Im guessing you are reading from an undergraduate thermodynamics textbook and pretending to be an expert.
This guess, I can tell you, is wrong. The rest is your opinion.
There are many, many things we don't know about the arctic. If you have a theory great! But don't call it "established scientific fact" unless you can point to undisputed peer reviewed journal articles that have established those facts through observational data.
Ok, perhaps it is the way Wayne asserted that "surface temperature". Does he mean water surface? In which case I don't have to go to any peer-reviewed paper: the continuity of temperature across the interface of bodies on different states (solid-liquid-gas) is something I have measured in the lab, imposed as boundary conditions in the computational lab, and frankly I hope it is "common understanding" in this high-level educated forum.
If he means 2m temperature, or temperature measured at land nearby the coast where he is or was doing his ice measurements, then that is a different story. I suscribe to what Binntho and Tor say above. A temperature well under freezing (as measured in land, near the freezing ocean) is required for a period of time because water is releasing its latent heat, and if you go down near the water and place a thermometer near the surface, it will be nonetheless -2C. That the (land) temperature has to be under -11C, for some uncertain period of time, well I doubt it. Everything will depend on which sea is this being measured and what type of sea (shallow or deep, salty or less salty) it is, if ocean currents reach the place, what was the ocean temperature at the surface and in depth to start with, if the location is open coast or some narrow inlet, etc etc.
Then we have temperatures well into the ocean. As people are observing these days, freezing is happening with now-casts showing 2M air temperatures of around -5C. Not so far from -1.8C. This year, for instance, the Beaufort sea has not warmed as much as other years during summer, so we are observing this flash refreeze around the ice remains that almost disappeared. The reason is simple, temperatures did not build up much above freezing, and not much time and not much low temperatures are required to get the water surface at freezing temperature and the overall heat balance negative. Ocean in relative calm, absent of heat transport from beneath, and of mechanical effects that would delay the formation of sizeable ice structures (not the delay of freezing certainly), well there you go.
It is nothing against the person of Wayne, but he has a PUBLIC blog where he does PUBLIC claims, and as such one can criticize his public persona for doing such bold claims that, honestly, do not make much sense to me, and open up the door to pseudo-science. Like Goddard, Watts, Trump and the likes are routinely (and correctly IMO) criticized here.