CityScaleCast: Spatiotemporal GNN for City-Scale Weather Prediction with GraphCast-Guided Parallel Modeling and Multi-Step Forecasting in Sendai. - Xuanwen Pan; Yoichi Shimomura; Sichen Tao; Masatoshi Kawai; Keichi Takahashi; Hiroyuki Takizawa (SCA/HPC Asia Workshops, 2026)