What are the factors that prevent long-range weather forecasting?
Knowing future weather depends upon knowing what the weather is doing now. Current weather readings are taken at surface stations around the USA and around the globe, as well as weather balloon observations that give a picture of what is happening in the atmosphere. This data is then used by computer models, systems of equations that forecast what the atmosphere will do given certain initial conditions. While computing power and additional observations have improved computer models, forecast accuracy still drops off after several days, with little reliability in forecasts that go out more than two weeks. The chaotic nature of the atmosphere reduces forecast validity with time. Rather than trying to predict day-to-day weather, long-range weather predictions do not attempt to forecast weather for a specific date or location months ahead of time. Rather, long-range forecasters predict regional temperature or precipitation compared to past climatological averages, using current atmospheric
