Currently in Japan and flying to HND on domestic flight tomorrow (Sun,. Sept. 8th). I just watched evening news and forecast is that this one will pass Tokyo area fast.
Typhoon no. 15 (in Japan they call it by number, not by name) current forecast is that Tokyo will start experience effect of Typhoon around 3 p.m. on Sunday and last till 9 a.m. on Monday. If your departure or arrival into HND or NRT is between Sunday 3 p.m. and Monday 9 a.m. then will be facing likely cancellation/delay.
My flight is on Sunday noon time so hope my flight will go, fingers crossed...