Monday, 9 May 2016

Arctic heatwave this week

As I mentioned yesterday... the latest from Robertscribbler.

Warm North Pacific Winds Predicted to Usher in Brutal Arctic Heatwave this Week

8 May, 2016

Sprawling over the Northeastern Pacific, there’s a big, doggedly-determined high pressure system. One grown to enormous size and influence in a global atmosphere boiling with the heat of fossil-fuel laden airs. A weather system that’s now able to stretch out a long arm of influence into the High Arctic due to an unrelenting northward shove of oppressive record global heat.

Beaufort Sea Ice Shattered
(The Beaufort Sea Ice has been shattered under the weight of a relentless a high pressure system that has dominated this region of the Arctic for about a month. Now, a freak early-season invasion of above-freezing temperatures is set to level another melt-forcing blow at a region that is very sensitive to the worsening impacts of human-caused climate change. Image source: LANCE-MODIS.)

Extreme Fires, Sea Ice Loss in a Context of Ever-Worsening Climate Change

Beneath the high, much warmer than normal airs have settled in over the Northeast Pacific, over Western Canada, and over Alaska. These much hotter than typical temperatures have provided fuel for a raging start to fire season in such far northern regions. In Canada, nearly a hundred and fifty fires now burn

Sparked by never-before-seen heat and dryness, the worst of these blazes has now consumed 620 square miles of land and more than 1,600 structures around the city of Fort McMurray — forcing about 90,000 people to evacuate and threatening Canada’s hothouse gas emitting tar sands production facilities. Meanwhile, in Alaska, the heat has been lighting off forest fires since as early as February. A month that once only featured a climate of deep chill and heavy snow — but one that in the new, greenhouse gas warmed, world features an ominous winter burning.

The high has also extended it atmospheric influence up into the Polar zone — joining a powerful ridge that has torn away and shattered sea ice across the Central Arctic since at least mid-April. Opening wide areas of dark, heat absorbing water and contributing to never-before-seen low levels of sea ice extent and volume for May.
May Arctic Heatwave Builds

As of Sunday, this lumbering high began a big shift to the west — expanding its influence on into the North-Central Pacific and the Bering Sea. There, it rallied a warm flood of airs in the form of northbound winds. Warm winds now readying to make a big push into the Arctic Ocean later this week.
(Huge northward thrust of warm air seen in this Earth Nullschool capture for predicted May 12 conditions. Note the large swath of above-freezing temperatures invading the Arctic Ocean as readings in Northern Alaska and the Northwest Territory of Canada hit the upper 60s and lower 70s. Regions that are typically still covered in snow experiencing conditions that would be somewhat warmer than normal May weather for the US West Coast city of San Fransisco more than 2,000 miles to the south. Image source: Earth Nullschool.)

These winds are expected to build northward along a warm frontal zone over Northern Alaska and the southern reaches of the Beaufort and Chukchi Seas on Monday. Linking up with two low pressure systems forming over the East Siberian Sea by Wednesday morning, this wave of heat rising out of the Pacific is expected to have expanded into that sea and taken in all of the Chukchi and half of the Beaufort. By Friday, this northward drive of above freezing airs is expected to have taken in about a third of the Arctic Ocean region in total.
Over Alaska and the Northwest Territory near the Mackenzie Delta, temperatures are expected to rise into the upper 60s to upper 70s Fahrenheit (20-25 C). These are temperatures 20-28 degrees F (9-16 C) above average for early-to-mid May and readings seldom seen for this region even during June. Such high temperatures will hasten melt of any remaining snow or ice and spike fire hazards over this Arctic zone.
Extreme warm temperature anomalies over Arctic zones predicted for May 13
(Two lows on the Siberian side of the Arctic and a high over southern Alaska and the Northeast Pacific are predicted to drive an extreme level of heat into the Arctic starting Monday and continuing on through the end of this week. This extraordinary northward thrust of warmth appears set to tip the scales swiftly toward high Arctic thaw conditions that are typically experienced during June. Such a high degree of added heat will have a profound effect on both sea ice and remaining snow cover. Image source: Global and Regional Climate Anomalies.)

Savaging of the Sea Ice to Continue

Over the Arctic Ocean, conditions will arguably be worse. Temperatures in the near coastal waters of the Beaufort Sea could rise to as high as 41 degrees F (5 C) while temperatures in the range of 32-38 F (0 to 3 C) are expected to cover a very wide zone of Arctic waters invading about 600 miles of the thinning sea ice area between the Mackenzie Delta and the North Pole and covering a breadth of around 800 miles from the Canadian Archipelago to the shores of the East Siberian Sea. These temperatures are also 20-28 F (9-16 C) above average and are more like the atmospheric readings one would expect during July over these typically frozen Arctic waters.
It’s not just the high temperatures that are a concern with this invasion of extreme heat running into the Arctic. It’s also its sheer scale — taking in about 30 percent of the Arctic Ocean zone, most of Alaska, a large region of Northeast Siberia, and a big chunk of Northwest Canada. Such a huge warm air injection will be taken in by the larger circulation over the Arctic Ocean and greatly shrink the remaining pool of cooler airs — driving temperatures to push more rapidly above freezing.
Freezing Degree Day Anomaly
(Off-the charts record Arctic heat shows up in a -1012 freezing degree day anomaly during 2016. In an average year, the Arctic experiences about 6,000 freezing degree days. We’ve lost more than 1/6th of that during 2016, which is basically like knocking one month out of the Polar Winter. Image source: CIRES.)

To this point, temperature anomalies above the 66 North Latitude Line are predicted to continue in the range of 2.5 to 3.5 C above average for the entire Arctic region into mid-May during a time of year when readings tend to moderate. In other words, this range is well above average for this time of year and continues a trend of record Arctic heat for 2016 that began during January. One that has now pushed freezing degree days (FDD) to a never-before-seen -1012 anomaly — which is like losing one entire month out of the coldest time of year in the Arctic.
The severe Arctic warmth continues to have a profound impact on Arctic sea ice — pushing measures inexorably into new record low levels. As of today, pretty much all the major extent and volume measures showed sea ice at new record daily lows and indicated a pace of melt at start of season that is absolutely unprecedented. Of particular concern are volume measures which have rapidly closed and overcome the gap between previous record low years.

DMI sea ice
(DMI’s sea ice volume measure enters a new record low range during early May. Note how swiftly comparative sea ice levels have fallen since February and March of this year. In essence, we are currently just below the record low 2012 launching pad all while facing an unprecedented level of heat building up in the Arctic. Image source: DMI.)

In this context of extreme Arctic heat and already record low Arctic sea ice levels, we continue to expect new record lows to be reached by the end of the melt season — pushing past one or more of the low marks set during 2012 and possibly testing near zero sea ice ranges (blue ocean event) of 80 percent volume loss since 1979 and below 750,000 square kilometers of sea ice area and 1.5 million square kilometers of sea ice extent by September of this year.

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