13 as the system continued to organize. Four hours later, the JTWC issued its first warning on the newly upgraded tropical depression. It was upgraded to Tropical Storm Yancy at 12:00 UTC August 14 based on increased curvature of convection and consolidation of the cyclonic center, though the JMA assessed this upgrade twelve hours sooner. Beyond August 13, Yancy continued to follow a westward track, but it did so at a quicker pace. This period of rapid movement lasted for two days as the storm moved under the influence of an intensifying subtropical ridge to the north. At 12:00 UTC on August 16, the JTWC determined that Yancy had strengthened into a typhoon. Yancy's trajectory shifted from westward to north-northwestward after the subtropical ridge weakened in response to a shortwave trough moving off the coast of China. The typhoon continued to move in this direction for eighteen hours; beyond this point, the subtropical ridge re-strengthened and Yancy continued its westward trajectory. According to JTWC data, Yancy intensified into the equivalent of a Category 2 on the Saffir–Simpson scale at 18:00 UTC on August 17, peaking in intensity six hours later with one-minute sustained winds of 90 knots (165 km/h; 105 mph). JMA data, however, placed Yancy's peak intensity eighteen hours later, with ten-minute sustained winds of 80 knots (150 km/h; 90 mph) and a minimum barometric pressure of 28.05 inHg (950 mbar). On August 18, just as the cyclone was peaking in intensity, it developed an eye. Yancy then proceeded to carry out a trochoidal oscillation, tracking across Taiwan the next day. Yancy's interaction with mountainous terrain on the island, and later the Chinese mainland, caused it to weaken. JMA data reflects this weakening, with Yancy's winds decreasing to severe tropical storm intensity at 18:00 UTC August 19 and tropical storm intensity twelve hours later. The JTWC downgraded Yancy to a tropical storm at 00:00 UTC August 20; thirty hours later, the agency downgraded the storm to a tropical depression, simultaneously issuing its final warning and declaring Yancy dissipated. The JMA similarly found that Yancy had weakened to a tropical depression on August 22, and it stopped tracking the system the next day. Impacts In the Philippines where Yancy was known by the PAGASA name "Gading",, a monsoon surge triggered by the storm resulted in significant rainfall which flooded areas across northern Luzon. Over 60,000 residents fled to evacuation centers.