Some storms are already popping up in West Tokyo. With the extreme heat of the last few days, there's a lot of energy to be released and things could get spectacular. It could also be a nothing burger.
You can monitor the situation in real time here: https://www.jma.go.jp/bosai/en_nowc/#zoom:10/lat:35.778828/lon:139.529800/colordepth:normal/elements:hrpns&slmcs&slmcs_fcst
by biwook