How accurate would it be? Even if you can predict with, say, 95% accuracy that a thunderstorm will cause a launch scrub, SpaceX might want to give it a try anyway in case that 5% comes true. They want to launch ASAP, and they'd look dumb if they called it off only to find that the weather was fine.

Accurate forecasts are no doubt extremely valuable in many cases, but for this specific case I don't see it changing much.