(UPDATE) THE weather bureau warned of dangerous heat index levels in 19 areas across the country on Saturday.Based on the Philippine Atmospheric, Geophysical and Astronomical Services Administration's (Pagasa) 5 p.m. forecast on Friday, the following areas may have a heat index ranging from 42 degrees Celsius to 44 C on Saturday:Dagupan City, Pangasinan – 44 CBacnotan, La Union – 42 CAparri, Cagayan – 42 CTuguegarao, Cagayan – 42 CClark Airport (DMIA), Pampanga – 42 CAmbulong, Tanauan, Batangas – 42 CCoron, Palawan – 42 CPuerto Princesa City, Palawan – 42 CAborlan, Palawan – 44 CVirac (SYNOP), Catanduanes 42 CCBSUA-Pili, Camarines Sur – 43Roxas City Capiz – 43 CIloilo City, Iloilo – 42 CDumangas, Iloilo – 43 CCatarman, Northern Samar – 44 CGuiauan, Eastern Samar – 43 CZamboanga City, Zamboanga del Sur – 43 CDavao City, Davao del Sur – 42 CCotabato City, Maguindanao – 43 CPagasa said the heat index is what the temperature feels like to the human body when relative humidity is combined with the air temperature.It advised the public to limit the time spent outdoors, especially at noon, and drink plenty of water.People going outdoors are reminded to use umbrellas or wear hats and sleeved clothing.Most parts of the country will continue to experience generally fair weather conditions and possible isolated rain showers or thunderstorms.The archipelago will have light to moderate winds and slight to moderate seas.The temperature in Metro Manila will range from 25 C to 35 C; Baguio City, 17 C to 26 C; Laoag City, 24 C to 33 C; Legazpi City, 26 C to 33 C; Metro Cebu, 27 C to 32 C; and Metro Davao, 25 C to 34 C.