How do you predict weather conditions based on an analysis of atmospheric data?

Answer 1

All of the weather data from all over the world collected by weather balloons that measure conditions throughout the troposphere is put into computer models. These computer models use millions of physics equations to interpretate the future movement of these conditions and how the conditions are likely to modify in time. It is a very complex thing and at the present time, it is impossible for enough data to be collected and processed to make weather forecasting exact at all times. This is why occasionally it rains when the weatherman says it's not supposed to. Weather forecasting has improved a great deal over the years, but it still is a bit experimental and no forecast can be guaranteed accurate at all times. The idea of weather forecasting is not to give the exact future weather conditions at all times (because that's impossible for any human to do at this stage of scientific advancement) but rather it's an opportunity to take advantage of what science has enabled us to do (which is a reasonable accurate forecast most of the time) to prepare people for upcoming weather to the best of current scientific ability.