Dr. Flaviana Hilario, head of research and development at the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa), said the rainfall warning system would initially be tested in Metro Manila and would be ready by June, the start of the rainy season.
The Philippines currently has no warning mechanism for rainfall. What it has is a four-level warning signal for tropical cyclones.
The typhoon warning system measures the wind strength of an incoming typhoon, while the rainfall warning system would measure the amount of water that is expected to fall on a specific day and place, Hilario said.
The alert system for rainfall would enable communities to plan ahead and better anticipate flash floods and river overspills even if there is no typhoon in sight, Hilario said.
For average days, rainfall alerts could help residents plan their day’s activities.
Pagasa Administrator Nathaniel Servando said the rainfall alert system should be ready by June, the start of the wet season in the Philippines.
“We have seen that the rains have become damaging even if there is no typhoon. This is one of the considerations here,” Servando said.
He said Pagasa was studying the rain alert system used by the Hong Kong Observatory, which has three alert levels that correspond to a certain amount of rain.
This is more detailed that the usual forecast of light, moderate or heavy rains.
In the case of typhoons, the agency would also be able to gauge the expected downpour, which is measured in millimeters per hour.
Aside from the amount of rainfall that clouds carry, Servando said they would also like the rainfall alert information to include data such as the probability of precipitation, possible hazards, areas affected, and estimated amount of rain in the next few hours.