Bopha (Pablo)
Current storm status Category 3 typhoon (1-min mean)
Satellite image Forecast map
As of:	00:00 UTC December 4
Location:	7.9°N 125.9°E About 225 nmi (417 km; 259 mi) ENE of Zamboanga City, Philippines
Sustained winds:	90 (10-min mean) 110 (1-min mean) gusting to 130
Pressure:	940
Movement:	W at 15 knots (28 km/h; 17 mph)
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Typhoon Bopha (international designation: 1224, JTWC designation: 26W, PAGASA designation: Pablo) is currently a powerful late-season tropical cyclone which formed unusually close to the equator. After affecting Palau, Bopha made landfall over Mindanao late on December 3, an island devastated by Washi in December 2011, becoming the strongest tropical cyclone ever to hit Mindanao.^[1]

Meteorological history

On November 23, a large area of convection persisted 650 km (400 mi) south of Pohnpei, near the equator or at latitude of 0.6ºN. The system had a poorly-defined, elongated atmospheric circulation, and was located in an area of moderate wind shear and restricted outflow, due to a subtropical ridge to the north. As a result, the Joint Typhoon Warning Center (JTWC) assessed a low chance for tropical cyclogenesis.^[2] The center slowly consolidated, with a well-defined mid-level circulation.^[3] Late on November 25, the JTWC issued a tropical cyclone formation alert after it organized further, noting that the system had developed an anticyclone which was providing outflow.^[4] Around the same time, the Japan Meteorological Agency (JMA) classified the system as a tropical depression, about 410 km (255 mi) south-southwest of Pohnpei.^[5] At 2100 UTC on November 25, the JTWC also upgraded the system to Tropical Depression 26W.^[6]

Upon developing, the depression had deep convection located in rainbands around the increasingly consolidating center; however, the center initially was difficult to locate. With minimal wind shear and overall favorable conditions, the system was expected to gradually intensify as it moved generally westward, steered by the ridge to the north.^[7] On November 26, the movement became nearly stationary as the center organized further.^[8] Later that day, the JMA upgraded the depression to Tropical Storm Bopha,^[9] and early on November 27 the JTWC followed suit after a strong burst of thunderstorms over the center.^[10] Its westward motion increased on November 28,^[11] later becoming west-southwestward. The convection gradually became better organized and wrapped into the center, indicative of a strengthening storm.^[12] However, early on November 29 the appearance degraded, with the thunderstorms limited to the southern periphery due to reduced outflow to the south.^[13] The circulation became exposed,^[14] and the JTWC noted that Bopha was unable to intensify significantly due to its low latitude and correspondingly low Coriolis effect. Late on November 29, convection increased, aided by warm waters and low wind shear.^[15] At 0000 UTC on November 30, the JMA upgraded Bopha to a severe tropical storm.^[16] A few hours later, the JTWC upgraded the storm to a typhoon,^[17] and the JMA followed suit at 1800 UTC that day.^[18] At that time, Bopha was located about 980 km (610 mi) east-southeast of Palau.^[19]

As the system continued to intensify, organize bands of thunderstorms, began to develop rapidly around the system, mostly on the western half of the storm, which later merged with Bopha, which lead to the system's increase in size. Several hot towers also began to rise up near the low level circulation center, with on of the hot towers reaching 17 km (11 mi) into the atmosphere.^[20] At around the same time, on November 30, a ragged, eye-like feature appeared in microwave imagery, which later transitioned into a small 25 km (16 mi) wide and defined pinhole eye by December 1. The stadium effect was also observed in the thick convection surrounding the eyewall, involving thin strips clouds from the eyewall curve outward from the surface with height. At around the same time the system's eye structure improved, it began to explosively intensify, becoming a category 4 storm in 18 hours, while being less than five degrees from the equator.^[21] On December 1, the system, as a category 4 typhoon, maintained a well defined, small eye, which later dissipated, but reformed by December 2. As Bopha strengthened further into a super typhoon on December 2, the well-defined eye underwent a small eyewall replacement cycle by late December 2, and by 1000 UTC on December 2, the system developed double eyewalls, which were only seen in microwave imagery. Late on December 2, at 1230 UTC Bopha neared Palau, with a closest distance of 50 kilometers. At that time, the system's outflow improved, with convection near the eye thickened. Early on December 3, due to the eyewall replacement cycle, the system weakened slightly into a category 3 typhoon, however, a few hours later, as the eyewall replacement cycle ended, Bopha reintensified into a category 4 typhoon, while the eye becomes well-defined again. Late on December 3, as the system continue to strengthen, the system unexpectedly rapidly intensified into a category 5 super typhoon, and the pinhole eye became very-well defined.^[22]

Preparations and impact

Federated States of Micronesia and Palau

When Bopha was forming, the National Weather Service (NWS) in Guam issued a tropical storm watch for the FSM islands of Nukuoro and Lukunor.^[23] The watch was upgraded to a tropical storm warning on November 26, and the watch was expanded to include Losap and Chuuk Lagoon.^[24] As Bopha moved westward, the office also issued a tropical storm watch for Poluwat,^[25] and Satawal,^[26] both of which were upgraded to warnings, and a typhoon watch was issued for Woleai.^[27] On November 30, authorities and disaster managers on Palau island are on high alert with predictions that Typhoon Bopha will pass directly over Palau as a Category 3 tropical cyclone by December 2. Authorities on Palau has requested assistance from the US Construction and Civic Action Detail (CCAD) Team, to prepare for the incoming storm. The National Emergency Management Office in Palau issued a Public Announcement on November 29 requesting a public stock up, with emergency supplies such as food and water for three days, portable radios with spare batteries, flashlights, first aid kits. The citizens of Palau were also advised to start cleaning their houses, secure loose objects that may be lifted up by the strong winds, which can cause massive damage, board up windows, trim tree branches that could fall and damage homes, fill up vehicles with gas, secure boats and assist their communities in preparing.^[28]

As Typhoon Bopha passed to the south of the island, power outages occurred across the island chain.^[29] Communication network disruptions delayed updates on damage assessments after the storm passed. Initial damage assessments in Korror indicated slight damage, with uprooted trees and power disruption. Outside of Korror, coastal villages were effected by strong winds and rain, which flooded outlying areas.^[30] Heavy rains flooded areas of Peleliu, and houses in Babeldaob were destroyed.^[31]

Philippines

Initially, the National Disaster Risk Reduction and Management Council (NDRRMC) advised the citizens of Iligan and Cagayan de Oro to prepare for the impact of the storm, as they do not want a repeat of Severe Tropical Storm Washi, which hit when people were asleep and caused a large number of deaths.^[32]

December 2

Bopha was locally known as Pablo. On December 2, the NDRRMC put parts of the central and southeastern Philippines on high alert. Relief food and medicines have been pre-positioned while thousands of people along the country's eastern border were being prepared for evacuation to safer ground in preparation for the typhoon.^[33] Bopha was expected to strike Mindanao and Visayas, as well as areas in Southern Tagalog and Metro Manila. Possibility of landslides was adviced in Surigao, Davao, Compostela Valley, Misamis, Bukidnon, Lanao, Zamboanga, Leyte, Cebu, Bohol, Negros, Panay and Mindoro.^[34] A government-run radio station dzRB, in its regular Sunday press briefing aired Deputy Presidential Spokesperson Abigail Valte's call on all responsible government agencies, the media, non-government volunteer groups and volunteers to do their part in preparing for the typhoon. "Keep updated on the bulletins from PAGASA. Always cooperate with the local authorities as the National Government is all ready to provide all assistance to those that may be affected," Valte said.^[35] Also, disaster authorities in Bicol were alerted and getting ready with their disaster contingency plan as the typhoon was closing in.^[36]

December 3

On December 3, some 2,000 families living in the islands of Hinatuan, Surigao del Sur were evacuated. Since schools would be turned into evacuation centers, Candelario Viola, the mayor of Hunatuan, ordered the suspension of all classes in the town.^[37] Mar Roxas, the Interior and Local Government Secretary, said that NDRRMC’s disaster monitoring systems were set up in several regions across the Philippines. "In accordance with President PNoy’s (Benigno Aquino III) marching orders to ensure zero casualties from disasters, as much as possible, I have ordered our regional directors to make sure that the necessary precautions are undertaken to mitigate the effects of Tropical Storm Bopha," he said. "We have our existing protocols, and it is just a matter of implementing them and making other necessary preparations as appropriate." Roxas added.^[38] As preparations continued, Storm signal number 1 was declared over Siquijor, Bohol, Biliran, Camotes Island, Southern Leyte, Leyte, Eastern Samar, Western Samar, Surigao del Norte, Siargao Island, Dinagat Island, Agusan del Norte, Agusan del Sur, rest of Davao Oriental, Davaol del Norte including Samal Island, Compostela Valley, Bukidnon, Misamis Occidental, Misamis oriental, Camiguin, Lanao del Norte and Lanao del Sur. Also, signal number 2 was raised over Surigao del Sur and the northern part of Davao Oriental.^[39] The Philippine National Police (PNP), Philippine Coast Guard (PCG) and the Navy had placed their personnel on standby and their disaster response units in preparation for Bopha's impact. "We are ready to conduct rescue operations in flooded areas. Let us warn operators of small vessels, motor bancas, and fishing boats to avoid sailing in the southeastern and eastern section of the country where sea is rough," said PCG spokesman Commander Armand Balilo.^[40]

See also

• Severe Tropical Storm Washi
• Tropical Storm Vamei
• 2012 Pacific typhoon season
• Typhoon Kate (1970)
• List of Equatorial tropical cyclones

References

External links