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Arctic Air Temperatures are Set to Hit 35 to 55 F Above Average by Thursday — Out of Season Sea Ice Melt Possible, Again
“It
looks like a triple whammy – a warm ocean, a warm atmosphere, and a
wind pattern all working against the ice in the Arctic.”
“Unfortunately,
Arctic sea ice extent growth has once again slowed this week…”
“Huge
surface air temperature anomalies over the Arctic this working week…
over 25C warmer than average in parts.”
****
6
December, 2016
This
year, it’s a challenge to find a time when the Arctic Ocean has
ever represented anything resembling normalcy. Record
low sea ice extent values have occurred for more than 50 percent of
days measured.
And well above average temperatures have invaded the Arctic during
winter, spring, and fall. With another huge wave of ridiculous warmth
building up over eastern Siberia this week, the hits just keep on
coming.
Major
Warming Over Siberia, Chukchi and East Siberian Seas
The
present big warm air invasion has its origins in the Pacific Ocean.
There, a large high pressure system over the Bering Sea is facing off
with a strong low moving up across Kamchatka. Running between the two
is a powerful south-to-north wind pattern.
(A
major warm wind invasion of the Arctic on Thursday is originating in
the subtropical Pacific. A ridge in the Jet Stream extending all the
way to the North Pole is pulling this big bulge of warm air north. As
a result, extreme temperature departures and out of season sea ice
melt for the impacted zones are likely. Image source: Earth
Nullschool.)
As
we can see in the image above, the flood of warm air has its origin
around the 30 north latitude line. It flows directly over hundreds of
miles of ocean, at times reaching a storm-force intensity near 70
mph. As it crosses into Siberia, the wind slows down. But it
inexorably continues north, ever north — driven on by a serious
pulse of atmospheric steam. By early Thursday, the leading edge of
this warm air outburst from the Pacific side will have crossed the
Pole and led to a flushing of Central Arctic air out into the Barents
Sea and North Atlantic (you
can view an animation of the predicted warm air pulse here).
This
strong northward flood of warmth from the Pacific is running up under
an extreme high amplitude wave in the Jet Stream that is bellowing
out into the Arctic Ocean through the Bering and Chukchi seas. At its
peak northward extent, the big Jet Stream wave is
predicted to look something like this.
And it is this severe contortion in the upper level wind pattern that
has enabled this most recent extreme warm wind event to occur.
This
pattern is now in the process of injecting above-freezing air
temperatures into Eastern Siberia. By tomorrow, the warm air mass
will encounter the coastal regions of the Chukchi and East Siberian
seas. There, it will push temperatures as high as 2.5 C (37 F)
over zones that typically see readings in the -20s to -30s (Celsius).
As a result, temperatures will range between 20 and 30 C (35 to 55 F)
or more above average for many locations.
(Climate
Reanalyzer has
added a new color — white — for tracking extreme departures in
temperature. In the positive anomaly column, we find departures
hitting 30 C, or 54 F, above average for regions of East Siberia and
the local Arctic Ocean.)
To
be clear, these temperatures are highly abnormal. If a similar
temperature departure happened in Gaithersburg, Maryland on December
8, it would produce 80 to 100 degree (F) readings. Of course, this
anomaly is not happening in Gaithersburg. Due to a global warming
related process called polar amplification in which the poles are
more sensitive to alterations in rising greenhouse gas levels (due to
fossil fuel and related emissions), extreme temperature anomalies
tend to occur at the poles as rates of relative warming are 2-3 times
faster in those regions. And the factors that we observe associated
with this new Arctic warm wind event — powerful south-to-north
meridional air flows coupled with extreme high amplitude waves in the
Jet Stream — are also evidence of a number of weird new atmospheric
circulation patterns that can tend to pop up as polar amplification
intensifies.
Warm
Winds May Cause Unprecedented Back-to-Back Fall Sea Ice Melt
The
Pacific side of the Arctic has already been gaining heat ahead of the
oncoming warm wind event over the past few days. And what we have
seen, as a result, is a pretty severe loss of ice in the Chukchi Sea
during early December. To be very clear, Arctic sea ice should be
advancing at this time of year. But what we see in the image below
(provided by A-Team
over at the Arctic Sea Ice Forum)
is advance followed by retreat as the warm wind event starts to ramp
up.
(Ice
refreeze in the Chukchi advances until it is rolled back by the most
recent onrush of warm air flowing in from the Pacific. Image provided
by A-Team at Neven’s Arctic
Sea Ice Forum.)
Of
course, the retreat seen above has occurred before the main force of
warm southerly winds — due to hit the Arctic Ocean region by
tomorrow. So the risks for continued losses in the Chukchi extend for
at least the next few days. Losses there could be offset by
large enough gains elsewhere to continue an overall seasonal freeze
trend. But so far, with
abnormal warmth also periodically building in over the near-Svalbard
region and
with Hudson Bay refreeze continuing to lag, that does not appear to
be happening.
Looking
at the larger monitors, we also find that, as happened during October
and November, the pace of overall sea ice growth has stalled.
According to JAXA, over the past 4 days, sea ice extent has only
grown by 50,000 square kilometers. During a typical similar four day
period for this time of year, growth would tend to average around
400,000 to 500,000 square kilometers. And with values at current
record low levels, the inertial impetus for ice growth would be
higher. That is, unless the climate state of the Arctic has radically
changed — which appears to be the case.
(According
to JAXA, Arctic sea ice extent has again hit a plateau when it should
be freezing — this time at around 10 million square kilometers. As
sea ice follows that line, record lows are again deepening —
hitting near 800,000 square kilometers below previous lows for the
day in 2015. Considering the fact that another major warming event is
building into the Arctic Ocean, this plateau could again tip into
melt as happened during the middle of November. Image source: JAXA.)
During
mid November, a period of unprecedented warming produced an
almost unprecedented period of fall melt.
A similar November melt occurred during 2013. But
the amount of melt then was smaller.
And that melt did not occur at a time when Arctic sea ice values were
at new record lows — as they were throughout the entire month
during 2016. Similarly, during October, abnormally warm conditions
produced an odd re-freeze plateau similar to the one we are now
experiencing.
Given
current conditions, there’s a risk that we could see a December
melt event following the
November melt event.
For the amount of heat hitting the Pacific side of the Arctic is
predicted to fall far outside of normal temperature ranges. And,
barring major refreeze on the Atlantic side, we are at a rather
higher risk of seeing the present plateau in sea ice values carry on
for a number of days.
Links:
Hat
tip to John Allen
Hat
tip to A-Team
Hat
tip to Ryan in New England
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