Looking at the parameters relevant for cyclogenesis on isobaric as well as on isentropic surfaces (Vertical Cross Sections) there are many indications for a rapid cyclogenesis going on. But from the optical impression this case starting in polar latitudes develops differently compared to the well-known rapid cyclogenesis developments starting in the mid-latitudes over the Atlantic.
From the optical impression one would say that a Cold Air Development takes place. And some of the parameters do indeed support this, but the comma spiral from which the synoptic-scale spiral develops is not in the cold air but (probably) at a baroclinic boundary in the cold air.
Another very interesting feature of this case is the period of several hours during which very small scale curls develop at this boundary under the influence of dry air in upper levels which represents a PV anomaly.