Typhoon Vongfong (2020)

Typhoon Vongfong, known in the Philippines as Typhoon Ambo, was a strong tropical cyclone that impacted the Philippines in May 2020. Beginning as a tropical depression on May 10 east of Mindanao, Vongfong was the first storm of the 2020 Pacific typhoon season. It gradually organized as it took a slow northward course, strengthening into a tropical storm on May 12 and curving west thereafter. The next day, Vongfong entered a period of rapid intensification, becoming a typhoon and attaining 10-minute maximum sustained winds of . The storm made landfall at this intensity near San Policarpo, Eastern Samar, at 04:15  UTC on May 14. The system tracked across Visayas and Luzon, making a total of seven landfalls. Persistent land interaction weakened Vongfong, leading to its degeneration into a tropical depression over the Luzon Strait on May 17.

Preparations for the typhoon were complicated due to the ongoing COVID-19 pandemic. Shelters that opened had to be modified in order to accommodate health guidelines and social distancing. Throughout the Philippines, Vongfong caused around ₱1.57 billion (US$31.1 million) in damage, and killed five people.

Meteorological history

In early May of 2020, an area of atmospheric convection began to persist approximately southeast of Palau, situated within an environment generally conducive for the formation of a tropical cyclone. However, upper-level wind shear initially prevented much development. Satellite data suggested the presence of broad cyclonic rotation within the disturbance, which was designated ''Invest 95W'' by the JTWC. Computer forecast models predicted that the system would track slowly towards the west-northwest. The circulation associated with the storms persisted over subsequent days, and at 00:00  UTC on May 10, the Japan Meteorological Agency (JMA) determined that a tropical depression had developed east of Mindanao, tracking slowly west. Later that day, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) followed suit and upgraded the system to a tropical depression, giving it the name ''Ambo'' for Filipino interests; it was the first tropical cyclone within the Philippine Area of Responsibility in 2020 and the first of the 2020 Pacific typhoon season. On the same day, a Tropical Cyclone Formation Alert (TCFA) was issued by the JTWC on the system, noting early signs of rainband development. Though attenuated by the presence of dry air, warm sea surface temperatures, low wind shear, and upper-level outflow supported further development in the storm's early stages as the storm was steered by subtropical ridge. Weak steering currents caused the tropical depression to move slowly northward on May 12. At 12:00 UTC on May 12, the JMA upgraded the system to a tropical storm, assigning it the name ''Vongfong''.Vongfong's cloud tops were rapidly cooling and consolidating upon its upgrade to a tropical storm, indicative of a strengthening cyclone. The storm also began to develop anticyclonic outflow and curved rainbands. A well-defined eye soon emerged on microwave satellite imagery as the storm's structure became further organized, surrounded by hot towers with the storm tracking nearly due west in response to a subtropical ridge centered over the Northern Mariana Islands. At 06:00 UTC on May 13, the JMA upgraded Vongfong to severe tropical storm status, followed by an upgrade to typhoon status six hours later. The eye became increasingly pronounced and contracted to less than in diameter as the storm's evolution became suggestive of rapid intensification. The JTWC assessed 1-minute sustained winds of at 21:00 UTC on May 13 shortly before the onset of an eyewall replacement cycle; nine hours later, the JMA analyzed Vongfong to have attained 10-minute sustained winds of and a barometric pressure of 965 hPa (mbar; 28.50  inHg). Vongfong made landfall with this intensity over San Policarpo, Eastern Samar, at 04:15 UTC on May 14. The storm's structure degraded due to land interaction as it traversed Samar, causing Vongfong's eye to dissipate. Vongfong made six additional landfalls as it traversed the remainder of the Visayas into Luzon: Dalupiri Island; Capul Island; Ticao Island; Burias Island; San Andres, Quezon; and Real, Quezon. The prolonged interaction with land caused Vongfong to weaken, though the storm maintained a compact circulation amid otherwise favorable atmospheric conditions. On May 15, Vongfong weakened below typhoon status and began to track towards the northwest around the periphery of a subtropical ridge. It weakened further to a tropical storm by 18:00 UTC that day. The center moved off Luzon and became dislocated from atmospheric convection over the Luzon Strait the following day. At 09:00 UTC on May 16, the JTWC issued its final warning on the system. Nine hours later, the JMA downgraded Vongfong to tropical depression status. The PAGASA declared Vongfong to have dissipated on May 17 while over the Bashi Channel.

Preparations

Heavy rainfall warnings were triggered by the storm's approach for Caraga Region, Bukidnon and Davao del Norte provinces on May 11. The following day, the PAGASA urged residents to begin preparing for the storm, particularly in the Bicol and Eastern Visayas regions and parts of Luzon. Tropical Cyclone Wind Signal 1 was issued parts of Eastern Samar and Northern Samar by the agency on May 13; this was later extended to include parts of the Bicol region. Tropical Cyclone Wind Signal 3 was ultimately issued for parts of Bicol and Eastern Visayas on May 14 as Vongfong neared landfall.

Search and rescue teams in Davao City were advised by the municipal government to be placed on alert for possible landslides and flooding. The 18 Risk Reduction and Management Offices of Albay