MANILA - Weather bureau PAGASA spotted a low pressure area (LPA) about 335 km northeast of Hinatuan, Surigao del Sur at 4:00 AM Sunday.
PAGASA said serious flooding is expected in low-lying areas and landslides in mountainous areas of Eastern Samar, Samar, Leyte, Southern Leyte, and Biliran Island as of 7:30 AM.
The weather bureau advises the public and the concerned disaster officials to monitor weather conditions and watch for the next advisory to be issued at 10:30 AM.
The LPA is expected to bring cloudy skies with moderate to occasionally heavy rains and thunderstorms which may trigger flashfloods and landslides over Eastern and Central Visayas and the Caraga regions.
The weather bureau said the LPA may intensify into a storm within the next 2-3 days.
Meanwhile the southwest monsoon or "habagat" is affecting the western section of Luzon and of Visayas.
PAGASA is forecasting light to moderate rains and thunderstorms over Metro Manila, the rest of Visayas, the regions of Ilocos, MIMAROPA, Zamboanga Peninsula, Northern Mindanao, Davao and over the provinces of Zambales and Bataan.
Partly cloudy to cloudy skies with rainshowers or thunderstorms will prevail the rest of the country.
Meanwhile tropical storm Roke (Fabian) has been spotted 385 km west of Sinait, Ilocos Sur and is already out of the Philippine area of responsibility (PAR).
But PAGASA is monitoring another weather system, tropical storm Naru, which is still 3,160 km east northeast of Basco, Batanes or outside PAR.