WHILE the ridge or extension of the high pressure area (HPA) is affecting Northern Luzon, overcast skies and isolated rain showers, as well as thunderstorms may prevail over large parts of the country, the state-run weather agency said on Wednesday.

An opposite of the low pressure area (LPA), HPA indicates where the atmospheric pressure is higher than its surroundings and formation of clouds is usually suppressed, thus, less chance of rains, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa).