MANILA, Philippines - The red warning signal for heavy rainfall was re-issued in Metro Manila Wednesday afternoon due to heavy rains caused by a series of thunderstorms from the southwest monsoon.
Metro Manila was placed under red signal for 30 consecutive hours, from 9 p.m. on August 6 to 3 a.m. on August 8, due to torrential monsoon rains.
The rainfall signal was terminated briefly at noon, but yellow and green warnings were subsequently re-issued by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) at around 1 p.m.
Red signal in Metro Manila was issued anew at around 4 p.m. of Wednesday due to continuous heavy rains.
The heavy rainfall warning system is divided into three levels, using color codes, yellow (Advisory), green (Alert), and red (Emergency).
Red warning signal is the highest alert for rainfall, particularly if "rainfall observation is more than 30 mm (heavy rains) within one hour or if continuous rainfall for the past three hours is greater than 65 mm."
A green signal is for "rainfall observation of more than 15 mm to 30 mm (moderate) within one hour," while a yellow warning signal is issued when a "rainfall observation is from 7.5 mm to 15 mm (light rains) within one hour and is likely to continue.
PAGASA said the southwest monsoon has weakened slightly as typhoon "Haikui" located outside the Philippine area of responsibility (PAR) has moved farther away and made landfall in the vicinity of Shanghai, China on Wednesday morning.
Weather forecaster Buddy Javier said rainfall warning is updated every three hours.
He also noted that the amount of rainfall from 8 a.m. Tuesday to 8 a.m. Wednesday, recorded at the PAGASA Science Garden Station in Quezon City, was 391.4 millimeters (mm).
This was higher than the 24-hour rainfall from August 6 to 7 at 323.4 mm.
Likewise, the accumulated rainfall since August 1 is 906.55 mm, which is almost double the August average rainfall of 526.8 mm at the Science Garden Station.
Gine Nievares, hydrologist of the PAGASA, said four of the nine major dams in Luzon continue to release water.
She said the La Mesa Dam also continues to overflow with its water level at 80.36 meters, which is above its 80.15-meter spilling level, at 8 a.m. on Wednesday.
"The level in La Mesa Dam is gradually subsiding as of this morning," she said.
Javier said the weather condition in the Northern, Central and Southern Luzon, and Visayas, particularly the western sections will improve by Thursday.