I was at the last one, and two before it. They get scrubbed all the time; especially this time of year in Florida. Rainy season.
I went to Jetty Park, and wouldn't recommend it. There are better spots. The bridges are good, with an unobstructed view. Lots of viewing guides online. They're all a little lame with info, suggesting everyplace is good. Everyplace you'll see it, for sure...but not all are good.
It's amazing. Simply amazing. Indescribable. If you do make it, don't take pictures, don't video it...that all doesn't even come close. Just watch, as it's only a few seconds. A few seconds after takeoff, it's gone.
And make plans to surf cocoa, or WHATEVER as you wait for traffic afterwards.