun has set for the
year.
Before Christmas
things looked so dire meteorologists wondered whether “Santa was
going to have to trade in his sleigh for a surf board,” said Judah
Cohen, director of seasonal forecasting at Atmospheric and
Environmental Research, a unit of Verisk Analytics Inc.
There have already
been spates of severely cold weather across Siberia and North
America, and what scientists call climate variability. National
Weather Service meteorologists in Dallas said temperatures have been
riding a roller coaster: On Dec. 18, the high at Dallas-Fort Worth
International Airport was 30 degrees; on Dec. 25 a record high of 80
was registered; on Wednesday another all-time high of 83 was set.
For a look at how
the Arctic chill is spurring a natural-gas rally, click here
While the U.S. and
Canada could get hit with brutal cold, Russia will probably bear the
brunt on the other side of the globe, said Bob Smerbeck, a senior
meteorologist with AccuWeather Inc. in State College, Pennsylvania.
Some chilly readings could brush Eastern Europe and seep into eastern
Asia.
There isn’t a
consensus on how the Arctic contributes to cold surges across the
hemisphere, and some scientists aren’t ready to believe the polar
region has much influence at all, Cohen and Overland said. At the
moment it’s not a widely studied meteorological field.
There’s no dispute
that one of the mechanisms that pump cold air south are kinks or
waves in the jet stream. Overland said the lack of Arctic-sea ice
seems to lock these kinks in place for weeks at a time. In addition,
the high pressure that comes with warmer temperatures spins
clockwise, something Rogers said is called a “cross-Polar flow.”
Right now there’s
one above Alaska that’s dragging cold away from the Arctic and
aiming it at North America.
High pressure does
something else, Cohen said. It “perturbs the polar vortex.” The
pressure system and wind pattern tends to keep cold air up in the
Arctic unless it weakens, stretches or gets bent out of shape. When
that happens, frigid temperatures run south into North America, Asia
and Europe. And it may become increasingly common.
“The mechanics are
the same,” Cohen said. “What is changing is the loading of the
dice.”
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