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Numerical Models
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Numerical forecast models are produced by a variety of agencies on
both a regional and global basis. Numerical models start with an
initial set of conditions and use equations to predict conditions at
various time intervals into the future. For this reason, model 
intiialization is of critical importance to the accuracy of the
prediction.

Models have a horizontal, vertical and temporal dimension. They
can consider data on a global scale, a continental scale or a regional 
scale. The global scale models can be used to predict synoptic or
long-range weather conditions. The continental models are meso-
scale and can be used for medium-range predictions.