MANILA – The southwest monsoon (habagat) is affecting the western section of Northern Luzon, while localized thunderstorms are expected to bring isolated rainshowers over the rest of the country, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said Saturday. In its 4 a.m. public weather forecast, PAGASA said the Ilocos Region, Apayao, Abra, Batanes,…