Metro Manila is expected to face a week of dangerous heat levels and localized thunderstorms as Easterlies from the Pacific Ocean dominate the region, state weather forecasters said Sunday.

As the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) projected, the heat index in Pasay City reach a "danger level" of 42 degrees Celsius on Sunday. Ambient temperatures across the National Capital Region are forecast to range between 25 and 36 degrees Celsius through 9 May, but high humidity will likely keep the perceived heat at hazardous levels.

PAGASA also issued a thunderstorm watch for the metropolis and surrounding provinces, warning that severe localized thunderstorms are more likely to develop within a 12-hour window. This pattern of intense morning heat followed by isolated afternoon or evening rain is expected to persist throughout the week.

Nationally, the heat index is forecast to peak at 43 degrees Celsius in areas such as Laoag City and Tuguegarao City, while the southern regions may experience scattered rains and potential flash floods.

In response to the forecast, the City of Manila has implemented several mitigation measures. Mayor Francisco "Isko Moreno" Domagoso directed the Manila City Disaster Risk Reduction and Management Department (MCDRRMD) to launch "Oplan Misty," which uses water trucks to spray a fine mist along Taft Avenue to cool public spaces. Additionally, the city has shifted municipal employees to a four-day workweek and mandated strict hydration protocols for outdoor frontliners, including traffic enforcers and police officers.

Authorities advise citizens to remain hydrated and limit outdoor activities to avoid heat-caused illnesses during the day. Taking necessary precautions to avoid heat and sun exposure was also encouraged as the "Agua de Mayo" (May rain showers) remains to arrive, according to Domagoso.