Severe Tropical Storm Bising—internationally known as Danas—continues to intensify as it tracks northward off the west coast of Luzon. The storm, currently packing sustained winds near 85 mph (approximately 137 kph) with a central pressure around 990 hPa, is bringing significant rainfall and gusty winds to parts of Northern Luzon and southern Taiwan.
While the storm’s center remains offshore, its broader influence extends far across the region. The key impact for the Philippines is not the eye itself, but the widespread inflow of moisture it is dragging across the archipelago. This has fueled days of torrential rain, particularly along the northwestern coastline of Luzon, and is expected to continue for several more days.
Inflow Driving Dangerous Conditions in Northern Luzon
Flooding rains have battered the mountainous areas of Ilocos Region and Cordillera Administrative Region, with significant rainfall totals recorded in provinces like Ilocos Norte, Ilocos Sur, La Union, and Benguet. Orographic lifting—where moist air is forced upward by terrain—has worsened conditions in higher elevations, with up to 300 mm of total rainfall expected in some locations over the next five days.
Mudslides have already been reported in Benguet, and localized flash floods remain a risk across the region. Areas including Baguio City, Pagudpud, Vigan, and San Fernando are likely to continue experiencing strong gusts and periods of heavy downpours through midweek.
Western coastlines such as Pangasinan, Zambales, and even parts of Metro Manila are seeing persistent showers. Even on days when morning skies appear calm, daytime heating can spark afternoon thunderstorms, adding to the rainfall totals. Conditions may slowly ease by the weekend or early next week as Bising moves farther north and begins to weaken.
Possible Upgrade to Typhoon
Satellite imagery, including recent microwave scans, suggests that Bising is organizing further, with indications of an eyewall developing. Though still classified as a severe tropical storm by most agencies, the storm may briefly reach typhoon strength before it interacts with land. Winds could reach between 100–120 kph as the system approaches Taiwan.
Even if not officially upgraded, impacts on land will resemble that of a minimal typhoon. Taiwan’s southwest coast is bracing for potential landfall or near-landfall conditions, including strong winds, torrential rain, and coastal flooding. Eastern Taiwan will likely see heavy rain first as moisture is funneled in ahead of the storm, before the southwesterly flow shifts the heaviest bands to the west side of the island.
Storm to Curve Toward China, Then Weaken
After passing near or across Taiwan, Bising is forecast to continue moving northwestward, but will soon encounter a ridge of high pressure over eastern China. This atmospheric barrier is expected to force the storm to bend westward, guiding it toward the vicinity of Shanghai. By then, however, the system will likely begin to weaken due to land interaction and increased wind shear.
China’s eastern seaboard—already vulnerable to flooding this season—is preparing for another bout of heavy rain and strong winds, though the core of Bising may weaken significantly before it makes final landfall.
No Threat from “Second Storm”
Social media buzz has incorrectly suggested that multiple tropical cyclones are targeting the Philippines simultaneously. In reality, the second weather system being mentioned is located far to the east, near the open waters south of Okinawa. This system is currently being swept northeastward by the mid-latitude jet stream and is not forecast to impact the Philippines.
Other convection observed south of Japan may also flare up, but these disturbances remain embedded in a pattern that favors recurvature away from land.
Rainfall Outlook and Monsoon Enhancement
Back in the Philippines, the southwest monsoon, or habagat, remains strongly enhanced by Bising. This broad “river of moisture” continues to stream into western Luzon, maintaining the potential for more rainfall even without a direct hit from the storm center.
Forecast models suggest that rainfall in Region 1 (Ilocos Region) will remain high through at least Thursday, with totals of 200–300 mm not out of the question. Region 2 (Cagayan Valley) is seeing lighter showers, generally between 10–30 mm per day, tapering off slightly midweek.
While Luzon bears the brunt of the rainfall, the central and southern Philippines—including Cebu, Tacloban, and Mindanao—are largely spared, with only isolated showers and minimal wind impacts.
Sea Conditions and Travel Impacts
Rough seas are expected near the storm’s center, especially southwest of Taiwan where wave heights could reach 3–6 meters. Along the northwestern coastlines of the Philippines, wave heights of up to 3 meters are possible, particularly in Ilocos Norte and La Union.
Ferry travel in these areas may be suspended, and fishing operations are discouraged due to dangerous marine conditions. Coastal flooding is also a risk during high tides, especially in areas with poor drainage or recent rainfall accumulation.
Regional Forecast Highlights
- Metro Manila: Highs around 31°C, scattered afternoon thunderstorms expected through Wednesday.
- Baguio: Cooler at 23°C due to heavy cloud cover and rainfall; threat of mudslides remains.
- Pangasinan and Zambales: Persistent rainfall with localized flooding possible.
- Cagayan Valley: Occasional showers, especially over the Sierra Madre foothills, but generally lighter than areas to the west.
- Cebu and Visayas: Highs around 32°C with partly cloudy skies and isolated rain.
- Southwestern Taiwan: Increasing winds and rain, with potential typhoon conditions late Monday into Tuesday.
Looking Ahead
Improvement in the weather pattern is expected gradually from Thursday into the weekend for much of Luzon, though residual moisture could still support scattered showers during the afternoons. As Bising continues to move away and weaken over eastern China, the enhanced monsoon will begin to lose strength, offering some relief from the recent stretch of wet and windy days.
Until then, residents in western Luzon are advised to stay alert for weather updates, monitor for potential landslide warnings in high-risk areas, and be cautious of flooded roads and poor visibility.
Western Pacific Weather will continue to monitor Bising (Danas) closely and provide detailed updates through our social media channels and weather briefings. Stay safe, and stay informed.
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