The time-variable radiation deposited in the atmosphere of a planet induces variations in the thermal and chemical structure that may be detectable with current and future missions. Using EGP+ (Mayorga et al. 2021), we first look to eccentric planets to gain a holistic understanding of how the macro planet-star system properties lead to variations in atmospheric response. We explore a grid of cloudless eccentric planet model atmospheres to ascertain the dominant variables that control atmospheric response to periastron passage in a variety of cases and predict observable features indicative of their response. We explore a range of parameters including orbital period, eccentricity, stellar effective temperature, and planet gravity in an attempt to determine a diagnostic measure of the observability of spectral changes. We’ll present preliminary insights and discuss future directions to explore other stellar driven time-variable phenomena.