By Ellalyn de Vera-Ruiz
Late afternoon thunderstorms brought sudden heavy rains over Metro Manila on Thursday, leaving motorists and commuters stuck in traffic and stranded in floods.
According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), sudden heavy rains and thunderstorms are more frequent during the southwest monsoon or “habagat” season.
Thunderstorm activity is at its peak in the late afternoon or early evening due to high relative humidity.
PAGASA defined relative humidity as “the ratio of the actual vapor pressure to the vapor pressure corresponding to saturation at the prevailing temperature.” It is simply the percentage of saturation or moisture in the air.
Thunderstorms are manifested by gusty winds and strong rains that last about an hour, which cause flooding especially in low-lying areas.
It is often associated with localized or isolated heavy rains or sometimes hail.
Earlier, PAGASA advised the public that there is a higher chance of thunderstorms and rain showers over most parts of the country due to the prevailing southwest monsoon.