The weather bureau warns of the rapid hike of water level in Greater Manila.
Philippine Atmospheric, Geophysical, and Astronomical Services Administration (Pagasa) once again warns of the possible flash floods and landslide that the Southwest monsoon may cause.
Pagasa’s warning was particularly addressed to the provinces of Zambales, Bataan, Pampanga, Pangasinan, Nueva Ecija, Tarlac, Bulacan, Rizal, Cavite, Laguna, Batangas and even Metro Manila.
The national weather bureau said that the heavy rains being experienced in the aforementioned provinces are brought about by the Southwest monsoon because of the low pressure area (LPA).
Aside from Luzon, the LPA and the monsoon also affects the Ilocos Region, Cordillera Administrative Region (CAR), the rest of Central Luzon, MIMAROPA and Western Visayas region.
In its latest weather bulletin, Pagasa stated that cloudy skies with light to moderate rains and thunderstorms will be experienced over the rest of Luzon and Visayas while partly cloudy to cloudy skies with isolated rainshowers or thunderstorms is expected over Mindanao.
It added that moderate to strong winds blowing from the Southwest will prevail throughout the archipelago and the coastal waters will be moderate to rough.
Wikipedia explains a low-pressure area, low or depression, as a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. The formation process of a low-pressure area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas. The first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies (a trough with large wavelength that extends through the troposphere). A second area of wind divergence aloft occurs ahead of embedded shortwave troughs, which are of smaller wavelength.
Diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity.