I checked your airport link and the weather was quite similar to the main Orlando site I used, 80's from about noon to 3 pm.
One difference in our perspectives, I think, was the timeline on 6/16/08. I was specifically looking at 1-3:30 pm time, just before the "flurry" of phone calls from Casey to Mom/Dad, etc. Could a small child have gotten overheated in a closed car at that time?
As you can probably guess from my boat in the pic (Southern Star), I sail a lot and tend to be constantly checking radar, tides, etc. It's a lot a more accurate when you're checking past dates!
Thanks and take care, melly53.