The same monsoon trough that spawned Typhoon Koppu also produced an area of convection to the north @-@ northeast of Guam , becoming a tropical depression on October 19 . The system moved northwestward and later turned to the northeast around the subtropical ridge . With low wind shear and favorable outflow , the convection became better organized , and the JMA upgraded it to Tropical Storm Parma on October 21 . After an eye began to form , Parma was upgraded to typhoon status the next day . An approaching trough caused Parma to accelerate northeastward while also increasing outflow . On October 24 , the JMA estimated peak winds of 175 km / h ( 110 mph ) while the JTWC estimated winds of 240 km / h ( 150 mph ) , an unusually high intensity for 30 ° N. Subsequently , Parma rounded the subtropical ridge and began moving to the east @-@ southeast , beginning a nearly week @-@ long loop . The cold front had passed to the north and failed to bring the typhoon northeastward .