I am producing a Space Weather forecast system with my sponsor, the UK Met Office. My work will produce forecasts and nowcasts to mitigate harmful space weather effects, such as GPS positioning errors, power system failures and the re-routing of transpolar flights. The system is the first to use a coupled model of the upper atmosphere in a data assimilation scheme, and will provide a capability that does not currently exist in the UK. I am collaborating with the US National Center for Atmospheric Research (NCAR), who have a physics-based model of the upper atmosphere. My system will combine this model with the University of Bath's Multi-Instrument Data Analysis System (MIDAS), which is software for tomographic imaging of the ionosphere using Global Positioning System (GPS) rays and other observations. When I found that the model I was originally given was unsuitable and not user-friendly, I used an interview-based study to identify the NCAR model as being suitable for my project. I have also collaborated with a group in Peru to develop a new technique for the assimilation of observations from other instruments.