By Ma. Cristina Arayata
MANILA – Thunderstorms caused the phenomenal rainfall in Quezon City on Aug. 30, not the southwest monsoon (habagat), the weather bureau said Monday.
“It was due to a thunderstorm because the rain was limited to Quezon City and some surrounding areas like Marikina,” Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) Administrator Nathaniel Servando told the Philippine News Agency.
Severe thunderstorm affected the northern portion of Metro Manila between 1 and 4 p.m. on Saturday.
PAGASA’s Science Garden Station in Quezon City recorded 132.2 millimeters (mm) of rainfall, equivalent to almost a week’s worth of rain based on the monthly average of 568.5 mm.
The volume surpassed the rainfall produced by Tropical Storm Ondoy hit the country on Sept. 26, 2009.
For comparison, Servando said that when Ondoy struck, PAGASA recorded 455 mm of rain in Metro Manila in six hours.
On the other hand, 96.6 mm of rain was recorded in the Science Garden in between 2 p.m. and 3 p.m. on Saturday.
The heavy downpour caused flooding in several areas of Quezon City, including Visayas Avenue and Elliptical Road in Diliman which are rarely inundated.
Such phenomenal rainfall was likely to occur once every 15 years based on statistics and historical data, Servando said, citing the Rainfall Intensity and Duration Frequency (RIDF) analysis.
He said PAGASA issued a thunderstorm advisory for Quezon City at 11:30 a.m. and thunderstorms started at 1 p.m.
Possible in other areas
Other parts of the country could possibly experience the phenomenal rainfall, even with higher intensity, due to habagat and especially during the passage of a tropical cyclone.
Servando, however, clarified that this does not mean the phenomenal rainfall could be experienced anytime soon.
The occurrence, he said, would depend and would vary depending on the RIDF data from PAGASA stations across the country.
“It’s hard to forecast the thunderstorm occurrence in a specific area, when it will happen and the intensity,” Servando said.
He assured PAGASA has radars that can monitor thunderstorm formation as well as the areas that could be affected. This results in the issuance of thunderstorm watch and advisories.
PAGASA also issues color-coded (yellow, orange and red) rainfall warnings, Servando said. (PNA)
