(Image source: DMI)
Today the Persistent Arctic Cyclone of 2013 (PAC), re-centered over the North Pole even as it wrapped itself in above-freezing temperatures.
The above image shows a double barrel low roughly centered over the North Pole with a second low adjacent to the Canadian Arctic Archipelago. Lowest pressures remain around 980 mb — a rather potent storm for early June. Though not likely to grow as strong as the Great Arctic Cyclone of 2012 (GAC), this particular storm has now lasted for nearly two weeks and is projected to remain in the Arctic at least until June 15. Such persistence is likely to make this storm a substantial factor in the ongoing melt season.
Yesterday, the storm drew warm air in from the south behind it. This influx of warmer air ran into the Central Arctic beneath a train of cloud over a region near Svalbard and was visible in this Lance-Modis satellite shot. Temperatures in the region of Svalbard rapidly warmed with some regions there reporting 50 degree temperatures today — a virtual heat-wave for Svalbard this time of year. An area of dispersed ice near Svalbard also suffered very rapid melt yesterday, likely a result of this flood of warm, moist air.
Regions near the North Pole now show near freezing and above freezing temperatures. The storm backed into this warmer air, becoming wrapped in it as it returned to the Central Arctic. You can see this plume of warm air on the storm’s right flank in the DMI image below:
(Image source: DMI)
This above-freezing air now resides over a region where sea ice remains broken and churned by previous passages of this storm. This region is heavily obscured by dense cloud cover. However, we can get a few peeks down through the clouds in the latest Lance-Modis shot of the region. What detailed inspection reveals is the ghostly image of shattered ice with large, dark gaps of ocean water between. These gaps have likely emerged through the physical process of storm winds diverging the ice as cyclonic forces churn the protective, cold top layer of water with warmer layers underneath.
This assault from below is now enhanced by the fact that near freezing and above freezing air has moved in overhead (seawater melts at around 29 degrees Fahrenheit).
A close look at the image below reveals these gaps:
(Image source: Lance-Modis)
The clouds in this image are quite thick. However, if you took slightly to the left of direct center, you’ll be able to see ghosts of the fragmented ice and large gaps beneath.
The US Navy’s most recent CICE model run shows the PAC delivering a sustained blow to the thick ice just north of the Canadian Arctic Archipelago (CAA) before impacts are again projected to increase over coming days in the Central Arctic. Note the shifting of yellows and reds to greens and blues near the CAA. This is indicative of a loss of about a meter or more of sea ice thickness in this region. Also note the more wide-spread thinning that is expected to re-emerge near the North Pole as light blues in the model run fade more toward darker blues, showing about an additional half meter loss there.
(Image source: US Navy CICE)
Confirmation will be necessary both visually and in other measures in order to verify the losses shown in CICE. Early losses were confirmed in Uni-Bremen, Lance-Modis visuals, and JAXA. However, dense cloud cover is currently making confirmation difficult even though some hints of this ongoing damage are visible through the clouds.
As mentioned yesterday, the primary processes for melt occur through divergence of the sea ice as well as via churning, upwelling, and Ekman transport of warmer water up from the depths. Today, melt potential is added via near and above freezing air temperatures over large regions of the Central Arctic. And as we’ve been warning since last Friday, the sustained nature of this storm has the potential to severely weaken the Central Arctic ice just prior to the warmest days of summer.
Since yesterday’s May PIOMAS update we’ve had more news to consider. However, apparent central ice impacts from this storm didn’t begin to seriously ramp up until the start of June. So we may need to wait to end of June for more clarity on total impacts. Nonetheless, all indications are this storm continues to fling the sea ice about quite a bit, with CICE continuing to show significant impacts to central ice thickness.
So, for now, the big thin continues.
Warm, moist air influx from the south appears to have provided this storm with some added intensity. What, earlier, was a double barrel low pressure system has now combined, drawing warmer air toward its center as its intensity increased to around 975 mb. Now this storm is just about 9 mb shy of the Great Arctic Cyclone of 2012’s maximum intensity. In any case, 975 mb is a very respectable storm.
You can take a look a the latest storm intensity map here:
(Image source: DMI)
ECMWF weather forecast model runs for June 14 show PAC 2012 deepening to a 965 mb low pressure system. Should this strengthening occur, the system will have become stronger than the Great Arctic Cyclone of 2012. With the storm lasting so long, if it reaches such a strength, we may be dubbing it the Persistent Arctic Megastorm 2013 (PAM). Definitely something to keep an eye on.