THURSDAY’S downpour was caused by a low pressure area and took place during a “monsoon break” or spell of hot weather, said government weather experts.
The volume of rain was also unusual.
While the month of August has normal rainfall of 143.55 millimeters, two days before the month ended this year, Pagasa already recorded 190 millimeters of rain.
The high rainfall on Aug. 28-29 alone, Thursday to Friday, measured 61.1 millilmeters, said weather specialist Jhomer Eclarino of Pagasa Mactan.
The rains started at 3:35 p.m. of Thursday, Aug. 28 and lasted until 3 a.m. the next day with breaks of 40 to 50 minutes.
The heaviest downpour was recorded between 4 p.m. to 6 p.m. Thursday, when street floods tied up traffic in lowlying areas of Cebu and Mandaue cities.
Though Pagasa is still studying the threshold of Metro Cebu, the weather station noted that streets would get flooded once rainfall reaches 30 millimeters.
Thursday wasn’t the heaviest day of rain this month which falls in the rainy reason.
Pagasa Mactan recorded 70.5 millimeters for only three hours of rain on August 20, a Wednesday, the highest level in August.
Alfredo Quiblat Jr., chief of Pagasa Mactan weather station, said a monsoon break is a natural weather phenomenon that usually lasts for two weeks.
It’s not related to an El Nino.
The heavy rains in Central and Western Visayas was caused by a low pressure area that cooled the ocean surface.
“There is now 60 percent chance of El Nino later this year because recently there is a cool and neutral ocean surface temperature,” he told CDN.
He said the country will continue to experience rains until October.
Two to three storms a month are forecast until the end of the year.
Isolated rains and thunderstorms are expected every now and then even without the presence of a weather disturbance, he said.
By October, the weather is expected to shift to the northeast monsoon or “hanging amihan” which brings cool winds usually identified with the Christmas season.
Rains will continue in most parts of the country even as the low pressure area moved away from the Philippines.
The LPA was last observed 140 kilometers north of Puerto Princesa City.
Quiblat of the Pagasa Mactan observed that the downpour last Thursday brought a large volume of rain.
He said 20 millimeters of rain accumulated in less than an hour when heavy rain feel 4:20 p.m. to 5:10 p.m.
“The average rainfall is 7.5 millimeters per hour,” he said.
“That is why it is very natural that there was flooding,” he told CDN.
In Colon Street, a 15 millimeter rainfall would cause urban flooding.
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