ITER-grade tungsten and dispersoid-strengthened tungsten samples with the top surface angled at ~15 deg toward the incident plasma flux were exposed to nine H-mode discharges with edge-localized modes (ELMs) in the lower divertor of the DIII-D tokamak using the Divertor Materials Evaluation System (DiMES). Surface damage included cracking and flaking of material on the two samples farthest away from the plasma strike point (SP) and significant melting of the two samples closest to the SP. Heat flux and thermal analysis tools new to DIII-D have been applied to better understand this material response and to help optimize the exposure conditions for future experiments. SMITER field-line tracing simulations based on IRTV data and EFIT equilibria estimate an average inter-ELM perpendicular heat flux on the angled surfaces of 10.1 to 19.6 MW/m2 for a majority of the nine discharges, increasing to 15.6 to 24.5 MW/m2 for the single, higher-power shot where samples melted. Fast camera data showed shallow intra-ELM melting and resolidification, which transitioned to bulk inter-ELM melting with melt motion in the direction. About 50% of the protruding volume of the most affected sample was displaced via melt motion. SIERRA thermal modeling software was able to reproduce an onset time of melting consistent with fast camera data and final sample conditions, within <200 ms. Maximum surface temperatures of 3122 and 2787 K are estimated for the samples farthest away from the SP, while the closest samples achieve melting at 4067 and 4750 ms into the ~5000-ms plasma exposure. A +10% increase in both the SMITER calculations and the estimated ELM heat loads was required to achieve this result, which is within the uncertainty of the diagnostic data but likely accounts for non-ideal geometry effects plus other physics uncertainties not included in this first iteration of modeling. This work provided valuable estimates of the three-dimensional temperature evolution to help better understand the observed surface morphology and internal recrystallization of samples, which are discussed in detail in a complementary paper (R. D. Kolasinski et al. “Recrystallization, Melting, and Erosion of Dispersoid-Strengthened Tungsten Materials During Exposure to Divertor Plasmas”). Benchmarking efforts with more diagnosed DIII-D experiments are underway to further refine the SMITER and SIERRA models for DiMES. Future use of these tools will enable researchers to precisely target heat flux exposure conditions in DIII-D to test—but not exceed—the thermomechanical limitations of novel plasma-facing materials.