Prerequisites:

Description:

    This is the technology of changing the weather predictably.  Changing the weather simply is easy, just explode a large nuclear weapon and the weather will be different than it otherwise would.  Changing it in such a way as to get what you want is another matter.  First you have to know what the weather will be in a given time period if you do nothing, and then you have to figure out what you want the weather to be, and then you have to figure out how to make that happen.  To do the first and last part above, you need very accurate simulations of weather phenomena.  Better simulations, and the ability to do them more quickly (ie test out many different possible weather modifications before doing them) will allow weather to be modified with less power input. 
    The best way of modifying the weather, once you know how, is to beam power down on the appropriate spot at the correct frequency.  For example, a beam of infrared energy in the middle of this thunder storm might reduce it (or make it stronger, depending on your goal), giving the correctly altered weather.
    Idealized weather allows for planning of a type the real world has never seen.  If a farmer knows exactly what weather has been planned for the next 200 days, it is easy to figure out what day to plant, when to fertilize, when to water, etc.  Farming becomes nearly algorithmic (and it makes robitic farming more of a possibility).  Transportation is similarly improved; if there is a severe rainstorm scheduled for 3pm on Friday, then no airplane flights are scheduled in the area at that time.