As for where rain comes from, why don't all you know-it-alls at least acknowledge the one basic fact of the creationist position which is that THINGS WERE DIFFERENT BACK THEN.
So things were different. They were so different that they were contrary to the laws of physics. But there wasn't any magicking.
Based on my understanding, the Flood had two sources from which the water appeared: the rain and the Fountains of the Deep.
1. Pertaining to the rain
Rain is the product of evaporation and condensation of existing water sources. i.e. while rain itself can cause localized flooding in one area, by the law of conservation of mass, another area would have had to give up 'X' amount of water to service that rain. Most of our rain has its origins in sea and ocean water evaporating and then condensing over land. Faith has indicated that the rain source in her scenario is the 'firmament'. However, there is an underlying problem here: a firmament of water encircling the Earth would have blocked out the vast majority of sunlight reaching the surface of the Earth, since photons can only penetrate so far into water. One only needs to go diving to moderate depths to realize this. Thus, the nature and function of the firmament and its permeability to photons is a violation of our known laws of physics.
2. Pertaining to the Fountains of the Deep
Since we don't actually know what these are, let me make some assumptions: they exist underground. There are several problems with this scenario, so let's go through them: Based on water levels needed, the volume of water required in addition to current ocean levels is massive. I have not done the math, but one can speculate that it was a lot. But to the main point, if the water was occupying 'X' space beneath the surface of the Earth, if that water then moved to the surface, the area that it was filling would then collapse. This is how sinkholes are formed. This would have far reaching ramifications on the topography of the Earth as its land mass would be devastated by this effect. Additionally, and more importantly, the water itself can only move based on pressure differences. For the scenario that Faith is describing to work, there had to have been some 'force' keeping that original water at bay prior to the Flood. This force (call it a plug if you will) was then released to allow the water to flow. If Faith can describe this force as some natural phenomenon, I would be interested in hearing about that. But there is one final point. The Earth is now flooded completely. Now, evaporation will cause some of the water to exist in a newly formed cloud barrier. However, the water which was sourced from the Fountains of the Deep has no way of returning to its origin since whatever 'force' was required to keep it at bay would now have to be invoked. And its not a simple plug anymore. It requires a pumping action of some kind. Once again, this is not a 'natural' occurrence.
And we don't even have to get into the whole argument about how the plants survived.