Minimum Temperature Goes Nowhere

Despite my best wishcast, the temperature went absolutely nowhere last night at KSLC, remaining at about 8-10F for the entire night.  This occurred despite light winds (calm at times), clear skies, and low dewpoints, especially toward morning.

The minimum thusfar is 8F, and there's no way it will drop into the negative numbers.  What a waste of a perfectly good arctic airmass!

It is really quite remarkable that the temperature at KSLC did not drop at all.  Data collected for the PCAPS field program may shed some light on this, but I can't help but hypothesize that radiational cooling of the Earth's surface was countered overnight by the ground heat flux (i.e., heat flux from depth toward the surface).  If we had snow on the ground, the result would have been much different (and colder).  The magnitude of the ground heat flux is somewhat large at present because this event is so anomalously cold.  Thus, it may have put the breaks on the nocturnal cooling.

Other ideas?