By Alexandria Dennise San Juan
Cloudy skies with isolated rain showers or thunderstorms will prevail across the country this weekend due to easterlies and the southwesterly windflow, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said.
In its latest weather update issued on Friday, PAGASA said that flash floods or landslides are possible in areas affected by the two weather systems during severe thunderstorms.
According to PAGASA Weather Specialist Samuel Duran, the southwestern windflow will affect extreme Northern Luzon particularly Batanes and Babuyan Islands, bringing partly cloudy to cloudy skies with isolated rain showers or thunderstorms.
The same weather condition is also expected over Metro Manila and the rest of the country caused by easterlies, or warm winds from the Pacific Ocean, and localized thunderstorms.
PAGASA earlier noted that the southwesterly surface wind flow is a manifestation of the arrival of southwest monsoon, locally called "habagat," which is associated with the rainy season in the coming days.
Aside from this, the bureau also monitors other indicators of the coming rainy season, adding that the prevalence of frontal system and frequent thunderstorms in the afternoon or evening are manifestations that the wet season is starting soon.
Dangerous temperature levels
Despite this, dangerous levels of heat indices were recorded in different parts of the country on Thursday, the highest was in Legazpi City, Albay at 46 degrees Celsius (°C), followed by the 45 °C at PAGASA's CLSU Station in Munoz, Nueva Ecija.
The heat index, PAGASA explained, refers to the actual feel of temperature, as opposed to the temperature measured by a thermometer. The high air temperatures and high relative humidity are the factors considered in heat index which give high apparent temperatures or indices.
The state weather bureau considered heat indices of 41°C to 54°C as "dangerous," meaning heat cramps and heat exhaustion are likely, and a heat stroke is probable with continued activity.
In Metro Manila, other cities also experienced dangerous levels of heat index with 42 °C in Port Area, Manila and at the NAIA Station in Pasay City, and 41 °C in Science Garden, Quezon City.
Dangerous levels of temperature were also recorded in Tuguegarao City, Cagayan at 44 °C; Calapan, Oriental Mindoro; Maasin, Southern Leyte; and Sangley Point, Cavite, at 43 °C; Ambulong, Batangas; Aparri, Cagayan; Casiguran, Aurora; and Cotabato City, Maguindanao at 42 °C; and Catbalogan, Western Samar; Coron, Palawan; Cuyo, Palawan; Davao City, Davao Del Sur; Laoag City, Ilocos Norte; Puerto Princesa City, Palawan; and San Jose, Occidental Mindoro at 41 °C.
Based on the data from PAGASA, San Jose City in Occidental Mindoro has recorded this year's highest heat index so far in the country with a sizzling 58 °C observed last April 20, followed by the 53 °C in Butuan City, Agusan Del Norte on May 6.
The state weather agency advised the public to stay indoors as much as possible, wear lightweight and light-colored clothing, and to drink plenty of water regularly.