One of the problems with spotting T-storms is the closer you get to the Sierra Crest the harder the are to see until look at Mt. Hitchcock from Trail Crest.
Here's another piece of advice. If Whitney covers up at Noon the day before your hike, make plans to be off the summit a couple hours prior to the time it was covered. This isn't a guarantee electricity will not be a problem but it minimizes it.
I've gotten T-stormed at early as 8 AM in the Sierra.
