Today, clouds parted enough over the Central Arctic to give us a visual of the ongoing damage inflicted by 2013’s Persistent Arctic Cyclone (PAC). And the damage, as we can see in the images below is extensive.
For comparison, I have provided this shot, taken on May 26th, just as the PAC was beginning to ramp up. Note how pristine and mostly crack-free the ice looks in this satellite shot. Though areas of leads and cracks exist, they are comparatively minor, small, and diffuse.
(Image source: Lance-Modis)
Today’s most recent Lance-Modis shot shows conditions that are radically different. Note the broad, black spider-web of cracks that has come to dominate this large region of the Central Arctic Ocean. The only places where these large, angry cracks aren’t visible is in areas still covered by dense cloud:
(Image source: Lance-Modis)
Uni-Bremen sea ice concentration assessments have now been showing confirmation of the storm’s thinning action for more than a week. Today’s concentration graphic provides yet one more validation of central area sea ice losses.
(Image source: Uni-Bremen)
This is the wreckage 18 days of constant pounding has inflicted upon some of the Arctic’s most resilient sea ice. One doesn’t have to think too hard to imagine what another 18 days of such pounding may look like. The Navy CICE/HYCOM model run further on in the post gets us less than half-way there. And weather forecast models show PAC 2013 remaining in the Central Arctic at least until Wednesday of next week.
PAC Positioned Near Warm Air Influx
(Image source: DMI)
The current pressure map shows the cyclone centered near the North Pole. Incorporated in its circulation are two weaker storms — one near the Kara Sea, the other over the East Siberian Sea. Lowest pressures are in the range of 990 mb.
Over the past few days, warmer air has been flowing into the Arctic from the region of Alaska and Kamchatka. This warmer air is embedded throughout the Arctic and is, largely incorporated into the circulation of our cyclone. So a substantial portion of the Central Arctic shows above freezing temperatures at this time:
(Image source: DMI)
Model forecasts show this warm air influx continuing to grow over the next week with above freezing temperatures covering larger portions of the Central Arctic as time moves forward. Above freezing temperatures are rather common this time of year. What is less common is for cold-core Arctic storms to host such temperatures, even during summer time.
A Constant Influx of Storms
One of PAC 2013’s unique features is its ability to consistently gobble up smaller storms. Storm after storm has arisen from the south, only to be subsumed by the Persistent Arctic Cyclone. This constant infusion of energy from the south is, likely, one of the features that has allowed PAC 2013 to last as long as it has.
Model forecasts show this trend continuing until at least June 19th. At that time, the cyclone is shown to transition to the Canadian Archipelago, as weaker storms trail along through the Central Arctic behind it. This projected storm track brings PAC 2013 on a path directly through a region of the Arctic’s thickest ice just north of the Canadian Arctic Archipelago.
Throughout this period, PAC 2013 is expected to maintain a strength between 990 and 1000 mb — about the intensity of a moderately strong tropical cyclone, but diffused over a much larger area. Current projected storm track and strength show that it may pose a risk to fracture, disperse, and thin a section of ice that has been, thus far, left relatively unscathed.
Here is the ECMWF model forecast showing the storm’s predicted position on June 18th:
(Image source: ECMWF)
That puts a moderately strong 995 mb storm directly over the thickest part of the ice pack sometime next Tuesday.
Fram Strait Export
The constant counter-clockwise motion of PAC 2013 has also begun to have a substantial impact on the remaining thick ice near Greenland and the Canadian Archipelago. Since late May, this region has shown a thinning at the edges and a consistent motion toward the Fram Strait.
This motion is plainly visible in the US Navy CICE model history and forecast from May 23 to June 20 (posted below). Note the large front of greens and yellows (denoting thicker ice) pushing steadily toward the Fram Strait between Greenland and Svalbard.
It is also worth mentioning that the amount of thinning forecast for a region from the North Pole to the Laptev Sea is astounding. Later days in the model forecast show this large region of thinning starting to wrap around the North Pole in the direction of Svalbard. The US Navy projects this region to include large areas of 0.75 meter thickness or less opening up in this region by June 20th. Bands of thin ice seem to be forming a ring pattern emitting out from the North Pole. A stunning effect more reminiscent of disaster movie graphics than actual weather forecast models. Should this forecast thinning emerge, it will be nothing short of remarkable.
(Image source: US Navy)
In conclusion, PAC 2013 continues. Though some models show the storm transitioning to the Canadian Archipelago by after June 20th, the storm appears likely to continue to impact one region of the Arctic or another for the time being. At 18 days, this is a very long-lasting storm, especially for early summer. Yet models show the potential for the storm to persist and continue to have impacts, having lasted at least 25 days by the end of some model runs.