From https://www.metoc.navy.mil/jtwc/products/wp0223prog.txt

DUE TO THE COMPETING STEERING PATTERN AFTER TAU 72, THERE IS INCREASING UNCERTAINTY IN THE EXTENDED FORECAST TRACK WITH A SIGNIFICANT DECREASE IN TRACK SPEEDS AND POSSIBLE QUASI-STATIONARY MOTION LIKELY EAST OF TAIWAN. THIS SCENARIO IS REFLECTED IN THE WIDE SPREAD OF SOLUTIONS IN THE ECMWF ENSEMBLE. THE 260000Z GFS ENSEMBLE INDICATES GREATER UNCERTAINTY AFTER DAY 5 WITH A BIFURCATION IN PROBABILISTIC GUIDANCE; HALF THE SOLUTIONS TRACK THE SYSTEM OVER TAIWAN AND INTO THE NORTHERN SOUTH CHINA SEA WHILE THE OTHER HALF RECURVE THE SYSTEM NORTHEASTWARD. ALTHOUGH BEYOND THE SCOPE OF THIS FORECAST, THE LARGE DEGREE OF UNCERTAINTY AND POTENTIAL FOR ERRATIC MOTION WILL HAVE TO BEMONITORED CLOSELY.

The bolded bit would be particularly bad for flights out of Japan in the coming 10-14 days.