Evaluation and analysis of business processes are important for improvement of business processes. Business process modeling is used as a medium of communication between stakeholders. Most of the research in business process modeling is focused on alignment of information technology services and business operations. Existing process models lack the representation of performance data for evaluation and analysis. The process models conceived for information system development are not sufficient for such representation. This paper discusses the challenges of business process modeling in the post execution analysis context and describes the characteristics of an analytical modeling language.