early on august 3, the japan meteorological agency (jma) upgraded an area of low pressure near wake island to a tropical depression. the system intensified rapidly and just 6 hours later, the jma upgraded the system to a tropical storm, naming it "merbok". soon, the joint typhoon warning center (jtwc) started monitoring the system as a tropical depression, and upgraded it to a tropical storm later. merbok began to move westward slowly, but soon afterwards, it turned northwest and gradually drifted in that direction. late on august 5, the jma upgraded merbok into a severe tropical storm. early on august 6, the jtwc upgraded merbok into a category 1 typhoon east-southeast of tokyo, japan. early the next day, the storm's winds reached a peak of on the sshs. later that day, the system was caught in a moderate vertical wind shear and started weakening. on august 8, the system started accelerating towards north at the speed of and was gradually diminishing because of colder and colder sea surface temperatures and unfavorable conditions. as a result, the jma reporting that the system was no longer a severe tropical storm, downgraded merbok to a tropical storm. late on that day, the system started showing extratropical characteristics as the convection near the eye dissipated rapidly. thus, the jtwc issued their final warning on the system reporting that the system was no longer tropical. later, the jma, issuing their final warning on the system, reported that the system was no longer tropical.