LARGE parts of Luzon and the Visayas remain vulnerable to heavy rain from a shear line and the northeast monsoon, the state weather bureau said on Sunday.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said rainfall will be driven by a shear line, which is expected to bring cloudy skies, scattered rains and thunderstorms over Southern Luzon and portions of the Visayas.

Northern Luzon will continue to see intermittent rain due to the northeast monsoon, locally known as amihan.

Metro Manila, Mimaropa, the Bicol Region, Quezon, Laguna, Rizal, Cagayan Valley and the Cordillera Administrative Region are among the areas forecast to experience rain.

PAGASA warned that rainfall of 50 to 100 millimeters may fall over Quezon, Camarines Norte, Camarines Sur, Albay, Sorsogon, Catanduanes and Oriental Mindoro, levels that could trigger localized flooding in low-lying and urban areas.

Similar rainfall amounts are forecast to persist on Monday across parts of Bicol and Eastern Visayas, including Northern and Eastern Samar.

The agency also issued gale warnings over northern coastal waters, including Batanes, the Babuyan Islands, Ilocos Norte and Ilocos Sur, advising small sea vessels to remain in port as seas may become rough to very rough. — Chloe Mari A. Hufana