So much for the ICON model and its forecast 2 metre air temperature for Altnaharra at o6 UTC this morning of 3°C. The Germans look like they have problems with that model because the temperature at 06 UTC was just a tad lower at -5.0°C at that time, so much for Vorsprung durch Technik ™. I find that the inability of models to forecast inland air temperatures a recurring theme each autumn. From what I can see the NWP models are unable to predict an accurate minimum air temperature, probably because the model resolution are still too coarse. Because of this weathercasters can’t be specific about it either in their graphics or what they say. And so it was in last night’s forecast, Chris Fawkes knew very well that they would be a frost, but couldn’t be specific about it’s extent or severity. I’m sure that if he had any idea that there was going to be a widespread moderate frost inland with minima of -5°C then I think he may have mentioned it.