To Mule...yes you are correct, a rising barometer tends to indicate fair skies, 'improving weather,' as with a high pressure cell. And, in this case, we did have clear skies, at least from this report the previous night. But, that's just a guide and doesn't necessarily mean that's what you'll get. Fact is, high pressure cells can allow mid to upper level clouds (overcast to an observer, and somewhat appears to have happened on this afternoon), and you can have thunderstorms develop near high pressure. Falling air (rising barometer) tends to fight against that, but not always. In this case, it may have HELPED surface fog develop, which is where the problem started and very well may have stayed.
Getting to another point raised here about fog aloft, that's not where the problem was created and remained. The surface was the problem. I haven't seen a vertical profiles of the atmosphere on this day (which measures temperature and dew point from the surface up), but, based on the surface observation where people lived, the air was clearly saturated. Further, with falling air, (rising barometer), the surface moisture would have been trapped and I suspect an 'inversion' developed, which is a cap to repel further mixing with air aloft. In other words, it made matters worse.
So, briefly, we have some scattered showers/drizzle, moisture deposited at the surface on Saturday. Skies open up overnight, based on the hourly comments. Perfect, that allowed the surface to cool, and NOT mix with, what I suspect drier air aloft, surface fog develops. Sun comes in to clear skies, but the surface is muddied in fog. As the sun heats the earth, that starts surface winds and into mixing with drier air, fog 'mixes out.' I have no troubling believing by 8 AM, 'sunny skies.'
The hourlies, by the way, are averages from the previous hour's activity and it is clear that during the 7 o'clock hour conditions markedly improved.
But, 6 AM, the details of a 'woman who looks like Suzie' in 1970's model van, too much for me to accept.
These observational reports tell me a couple things. For one, the perp(s) probably had good cover at the house, although that doesn't mask sounds, it would have helped keep things more mysterious from any curious eyes watching, any cars that passed by and so on. Two, if 'porch lady's account was in fact at 6 AM, I don't accept any of her details beyond; a motor vehicle, an apparent male's voice, and this vehicle pulling in a driveway and pulling back out with some human presumably driving it. Buuuut, if it occurred later, these details become that much more credible. Fog can give the impression it is earlier in the morning, than it is. And, after forecasting weather in the Ozarks for a few years, with volatile thunderstorms and tornadoes, fog was never much of a talking point.
Lastly, to the point about AC, absolutely, only a fool would be running their AC overnight in this case. Not only that, true to form of a late Spring/early Summer in the Ozarks with all this moisture; It's 'stuffy' in the late afternoon/early evening, yet bone chilling, damp cold in the morning.