Tropical Storm Conson

Severe Tropical Storm Conson (transliterated from Vietnamese Côn Sơn), known in the Philippines as Typhoon Jolina, was a strong tropical cyclone that impacted the central Philippines and Vietnam during early September 2021. The thirteenth named storm of the annual typhoon season, Conson originated from a low-pressure area approximately 500 km (310 mi) west of Guam. It strengthened into a tropical depression on September 5, and as it formed within the Philippine Area of Responsibility (PAR), the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) named the system Jolina. Over the next day, it intensified into a tropical storm and was named Conson by the Japan Meteorological Agency (JMA). As the storm neared Samar Island, it intensified into a severe tropical storm, and later into a typhoon according to the PAGASA prior to its first landfall in Eastern Samar. The storm retained its strength as it crossed the Visayas, and later, Calabarzon before weakening over Manila Bay prior to its final landfall in Bataan. It subsequently emerged into the South China Sea, where it struggled to further reintensify. Conson was then downgraded to a tropical depression just offshore of Vietnam before moving ashore near Da Nang, rapidly weakening before dissipating on September 13.

The National Disaster Risk Reduction and Management Council (NDRRMC) of the Philippines reported 23 fatalities, 32 injuries and two missing individuals. Agricultural and infrastructural damages in the country were estimated at ₱5.17 billion (US$88.3 million).

At 06:00 UTC on September 5, the United States Joint Typhoon Warning Center (JTWC) started monitoring a tropical disturbance in the Philippine Sea, located about 446 nmi (513 mi; 826 km) east-southeast of Legazpi, Albay. Multispectral satellite imagery at the time showed a low-level circulation center (LLCC) with cloud lines wrapping around the feature. The system was also situated in a favorable environment for further development, characterized by poleward outflow, favorable wind shear, and sea surface temperatures of around 30 °C (86 °F). Over the next several hours, it gradually organized while remaining nearly stationary. At 18:00 UTC that day, the JMA upgraded the system to a tropical depression, while the PAGASA simultaneously named it Jolina after it entered the PAR, making it the tenth tropical cyclone of the season in the area. Later that day, at 23:30 UTC, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) as circulation became more pronounced, accompanied by an organizing convective band to the south-southeast of the center.

The following day, the agency reported that the system had further consolidated, with persistent thunderstorms developing over an obscured LLCC, and upgraded it to a tropical depression. Moving northwestward along the southwestern periphery of a subtropical ridge to the northeast, the system's organization steadily improved and an eye feature began to form. At 06:00 UTC, the depression strengthened into a tropical storm according to both the JMA and PAGASA, with the former assigning the name Conson. The JTWC also followed suit three hours later. At around the same time, 09:00 UTC (17:00 PHT), PAGASA further upgraded the system to a severe tropical storm as it neared Samar Island. Convection expanded eastward from the southeast quadrant, prompting the JMA to raise its classification two hours later. Conson subsequently intensified into a typhoon and made landfall over Hernani, Eastern Samar, at 14:00 UTC (22:00 PHT). It then traversed the Visayas, making additional landfalls in Daram, Samar, Santo Niño, Samar, Almagro, Samar, and Tagapul-an, Samar in Samar during a period of nearly six hours, from 18:00 to 23:50 UTC (02:00 to 07:50 PHT on September 7). While crossing Samar, the system continued to consolidate and briefly developed a small microwave eye.

Early on September 7, Conson made another landfall in Dimasalang, Masbate at 02:00 UTC (10:00 PHT). Interaction with land slightly weakened the system, and its LLCC became ragged. While traversing the Sibuyan Sea, however, Conson briefly produced a well-defined radar eye while maintaining its strength. It went on to make landfall in Torrijos, Marinduque at 16:15 UTC (00:15 PHT on the next day), followed by another in San Juan, Batangas at 01:00 UTC (09:00 PHT) on September 8. Despite crossing South Luzon, Conson maintained its strength while moving across Calabarzon. Over Manila Bay, its LLCC became increasingly disorganized, and PAGASA downgraded the system to a tropical storm. Conson made its final Philippine landfall in Mariveles, Bataan, at 09:00 UTC (17:00 PHT). At 12:00 UTC, it reintensified into a severe tropical storm before emerging into the South China Sea about three hours later.

Conson tracked westward across the South China Sea but struggled to consolidate. It retained tropical storm strength in a marginally favorable environment characterized by warm sea surface temperatures and moderate vertical wind shear persisted over the South China Sea until September 9. On September 10, increasing shear exposed its LLCC, weakening the system as it moved westward. Conson briefly reorganized on September 11, regaining a defined LLCC, but the improvement was short-lived as wind shear again disrupted its structure. At 12:00 UTC that day, the JMA downgraded it to a tropical storm, while the JTWC successively downgraded it to a tropical depression at 18:00 UTC and again at 02:00 UTC on September 12. The weakened system stalled near Quảng Ngãi Province in the South Central Coast of Vietnam under a weak steering pattern between three ridges. At 21:00 UTC, the JTWC issued its final advisory, noting that Conson had already made landfall near Da Nang and was rapidly weakening inland. The JMA continued to monitor the storm until it dissipated entirely at 18:00 UTC on September 13.

Upon the system's designation as a tropical depression, the PAGASA raised Tropical Cyclone Wind Signals for Eastern Visayas and the extreme tip of Mindanao as well as the Bicol Region and some areas of Calabarzon and Mimaropa. As the system developed into a typhoon, portions of Samar and Eastern Samar were placed under Signal #3.

The Philippine Coast Guard (PCG) suspended sea trips in the northern tip of Mindanao as early as September 6. The PCG also suspended trips in Eastern Samar, Capiz, Negros Occidental, and the Bicol Region on September 7. 2,500 passengers were stranded in sea ports around Luzon and Visayas by evening. Flights from Manila to Tacloban and Legazpi Airport (and vice versa) were cancelled on September 7 due to inclement weather. On September 8, flights from Manila to Davao, Puerto Princesa, Singapore, Abu Dhabi and Taipei (and vice versa) were also cancelled, along with flights from Japan and Guam to Manila (and vice-versa).