MANILA - Tropical depression "Isang" has maintained its strength as it traverses the Philippine Sea Sunday, according to state weather bureau PAGASA.
PAGASA spotted Isang at 715 kilometers east of Basco, Batanes. It has maximum sustained winds of 55 kilometers per hour with gustiness of 65 kilometers per hour.
It is forecast to move west northwest at the speed of 19 kilometers per hour, said PAGASA. Isang is expected to intensify into a tropical storm in 24 to 36 hours.
Tropical Cyclone Warning Signal No. 1 is currently raised over the Batanes and Babuyan group of islands.