Wind energy, a rapidly expanding clean energy source, faces significant challenges posed by lightning strikes that jeopardize the safe and reliable operation of wind farms. Contrary to conventional strike distance models that overlook the dynamics of upward leader development, the unique characteristics of wind turbines as rapidly rotating, elevated structures necessitate a more pragmatic approach that incorporates the guiding role of upward leaders in the lightning strike process. The traditional stable inception criterion for upward leader relies heavily on iterative computations to track leader progression, introducing substantial computational burdens that hinder practical applicability. This paper presents a model for upward leader development, specifically tailored to the context of wind turbine blades. The model computes the length of the initial streamer region and the initial charge associated with the upward leader, providing insights into the initiation phase of the lightning strike. Furthermore, it systematically examines the influence of various parameters on both the initial streamer region length and initial charge. Ultimately, a simplified stable inception criterion for upward leader is introduced, which contributes to facilitating the development of more efficient and cost-effective protection strategies.