Tropical storm "Isang" (international name "Omais") is expected to leave the Philippine area of responsibility (PAR) on Sunday afternoon or evening, Aug. 22, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said on Saturday, Aug. 21.
In the PAGASA's 5 a.m. bulletin, tropical storm Isang has started to move north-northwest over the Philippine Sea east of extreme northern Luzon.
Its location was estimated at 790 kilometers (km) east-northeast of Calayan, Cagayan or 725 km east of Basco, Batanes at around 4 a.m.
PAGASA said Isang has maximum sustained winds of 65 kilometers per hour (kph) near the center and gustiness of up to 80 kph while moving north-northwest at 15 kph.
Isang may continue to intensify until Saturday evening, Aug. 21, or Sunday morning, when it is likely to reach its peak intensity.
However, the tropical storm is still not expected to have a direct effect on the country's weather until it leaves the PAR on Sunday.
"Isang will remain far from the Philippine landmass throughout the forecast period. The tropical storm is forecast to move generally northwestward or north-northwestward today (Saturday) through tomorrow (Sunday), turn north-northwestward on Monday (Aug. 23) over the East China Sea, then northward and north-northeastward on Monday (Aug. 24)," PAGASA said.
In the next 24 hours, the easterlies or the warm winds coming from the Pacific Ocean will be the dominant weather system across the country.
Metro Manila and the rest of the country will experience partly cloudy to cloudy conditions with a high chance of isolated rain showers or thunderstorms in the afternoon or evening.
PAGASA warned the public against flash floods or landslides that may occur during severe thunderstorms, which are often associated with bursts of heavy rainfall, lightning, thunder, gusty winds, and sometimes hail.