Usually there are a bunch of towering cumulus that look like they might become storms at 1 PM, only for the entire cumulus field to slowly fall apart by 5 PM. The sun gets progressively more clouded as the anvils from thunderstorms out west inch their way over and the final outcome is a couple lightning bolts, moderate rain and cool clouds to boot.
That's at least how it was half the time back on the Delmarva