Does a red sky at night really mean nice weather ahead?

Chris Smith put this question to Jim Bacon from Weather Quest...

Jim - I kind of have a soft spot for weather sayings, because when I was younger I used to work on a farm, and the guys there would have a great innate knowledge of what the weather did, and they would use these weather sayings as if they were kind of gospel, and most of the time they are, and what I like to do as a meteorologist is to look at some of them and think what would be the physics behind it. So the ‘red sky in the morning shepherd's warning’ and so on, is to do with the fact that in general, these were developed developed at times before we understood meteorology. So it's going back to the Middle Ages and before, when people had to try and remember what a certain sky meant, and red sky in the morning means the sun rising in the east is shining on clouds coming from the west, and most of our weather comes from the west. So it was a sign of bad weather. And red sky in the evening, you know, was the reverse, and it meant that the sun setting in the west was shining on the clouds going away to the east, and therefore the bad weather was going away. So weather proverbs are not without value. They've been honed over the years. The trick is really to know when to get them out the tool box and when to leave them in there, because they don’t always work.