After scattered thunderstorms Thursday afternoon and evening, the pattern dries out a bit Friday and Saturday, resulting in mostly sunny skies (although a few afternoon clouds are possible, especially in the mountains.) Temperatures will remain quite warm…in the mid-90s through the weekend. By Sunday we will begin to see a little more cloudiness in the afternoons, with a slight chance that a few of those clouds could produce an isolated thunderstorm or two.
Yesterday, I mentioned that there is a separation of charges in a thunderstorm. Sam Asked: “OK fine, but how does the upward movement of air create a separation of charges? I suppose it’s the same as shuffling across the floor and getting a shock, but the question remains: Why?” Actually, it’s different than shuffling. The collision of hail going down and the rain going up is the crux of the cause. Electrons are ripped off the rising particles, which causes a net positive charge on the tops of the clouds, and a net negative on the bottoms. We are still learning about the exact processes involved, but it is much more involved than just a straight static electricity buildup.
A Word of Weather 
I have a weather question that I have always been curious about. My understanding is that though flash floods bring a lot of water in, really fast, it really does not help the drought much, long term. So my question is, if there was a flash flood above lake Tahoe with a substantial amount of rain (and the lake gets most of the rain in it), would that be more beneficial to our area’s drought situation, or would it not make enough impact on the lake level?
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The problem with flash flooding with respect to helping with any drought is that although they can put a lot of rain down in certain areas, the areal extent of the individual storms is very small. A flash flood-producing thunderstorm over Lake Tahoe may put an inch of rain down in some areas, but you are probably only talking about 5-10% of the lake’s surface, so an inch of rain out of that type of storm would probably only raise Tahoe by a tenth of an inch or less. While every little bit helps, it’s probably not going to make a noticeable difference.
The real important time of year is the winter months when it comes to our water supply.
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