The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) warned on Wednesday, Dec. 25 that heavy rains may continue to affect Northern Samar and parts of Southern Luzon, including Metro Manila, due to the shear line.
The shear line is a weather system that forms when the cold winds from the northeast monsoon (amihan) collide with the warm winds from the Pacific Ocean (easterlies).
PAGASA Weather Specialist Aldczar Aurelio said heavy to intense rainfall (100 to 200 millimeters) will continue to affect Aurora, Quezon, Camarines Norte, Camarines Sur, and Catanduanes on Wednesday.
Meanwhile, moderate to heavy rainfall (50 to 100 millimeters) may persist in Metro Manila, Bulacan, Cavite, Laguna, Batangas, Rizal, Albay, Sorsogon, Masbate, Marinduque, Romblon, Oriental Mindoro, and Northern Samar.
On Thursday, Dec. 26, heavy to intense rainfall will affect only Aurora and Quezon, while moderate to heavy rains may continue in Cagayan, Isabela, Camarines Norte, and Camarines Sur.
On Friday, Dec. 27, only Cagayan and Isabela will experience heavy to intense rainfall, while Apayao and Aurora will have moderate and heavy precipitation.
PAGASA warned that flash floods and landslides could occur in areas affected by the shear line.
Over the next two days, the rest of the archipelago will experience partly cloudy to cloudy skies with localized rain showers or thunderstorms.
Aurelio also noted that, as of Wednesday, there were no low-pressure areas or tropical cyclones within or near the Philippine area of responsibility.