A critical element of the space weather research and forecasting is the development and use of models.
Models vary in form, content, context and sophistication.
On one extreme are the contemporary forecasting models, based on heuristic algorithms, statistical relationships, and human estimates currently in use in space weather forecasting and system engineering design. It is clear that physics based models, such as MHD, hybrid and particle codes, have played and will continue to play a critical role in answering researching questions. The important issue at hand is to what extent physics based models can, by themselves or in combination with statistical or non-linear dynamics models, become real time forecasting tools. In this seminar we will first review the types of models currently in use in space weather, with emphasis on their strengths and limitations. These examples will be used as aides in the assessment of the utility and limitations of physics based models in space weather and in addressing issues such as validation, testing and implementation of such models as research and forecasting tools.