A low pressure area (LPA) being monitored outside the Philippine Area of Responsibility (PAR) is unlikely to develop into a tropical depression within the next 24 hours, the state weather bureau said Saturday.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said LPA 08e was being monitored as of 2 a.m. August 15 and remains outside the PAR.

Meanwhile, PAGASA warned of heavy rainfall due to the southwest monsoon, or habagat, in parts of Luzon.

Zambales and Bataan may receive 50 to 100 millimeters of rain Saturday and Sunday, while Ilocos Sur, La Union, Benguet, Pangasinan, Zambales, Bataan and Occidental Mindoro are expected to experience the same amount of rainfall Monday.

PAGASA said rainfall may be higher in mountainous and elevated areas, while significant rainfall in previous days could worsen the impacts in some areas.

Disaster risk reduction and management offices in affected areas were advised to take necessary measures to protect lives and property.

PAGASA's regional offices may also issue heavy rainfall warnings, thunderstorm advisories and other severe weather information as conditions warrant.

The weather bureau urged the public to continue monitoring its updates.

Unless significant changes occur, PAGASA said its next weather advisory will be issued at 11 a.m. Saturday.