FLASH UPDATE #1 – Enhanced Southwest Monsoon and Tropical Cyclone CO-MAY
Country under monitoring: Philippines
OVERVIEW: The low pressure area west of Luzon has rapidly intensified to a typhoon with international name “CO-MAY.” According to PAGASA , as of 1900H UTC+7, Tropical Cyclone CO-MAY maintains its strength and is nearing landfall over Western Pangasinan. The centre of the eye of the tropical cyclone was estimated based on all available data over the coastal waters of Burgos, Pangasinan.
STRENGTH, EXTENT, & MOVEMENT: According to PAGASA’s Tropical Cyclone Bulletin No. 10, 24 July at 1900H UTC+7:
- Maximum sustained winds at 120 km/h with gustiness up to 165 km/h, minimum central pressure at 975 hPa, moving eastward slowly. Strong winds extend outwards up to 240 km from the centre
FORECAST & ANALYSIS: According to PAGASA Tropical Cyclone Bulletin as of 1900H UTC+7:
TRACK: CO-MAY is forecast to gradually accelerate, initially eastward then northeastward tonight. On the track forecast, the typhoon will make landfall or pass very close to western Pangasinan in the next 3 hours. The typhoon may also make landfall in La Union or Ilocos Sur this late evening or tomorrow (25 July) early morning. It will then cross the mountainous terrain of Northern Luzon and emerge over the Babuyan Channel tomorrow morning or noon. Afterwards, CO-MAY will move northeastward and pass close or over Babuyan Islands between tomorrow noon and afternoon. It may also be passing near Batanes between tomorrow afternoon or evening.
INTENSITY: CO-MAY may still briefly intensify prior to landfall due to its compact circulation and favorable atmospheric and oceanic environment. While a landfall scenario as a typhoon remains the more likely scenario, a slight weakening prior to landfall due to increasing interaction with the terrain of northwestern Luzon is not ruled out. Nevertheless, the passage of CO-MAY will trigger a weakening trend, which is expected to continue for the rest of the forecast period
TROPICAL CYCLONE WIND SIGNALS IN EFFECT:
- TCWS No. 4 Warning lead time 12 hours, range of wind speeds: 118 to 184 km/h (Beaufort 12) is raised over the following areas: The southwestern portion of Ilocos Sur, the northwestern portion of La Union, and the extreme northwestern portion of Pangasinan.
- TCWS No. 3 Warning lead time 18 hours, range of wind speeds: 89 to 117 km/h (Beaufort 10 to 11) is raised over the following areas: The southern portion of Ilocos Norte the rest of Ilocos Sur, the rest of La Union, the northern and western portions of Pangasinan, Abra, the western portion of Mountain Province, and the western portion of Benguet.
- TCWS No. 2 Warning lead time 24 hours, range of wind speeds: 62 to 88 km/h (Beaufort 8 to 9) is raised over the following areas: The rest of Ilocos Norte, the rest of Pangasinan, Apayao, Kalinga, the rest of Mountain Province, Ifugao, the rest of Benguet, Babuyan Islands, the northern and western portions of mainland Cagayan, the western portion of Nueva Vizcaya, and the northern portion of Zambales
- TCWS No. 1 Warning lead time 36 hours, range of wind speeds: 39 to 61 km/h (Beaufort 6 to 7) is raised over the following areas: Batanes, the rest of Cagayan, the western and central portions of Isabela, Quirino, the rest of Nueva Vizcaya, the rest of Zambales, the northern portion of Bataan, Tarlac, the northern portion of Pampanga, and the western and central portions of Nueva Ecija.
HAZARDS:
- Severe Winds – The wind signals warn the public of the general wind threat over an area due to the tropical cyclone. Local winds may be slightly stronger/enhanced in coastal and upland/mountainous areas exposed to winds. Winds are less strong in areas sheltered from the prevailing wind direction.
- Significant to severe impacts from typhoon-force winds are possible within any of the localities where Wind Signal No. 4 is hoisted.
- Moderate to significant impacts from storm-force winds are possible within any of the localities where Wind Signal No. 3 is hoisted.
- Minor to moderate impacts from gale-force winds are possible within any of the localities where Wind Signal No. 2 is hoisted.
- Minimal to minor impacts from strong winds are possible within any of the areas under Wind Signal No. 1.
- The Southwest Monsoon will bring strong to gale-force gusts over the following areas (especially in coastal and upland areas exposed to winds):
- Today: Central Luzon (areas not under Wind Signal), Metro Manila, CALABARZON, Bicol Region, MIMAROPA, Visayas, Zamboanga del Norte, Misamis Occidental, Lanao del Norte, Camiguin, Dinagat Islands, and Davao Oriental.
- Tomorrow (25 July): Central Luzon (areas not under Wind Signal), Metro Manila, CALABARZON, Bicol Region, MIMAROPA, Visayas, Zamboanga del Norte, Misamis Occidental, Lanao del Norte, and Camiguin.
- Saturday (26 July): Batanes, Babuyan Islands, Ilocos Region, Isabela, Quirino, Nueva Vizcaya, Central Luzon, Metro Manila, Bicol Region, MIMAROPA, Visayas, Zamboanga del Norte, Misamis Occidental, Lanao del Norte, and Camiguin.
- Heavy Rainfall – Heavy rainfall outlook due to Tropical Cyclone CO-MAY & Southwest Monsoon is issued for the following areas:
- Today to Tomorrow afternoon:
- >200 mm: Ilocos Sur, La Union, Pangasinan, Zambales, Benguet, Bataan and Occidental Mindoro
- 100-200 mm: Ilocos Norte, Abra, Mountain Province, Ifugao, Pampanga, Cavite, Batangas, Tarlac, and Laguna
- 50-100 mm: Cagayan, Kalinga, Apayao, Isabela, Nueva Vizcaya, Nueva Ecija, Metro Manila, Bulacan, Rizal, Quezon, Aurora, Quirino, Oriental Mindoro, Palawan, Marinduque, Romblon, Camarines Norte, Camarines Sur, and Albay.
- According to PAGASA, the amount of rainfall may cause the following impacts:
- >200mm rainfall: Widespread incidents of severe flooding and landslides expected.
- 100-200mm rainfall: Numerous flooding events are likely especially in moderate to highly susceptible areas. Landslide likely in moderate to highly susceptible areas.
- 50-100mm rainfall: Localised flooding is possible mainly in areas that are urbanised, low-lying, or near rivers. Landslide possible in highly susceptible areas.
- Coastal Inundation – There is a moderate to high risk of life-threatening storm surge with peak heights reaching 1.0 to 3.0 m within 24 hours over the low-lying or exposed coastal localities of Batanes, northern mainland Cagayan, Babuyan Islands, Ilocos Norte, Ilocos Sur, La Union, Pangasinan, and Zambales.
ANTICIPATED RISK:
- Forecast rainfall may be higher in mountainous and elevated areas. Moreover, impacts in some areas may be worsened by significant antecedent rainfall.
- Areas along the forecast track which include major floodplains, mountainous terrains, and highly urbanised areas are highly susceptible to flooding and landslides.
- Potentially exposed communities may have already been affected by recent and ongoing flooding, further exacerbating current conditions and increasing vulnerabilities.
ACTIVE DISASTERS:
- According to NDRRMC Situation Report No. 15, as of 1700H UTC+7 today, the combined effects of Tropical Cyclone WIPHA and the enhanced Southwest Monsoon have affected a total of 3.34M affected population in 17 regions, 66 provinces, and 501 cities/municipalities. Casualties include 19 deaths, eight injuries, and 11 missing individuals. The widespread flooding and related incidents displaced about 273K displaced population. A total of 1.15K ECs are currently serving displaced communities. A total of 969 areas in Regions I, II, III, IVA, IVB, V, VI, VII, IX, XII, CARAGA, NIR, and NCR have been flooded while a total of 59 other related incidents have been reported.
PREPAREDNESS AND RESPONSE:
- NDRRMCOC maintains its alert status at RED. PAGASA continues close monitoring, releases Tropical Cyclone Bulletins, advisories, and conducts regular press briefings on the active weather disturbances. DENR-MGB has released list of cities, municipalities, and barangays susceptible to rain-induced landslides along the areas with heavy rainfall outlook.
- The NDRRMC-OCD has issued a strong warning over the increased risk of flooding and landslides in Northern and Central Luzon and parts of Metro Manila, following weeks of continuous rainfall that have saturated soil in high-risk areas. OCD has been optimising the use of media channels to inform and provide warnings to the public.
- NDRRMC-OCD continues to work closely with local government units (LGUs) in enforcing pre-emptive evacuations and ensuring community safety.
- The NDRRMC follows an intensified coordination in line with the whole-of-government and whole-of-society approach, ensuring all sectors work in unison to address disasters and save lives. According to OCD, relief efforts remain sustained and resources have been prepositioned nationwide, ready for deployment when needed
The AHA Centre will continue to monitor for further developments and issue necessary updates.
DATA SOURCES
ASEAN Disaster Monitoring & Response System (DMRS), ASEAN Disaster Information Network (ADINet); Pacific Disaster Center (PDC Global); ASEAN Specialised Meteorological Centre (ASMC);
Lao PDR: NDMO Lao PDR, DMH;
Philippines: NDRRMC-OCD, PAGASA;
Thailand: DDPM, TMD;
Viet Nam: VDDMA, NHCMF;
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