A stationary frontal system and the Intertropical Convergence Zone (ITCZ) are bringing moderate to heavy rains across extreme northern Luzon and southern Mindanao, state weather bureau meteorologists said Sunday.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said the frontal system is affecting the Batanes and Babuyan Islands, bringing overcast skies and scattered rain showers. Weather conditions in the country’s northernmost islands are expected to improve by Monday.

In the south, the ITCZ is generating scattered rain showers and thunderstorms over the Zamboanga Peninsula, Sultan Kudarat, Sarangani, Lanao del Sur, Maguindanao del Norte, Basilan and Tawi-Tawi.

Meanwhile, localized thunderstorms and easterlies are affecting Metro Manila and the rest of the country, bringing partly cloudy to cloudy skies with isolated afternoon or evening rain showers.

With active rain-bearing systems affecting several areas, PAGASA weather specialist Veronica Torres urged the public to remain cautious of possible flooding and landslides.

The weather bureau warned that the combined effects of the frontal system, ITCZ and severe localized thunderstorms could still trigger moderate to heavy rains, particularly in vulnerable areas.

Despite the rains, PAGASA also warned of dangerous heat index levels nationwide.

Dipolog is forecast to record a peak heat index of 46 degrees Celsius on Sunday, while Metro Manila is expected to experience heat indices ranging from 41 degrees Celsius to 44 degrees Celsius.