Tropical Storm Gaemi (2012)
Severe Tropical Storm Gaemi, known in the Philippines as Tropical Storm Marce, was an erratic tropical cyclone that affected the Philippines and Vietnam in early October 2012. The twentieth named storm of the annual typhoon season, Gaemi originated as an area of convection over the central South China Sea on September 29. The system went northeastward and slowly gaining strength. On October 1, the depression strengthened into Tropical Storm Gaemi as it turned southeastward. Gaemi briefly attained severe tropical storm status on October 3, but weakened back to a tropical storm later that day. On the next day, Gaemi turned west-southwest and continued to slowly weakened. The storm made landfall in southern Vietnam on October 6 and weakened to a tropical depression shortly after landfall, before dissipating on the next day over Cambodia.
As Gaemi meandered over the West Philippine Sea, it enhanced the southwest monsoon and brought rainfall to western Luzon and caused flooding. Storm surge in the region damaged houses and flooded bridges. Gaemi then struck southern Vietnam as a minimal tropical storm, and brought strong winds and heavy rainfall. Landslides occurred in Phú Yên province and blocked roads and bridges. The South Central Coast suffered from extensive crop damage. In total, Gaemi killed six people and left one other missing. Damage related to the storm accumulated US$4.12 million.
Meteorological history
On September 29, an area of convection presisted over the central South China Sea. The Japan Meteorological Agency designated it as a tropical depression at 00:00 UTC. The center was well-organized with convection increased over the center. The system slowly drifted northeastward and continued to consolidate, which prompted the Joint Typhoon Warning Center issued a Tropical Cyclone Formation Alert on the next day. At 12:00 UTC October 1, the JMA upgraded the system to a tropical storm, and assigned the name Gaemi. The JTWC initiated advisory on Tropical Depression 21W three hours later, as deep convection formed over the southeast of the center. It benefited from warm sea surface temperature of and good equatorward outflow. Steering current remained weak because a mid-latitude trough weakened a subtropical ridge over the southeastern China, and Gaemi remained almost stationary. Despite lacking deep convection over the northern part of the center, a scatterometer passed by and revealed that the system attained gale-force winds. As such, the JTWC upgraded it to a tropical storm at 21:00 UTC. Gaemi gradually strengthened under low wind shear and good equatorward outflow. The storm started to move southeastward as steered by a near-equatorial ridge to its south.On October 2, Gaemi entered the Philippine Area of Responsibility, the Philippine Atmospheric, Geophysical and Astronomical Services Administration began tracking the system and gave the local name Marce. Poleward outflow improved later that day, and Gaemi developed a central dense overcast. At 06:00 UTC October 3, Gaemi attained severe tropical storm status and attained peak intensity with winds of 95 km/h and a barometric pressure of concurrently. However, the peak of Gaemi was short-lived as wind shear increased. Gaemi weakened to a tropical storm 12 hours later. Deep convection was sheared to the west, and the center became fully exposed. The storm turned sharply to the west on October 4, under the influence of a subtropical ridge to its north. Wind shear remained strong on October 5. The center was slightly elongated and remained fully exposed with deep convection being sheared to the west while moving west-southwest. Later that day, Gaemi left the PAR, and the PAGASA ceased monitoring the system. On October 6, Gaemi re-strengthened slightly as large area of deep convection concealed part of the center. At 18:00 ICT, Gaemi made landfall in Phú Yên province, near Tuy Hòa, as a minimal tropical storm. It weakened to a tropical depression just an hour after landfall. The JTWC issued its final advisory on the system later that day, though the JMA continued to track it. Gaemi dissipated on the next day over western Cambodia.