Tropical Storm Wipha enhances southwest monsoon, triggers flooding across Luzon, Philippines

Tropical Storm Wipha remained a significant hazard over northern Luzon on July 18, enhancing the southwest monsoon and producing widespread rainfall across Metro Manila, Central Luzon, and Northern Luzon.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) placed Batanes, Cagayan including the Babuyan Islands, Apayao, Ilocos Norte, and parts of Isabela under Tropical Cyclone Wind Signal No. 2.

As of 18:00 UTC on July 18, the center of Tropical Cyclone Wipha was located over the coastal waters of Calayan, Cagayan. The system had maximum sustained winds of 85 km/h (53 mph) near the center and gusts up to 115 km/h (72 mph). It was moving northwestward at 15 km/h (9 mph).

PAGASA issued Orange rainfall warnings for Zambales and Bataan, indicating imminent flood risk, while Yellow warnings were raised for Metro Manila, Bulacan, Pampanga, Tarlac, Cavite, Batangas, and Rizal.

Heavy rainfall associated with the southwest monsoon (habagat), enhanced by Wipha, triggered riverine flooding across parts of Negros Occidental on July 17 and 18. One of the most affected areas was Barangay Camugao in Kabankalan City, where the Hilabangan River overflowed its banks, inundating multiple residential zones and commercial areas including the Riverside Café vicinity.

According to local disaster response units, at least 458 families, comprising 1 629 individuals, were evacuated to designated shelters as a result of rising floodwaters. No casualties were reported as of July 18, though damage assessments are ongoing.

The Hilabangan River, also referred to locally as the Ilog-Hilabangan, drains one of the largest basins in Negros Occidental. Provincial officials and hydrologists noted ongoing vulnerability due to the watershed’s diminished vegetative cover and upstream land degradation.

These conditions have led to recurrent flood events during enhanced monsoon periods, with short-term peaks overwhelming riverbanks and submerging low-lying barangays.

In Cebu City, Gaisano Main Mall experienced its first confirmed structural flooding on July 16, it saw indoor corridors submerged after several hours of torrential rainfall. Retail operations were disrupted and cleanup efforts mobilized within hours.

Sea conditions remained dangerous throughout the Luzon Strait and northern Philippine Sea. Waves of 4.5–6 m (15–20 feet) were recorded, prompting the suspension of sea travel across affected ports in Northern Luzon. Mariners were advised to remain in port or seek shelter.

Tropical Storm Wipha is expected to exit the Philippine Area of Responsibility by July 19, continuing into the South China Sea. The system may intensify into a Severe Tropical Storm by July 20, according to PAGASA forecasts.

JTWC forecast track takes it near or over Hong Kong around 12:00 UTC on July 20, along the coast of southern China and into northern Vietnam on July 21.

Reet Kaur

I’m a science journalist and researcher at The Watchers, contributing to the Epicenter edition, where I cover peer-reviewed scientific research and emerging discoveries across Earth and space sciences. With a background in astronomy and a passion for environmental science, I’ve worked in shark and coral conservation in Fiji, conducting reef and shark-behavior research, contributing to mangrove restoration, and earning PADI Open Water and Coral Reef Certifications. I bring a blend of scientific rigor and storytelling to illuminate the discoveries shaping our planet and beyond.

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