Why Aren’t Forecasts Always Right?

Computer models make assumptions based on ideal atmospheric conditions. Most models are not global and only forecast for a set area, so errors exist along the boundaries because they are not accurately analyzed. Some regions, such as the ocean and at high latitudes, lack direct weather observations. The introduction of satellites have helped with indirect measurements. Larger weather features such as mid-latitude storms show up on a weather map, but smaller scale events such as thunderstorms may not. Models do not interpret factors that influence surface weather such as lakes and terrain.

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