Parts of Metro Manila and several areas in Luzon will experience moderate to heavy rain, lightning and strong winds on Sunday morning, the state weather bureau said.
The Philippine Atmospheric, Geophysical and Astronomical Services Administration issued a thunderstorm advisory at 7:10 a.m., warning that the conditions could affect additional locations within the next two hours.
In Metro Manila, Marikina, Navotas, Malabon, Valenzuela and Caloocan were placed under the advisory.
Pagasa also identified Subic, Castillejos, Olongapo, San Narciso, San Felipe and San Marcelino in Zambales as areas likely to experience thunderstorms.
Bagac in Bataan is likewise included in the warning.
The same weather conditions were already occurring in Quezon City, Cabangan and San Antonio in Zambales, and Morong in Bataan, and could continue for up to two hours.
Pagasa advised residents to remain alert for possible flash floods and landslides, particularly in flood-prone and elevated areas.
The southwest monsoon was also expected to bring cloudy skies with scattered rains over the Ilocos Region, Bataan and Zambales, while the rest of Luzon, the Visayas and Mindanao could experience generally fair weather with isolated thunderstorms.