As supercomputing shifts to accelerator hardware to maintain performance growth as Moore's Law withers away, GPUs take center stage for Jupyter in HPC. Jupyter has become a principal platform for GPU-powered AI and analytics application workflows built on Tensorflow, PyTorch, and RAPIDS. NERSC's first production system with a GPU partition, Perlmutter, is arriving in 2021 with "built-in" Jupyter support from the vendor. This is happening because system vendors see Jupyter as a key component of the data/AI ecosystem and are motivated to engage with HPC centers to meet user needs.