Yutu formed as a tropical depression over the Pacific about 600 kilometers northeast of Manila on Monday, 23 July 2001. It tracked west-northwest at 25 kilometers per hour and shortly entered the Luzon Strait. Yutu intensified into a tropical storm as it crossed the Luzon Strait on that day. As Yutu moved within 800 km of Hong Kong and posed a threat to the territory, the Standby Signal No. 1 was hoisted at 9:50 p.m. on the same day. Yutu took on a more westward track after it entered the South China Sea and intensified rapidly into a typhoon during the day on 24 July. Under the influence of the outer rainbands of Yutu, the weather in Hong Kong deteriorated in the afternoon. Heavy squally showers and thunderstorms brought 10 to 30 millimeters of rainfall to the territory.
As Typhoon Yutu came closer to the coast of Guangdong, the Observatory hoisted the Tropical Cyclone Signal No.3 at 3:50 p.m. on 24 July. Winds locally strengthened and became strong offshore around 10 p.m. on that day. During the few hours before midnight, Yutu intensified rapidly and maximum winds near its center strengthened from 120 to 150 kilometers per hour with gales affecting areas up to 160 km from its centre. As Yutu posed a serious threat to Hong Kong, the Observatory hoisted the No. 8 Northeast Gale or Storm Signal at 0:30 a.m. on 25 July. Winds strengthened quickly to gale force offshore and on high grounds in the early morning of 25 July. Heavy squally showers associated with Yutu brought more than 20 millimetres of rainfall to most parts of the territory, and areas around Tsuen Wan recorded more than 60 millimetres of rainfall.
Yutu slowed down during the day on 25 July. It passed about 180 kilometers to the south of Hong Kong around noon. As wind changed from northeasterly to southeasterly, the No.8 Northeast Gale or Storm Signal was replaced by the No.8 Southeast Gale or Storm Signal at 10:40 a.m. Gale force winds affected mainly the southern part of the territory, including Cheung Chau, and high grounds throughout the afternoon.
Winds began to weaken in the evening as Yutu moved away from the territory, and the No.8 Southeast Gale or Storm Signal was replaced by the No. 3 Strong Wind Signal at 7:40 p.m. on 25 July.
For the latest weather forecast, please refer to the following web sites:
http://www.weather.gov.hk/wxinfo/currwx/flw.htm (local weather forecast), and
http://www.weather.gov.hk/wxinfo/currwx/f5d.htm (5-day forecast).