The NAM, or North American Model, is a weather forecasting model produced by the National Center for Environmental Prediction. The NAM is the common name for the WRF, and is nested within the broader framework of the GFS. That is to say, while the NAM operates only over the continent of North America, it gets its forecast information at the edges of its forecast region from the GFS.
Because of the smaller spatial area that the NAM covers, it has unique advantages and disadvantages. The primary advantage is greater resolution, which is advantageous when looking to forecast convection in the short range, rather than necessarily looking to prognosticate long range, synoptic scale features. The NAM is unreliable when foecasting further out than a couple of days because of it’s narrow scope, and disconnect with the outside world when the forecast valid time gets further into the future.