Where people tend to get thrown is micro-storms during the summer months. They are basically impossible to predict accurately, at best it's just known that a random assortment of towns in a given area will received heavy rain for a short time. Being able to read radar is the best way to deal with this, but it's very short term only (15min to 1 hr).

Edit: I thought something was sketchy and rightly so, after searching for "Mid Atlantic Region" I learned that it's actually a region in the north-east US, not "the middle of the Atlantic". Well, learned something new today :)