In general, models are good for determining the probability of mid to large scale weather events.
Models are very CPU intensive and therefore, costly to run.
Standard mathematical atmospheric models used to project what the weather will be for a specific geographic location for some period of time in the future. Typically each model forecasts pressure, temperature, wind speed and heading at various heights in the atmosphere, and relative humidity and precipitation amounts. For practical purposes, models that forecast in excess of 4-5 days are only good for indicating tendencies in the weather pattern, and cannot be used to identify specific local weather occurrences. Each model is fine-tuned to support particular needs. El Nino Southern Oscillation.