How Porter’s 5 Force model might contribute to a SWOT ysis?

Porter's 5 has to do with a firm's environment. (That's why its called the "Five Forces" since it operates on the firm's external condition). Strengths, Weaknesses, Opportunities & Threats are basically the internal and external condition of a company. So, Opportunities and Threats can be looked at via Porter's Five Force Model, which is what Porter suggests in his book in 1980 on the model.