Manila: Three weather systems are set to continue affecting various regions of the Philippines, leading to widespread rain, as reported by the country's weather bureau on Monday. According to Philippines News Agency, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) issued a 4 a.m. advisory highlighting that areas including Isabela, Quirino, Nueva Vizcaya, Kalinga, Mountain Province, Ifugao, Aurora, Nueva Ecija, Bulacan, Rizal, and Quezon are expected to experience cloudy skies with scattered rains and isolated thunderstorms due to the shear line. Easterlies are predicted to cause scattered rains and thunderstorms over the Visayas, Mimaropa, Bicol Region, Dinagat Islands, and Surigao del Norte. The northeast monsoon, locally known as "amihan," is anticipated to bring rainy weather to Ilocos Norte, the rest of Cagayan Valley, and the rest of the Cordillera Administrative Region. Metro Manila along with the rest of Central Luzon will likely encounter isolated rain sho wers or thunderstorms due to the shear line, while isolated rains in the Ilocos Region are attributed to the "amihan." Other parts of the country are expected to see isolated rain showers or thunderstorms as a result of easterlies. Extreme Northern Luzon is forecasted to experience strong to gale-force northeast winds, resulting in rough to very rough sea conditions. Meanwhile, Central Luzon and the rest of Northern Luzon will be subject to moderate to strong northeast winds and moderate to rough coastal waters. The remaining areas of the archipelago can expect light to moderate east to northeast winds and slight to moderate sea conditions.