Icing
Robert C: "Meteorology is such an exact science, that "severe" icing 50 miles southwest of Buffalo can be discounted since another flight made it on the same path only 27 minutes later."
I respectfully suggest you are wrong on two points there. First, there is no way that meterology -- of all the "sciences" -- can be described as exact, or anything close to it. The reasons for that, and the myriad examples, are for another thread, but to summarise: Accurately predicting the specifics of movement, dynamics, forces, and the resulting actual conditions in the atmosphere is not something we are (yet) good at. Those who know meterology -- along with chaos theory, and how it applies to met -- will tell you that accurate specific predictions of icing (ie: amounts, locations, altitudes) is just not on (if you're interested search: "the butterfly effect" ). General predictions are the best that can be done; the best predictors by far are recent pireps.
Which brings me to point 2: The conditions encountered by another aircraft (even same type) 27 minutes later may indeed be relevant. But they may also be completely irrelevant. In my (way too many) years I have seen aircraft 3 minutes, or 5 mins, or even 10 miles, apart on the same route encounter entirely different conditions. Weather (especially "heavy" weather) is extremely dynamic.