I know that a majority of thunderstorms form in the daytime due to convection from sunlight heating in a moist, unstable airmass. Once the sun begins to set, these storms dissipate.
But on some mornings (in the summer, of course) I'll check my local NWS radar (in northern Ohio) before I set out for work and see that it's alive with storm cells that have popped up from seemingly out of nowhere. They are not existing storms that moved into the range of my local radar, but brand new cells that just appeared about an hour before. These storms usually contain a lot of lightning and bring sustained heavy rain, sometimes to the point of minor flooding.
What causes early morning storms to pop up like this when it's typically the coolest time of the day and convection is at a minimum? It's something I've been thinking about for quite a while now.