Typhoon signal No. 1, issued at 10:20 pm on Friday, will remain in force in Hong Kong for most of the time on Saturday as an area of low pressure has intensified into a tropical depression off Luzon in the Philippines, says the Hong Kong Observatory.

The forecaster warned that it will remain extremely hot on Saturday with temperatures of around 35 degrees Celsius in the urban areas, and reaching 38 or 39 degrees over the northern part of the New Territories.

The circulation of the tropical depression is relatively small and is expected to maintain a distance of about 500 kilometers or above from Hong Kong during the day on Saturday, the observatory said in a 9:45 am bulletin.

ALSO READ: Observatory: HK’s August much wetter than usual

According to the current forecast, the tropical depression will intensify progressively and edge closer to the western coast of Guangdong.

“Depending on the intensity of the tropical cyclone, the distance of its strong winds from Hong Kong and the change in local wind conditions, the observatory will assess the need for issuing the Strong Wind Signal, No. 3 at first tomorrow (Sunday),” reads the bulletin.

With the tropical cyclone edging closer, local winds will strengthen gradually and the weather will become unsettled Sunday, the HKO said, adding that it will be windy with heavy squally showers and thunderstorms on Monday.

READ MORE: HKO mulls T1 signal due to low pressure in S. China Sea

Cautioning that seas will be rough with swells, it advised people to stay away from the shoreline and not to engage in water sports.

Due to storm surge, there may be flooding in low-lying coastal areas on Monday morning, it added.