Hong Kong raised the standby typhoon signal No 1 on Friday as Typhoon Krosa moved across the South China Sea. Krosa entered the South China Sea on Friday morning and tracked westward steadily. It became the first storm to prompt Hong Kong to raise a cyclone warning in November since 2006. The city has issued only three cyclone alerts in the month over the past 30 years. Winds will strengthen and there will be rains along South China coasts Cheung Yuen-chung, HK Observatory The Hong Kong Observatory said Krosa would bring strong winds and squally rains to Hong Kong over the weekend when it was expected to be closest. “Winds will strengthen and there will be rains along South China coasts,” senior scientific officer Cheung Yuen-chung said. At 4 pm, Typhoon Krosa was estimated to be about 530 kilometres southeast of Hong Kong. It is forecast to move west or west-northwest at about 16 kilometres per hour crossing the northern part of the South China Sea. According to the present forecast track, Krosa would keep its distance from Hong Kong on Friday with the chance of a strong wind signal No 3 being raised during the day seen as not high, the observatory said. But a replenishment of a northeast monsoon was also expected to reach the city on Saturday, making the weather unstable, it said. Krosa intensified from a tropical storm on Wednesday into a typhoon with winds of up to 120 kilometres per hour. Hong Kong’s tropical cyclone season is normally only in the summer. Observatory records show that the city had raised only three tropical cyclone warnings in November over the past 30 years. The latest was in 2006, and before that in 1993 and 2000. This year so far, Hong Kong has been affected by six tropical cyclones – including two super typhoons Usagi in September and Utor in August. Video: How typhoons are formed HK Observatory tracking map of Krosa .