Water in thunderstorms?

Question

OK, I understand how water heats up into "steam" and goes up into the clouds. After a while the clouds get so full of water "mist" they cannot hold the water any longer, the water falls to the ground, in the form of rain. When the cloud has no more water in it, the rain stops...

So what happens when a rainstorm rains, and rains, and rains?. We had it rain 24 hours-a-day for an entire week. Where did all the water come from?

Answer 1

When you seem to have day after day of rain and their is not hurricane in sight you are likely under a stalled occluded front.

In this situation cool high pressure air (cold front) is coming at you from on direction while warm low pressure air(warm front) is coming at you from the other direction.  The warm low pressure air rises over the cool high pressure air causing it to cool down.  Because cool air can not hold as much moisture it begins to rain.  

If the boundary between fronts is above you for several days then air can gather moister over water and be pulled hundreds of miles inland to be dumped over you.  The key to remember is the clouds are moving so while one cloud might be "empty" and new "full" one takes its place.

Answer 2

could be tropical depression which is just a gathering of clouds. or a tropical storm which is basically the same thing except the water is from the ocean therefore it will have much more rain than a usual rain cloud