Originally Posted by songsc

Unless the delayed is posted well in advance, you may still need to be sitting on the aircraft or waiting near the gate around the scheduled departure time.

I know this isn't what you are originally asking for, but other than YFC, there are quite a few places along the eclipse belt with favourable weather forecast, and are just a short drive from GTA, such as the south shore of Lake Erie, and Brockville/Cornwall area. Montreal and Eastern Townships in Quebec are also forecasted to have sunny weather.