Aside from a light rain on a hot day, riding in the rain sucks in general. Dangerous enough in a hard rain due to lose of visibility of you by other drivers. You don't want to add a t storm on top of that danger.
It really depends on how scattered the storms are. I have ridden on days of scattered t-storms. When he downpours start or t-storms start I sought shelter to wait it out.
If it is really that bad that it is all day then I would just pay for a motel room. It would really suck to be stuck in a tent for 2 or 3 days.