Typhoon Roke (2011)
Encyclopedia
Typhoon Roke was a persistent and powerful tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...

 that affected Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, where some areas were damaged by another typhoon just a few weeks ago. It is the 15th named storm, the 10th severe tropical storm, the 6th typhoon of the 2011 Pacific typhoon season
2011 Pacific typhoon season
The 2011 Pacific typhoon season was the time of the year in which tropical cyclones form in the Western Pacific Ocean. The season ran throughout 2011 with most tropical cyclones forming between May and November. The scope of this article is limited to the Pacific Ocean to the north of the equator...

 and overall, the 27th tropical cyclone to be monitored by the Japan Meteorological Agency
Japan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...

 during the year.

Meteorological history

Early on September 8, a cluster of thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...

s came together as a low pressure area with improving outflow and a developing low-level circulation center (LLCC). Later that day, the Japan Meteorological Agency
Japan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...

 (JMA) upgraded the low pressure area to a tropical depression north-northeast of the Northern Mariana Islands
Northern Mariana Islands
The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands , is a commonwealth in political union with the United States, occupying a strategic region of the western Pacific Ocean. It consists of 15 islands about three-quarters of the way from Hawaii to the Philippines...

. Over the next two days, the system gradually drifted west and intensified slightly, prompting the Joint Typhoon Warning Center
Joint Typhoon Warning Center
The Joint Typhoon Warning Center is a joint United States Navy – United States Air Force task force located at the Naval Maritime Forecast Center in Pearl Harbor, Hawaii...

 (JTWC) to issue a Tropical Cyclone Formation Alert (TCFA) on it. Convection gradually consolidated the LLCC and the JTWC initiated advisories on the system on September 11, designating it with 18W. The next day, the depression drifted into the Philippine Area of Responsibility (PAR) and the Philippine Atmospheric, Geophysical and Astronomical Services Administration
Philippine Atmospheric, Geophysical and Astronomical Services Administration
The Philippine Atmospheric, Geophysical and Astronomical Services Administration is a Philippine national institution dedicated to provide flood and typhoon warnings, public weather forecasts and advisories, meteorological, astronomical, climatological, and other specialized information and...

 (PAGASA) initiated advisories on the depression, naming it Onyok. However, just as similar to Kulap, Onyok also exited the PAR in 6 hours from entering the region. In an advisory, the JTWC reported that there were at-least two more vortices
Vortex
A vortex is a spinning, often turbulent,flow of fluid. Any spiral motion with closed streamlines is vortex flow. The motion of the fluid swirling rapidly around a center is called a vortex...

 associated with the system, that caused an abrupt, erratic movement. However, being located in an area of warm sea surface temperatures and low vertical wind shear, the depression continued to strengthen and on September 13, the JMA upgraded the depression to a tropical storm and named it Roke.

On September 14, a Tropical upper tropospheric trough
Tropical Upper Tropospheric Trough
A tropical upper tropospheric trough , also known as the mid-oceanic trough, is a trough situated in upper-level tropics. Its formation is usually caused by the intrusion of energy and wind from the mid-latitudes into the tropics. It can also develop from the inverted trough adjacent to an upper...

 (TUTT) cell located approximately 05 degrees to the west of the system caused strong subsidence
Subsidence (atmosphere)
Subsidence in the Earth's atmosphere is most commonly caused by low temperatures: as air cools, it becomes denser and moves towards the ground, just as warm air becomes less dense and moves upwards...

 prompting the JTWC to downgrade Roke to a tropical depression. However, because of favorable atmospheric conditions, Roke strengthened again, and the JTWC re-upgraded Roke to a tropical storm. On September 16, the previously exposed LLCC was being re-consolidated with convection and Roke continued to strengthen again. Despite the upper low over the LLCC, Roke remained a warm-core tropical cyclone and the JTWC predicted that there were chances of Roke become a hybrid or a subtropical storm. On continuing its west-northwestward movement, Roke eventually slowed down to under 2 knots (1.1 m/s) with a tongue of cloud-free air entering the LLCC from the west side. Due to a mid-level warm anomaly, the subtropical transition was taking place at an unusually slow rate. Later, that day, Roke turned to the southwest and slowed down with convection consolidating and deepening near the LLCC. What began as a monsoonal depression with an elongated and weak LLCC was now more stronger and organized. Also, the TUTT cell above the system started weakening and and data from an ASCAT scatterometer pass revealed that the storm started to strengthen and the JTWC no longer expected a subtropical transition.

On September 17, the JTWC reported that Roke developed a small, deep convective eye with an unusually large convective band surrounding the southern periphery of the storm. At that time, Roke was approximately 170 nautical miles (314.8 km) east of Kadena Air Base
Kadena Air Base
, is a United States Air Force base in the towns of Kadena and Chatan and the city of Okinawa, in Okinawa Prefecture, Japan. Kadena Air Base is the hub of U.S. airpower in the Pacific, and home to the USAF's 18th Wing and a variety of associate units.-Units:The 18th Wing is the host unit at Kadena...

, Japan with winds of over 60 knots (32.7 m/s). As a result, the JMA upgraded Roke to a severe tropical storm. However, Roke soon started become elongated around the northeast quadrant as a response to the strong westerlies
Westerlies
The Westerlies, anti-trades, or Prevailing Westerlies, are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude, blowing from the high pressure area in the horse latitudes towards the poles. These prevailing winds blow from the west to the east, and steer extratropical...

 ahead of a mid-latitude trough. But this was not for too long. Roke quickly became organized again and developed an excellent equatoward outflow and continued to strengthen. Then, being located in an area of low vertical wind shear and abnormally high sea surface temperatures, Roke underwent rapid deepening
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...

 and became a Category 1 typhoon on the SSHS with a maximum sustained windspeed of 70 knots (38.1 m/s) (1-min sustained). The JTWC later reported that Roke underwent Explosive intensification, a more extreme case of rapid deepening that involves a tropical cyclone deepening at a rate of at least 2.5 mbar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...

 per hour for a minimum of 12 hours. Also, they added that Roke developed a 10 nautical miles (18.5 km) eye and a good poleward outflow
Outflow
Outflow may refer to:*Capital outflow - an economic term describing capital flowing out of a particular economy.*Bipolar outflow in astronomy represents two continuous flows of gas from the poles of a star....

 channel. On September 21, Typhoon Roke made landfall over Hamamatsu, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 at about 5:00 UTC (14:00 JST
Japan Standard Time
Japan Standard Time or JST is the standard timezone of Japan, and is 9 hours ahead of UTC. For example, when it is midnight in UTC, it is 09:00 in Japan Standard Time. There is no daylight saving time, though its introduction has been debated several times. Japan Standard Time is the same as...

).

Soon Roke started weakening as cloud tops started getting warmed up and eye diameter started to decrease. However, the system still maintained a near radial outflow and the convective structure continued to remain organized that kept Roke from dissipating rapidly. Although Roke entered a de-intensification phase, it still had plenty of strength that posed a great threat to regions of Japan. Being located approximately 330 nautical miles (611.2 km) southwest of Yokosuka, Kanagawa
Yokosuka, Kanagawa
is a city located in Kanagawa, Japan. As of 2010, the city had an estimated population of 419,067 and a population density of 4,160 people per km². It covered an area of 100.62 km²...

, the typhoon accelerated north-northwestward at approximately 16 knots (8.7 m/s) with winds of over 100 knots (54.4 m/s) (1-min sustained) being a Category 3 typhoon on the SSHS. Being embedded in the baroclinic zone, Roke started its extratropical transition. Also, land interaction severely weakened the storm to a minimal Category 1 typhoon with winds of under 70 knots (38.1 m/s) (1-min sustained). Only six hours later, the storm further weakened and accelerated northeastward at approximately 31 knots (16.9 m/s) with rapidly dissipating deep convection completely sheared to the northeast of the LLCC. As a result, the JTWC ceased advisories on the storm, as it became fully extratropical.

Taiwan

On September 16, the Central Weather Bureau
Central Weather Bureau
The Central Weather Bureau is the government meteorological research and forecasting institution of the Republic of China . In addition to meteorology, the Central Weather Bureau also makes astronomical observations, reports on sea conditions, and conducts research into seismology and provides...

, the government meteorological research and forecasting institution of the Republic of China
Republic of China
The Republic of China , commonly known as Taiwan , is a unitary sovereign state located in East Asia. Originally based in mainland China, the Republic of China currently governs the island of Taiwan , which forms over 99% of its current territory, as well as Penghu, Kinmen, Matsu and other minor...

 (Taiwan) reported that the outer bands of the storm might bring heavy rains to the northern part of the country over the next few days after slowly brushing the Japanese islands of Okinawa.

Japan

On September 16, the Japanese refiner company Nansei Sekiyu KK announced that they suspended marine operations for the rest of the week at its Nishihara refinery in Okinawa Prefecture
Okinawa Prefecture
is one of Japan's southern prefectures. It consists of hundreds of the Ryukyu Islands in a chain over long, which extends southwest from Kyūshū to Taiwan. Okinawa's capital, Naha, is located in the southern part of Okinawa Island...

 that produces some 100000 oilbbl/d as the storm neared land. Also, a football match was preponed by a day because of the storm's proximity to the island. The game was played during strong winds caused by Roke. On September 18, The national weather agency of Japan warned the residents of wide areas across the Japanese archipelago of heavy rainfall, landslides and flash flooding that the strengthening storm can trigger in Japan, after in changed course from heading towards the Okinawa Islands to mainland Japan. Also, concerns grew as the storm was heading towards the same area which was devastated by Talas, an unusually large but weak tropical cyclone that hit the region just a few weeks ago. Parts of the Kii Peninsula
Kii Peninsula
The is the largest peninsula on the island of Honshū in Japan. The area south of the “Central Tectonic Line” is called Nankii , and includes the most poleward living coral reefs in the world due to the presence of the warm Kuroshio Current, though these are threatened by global warming and human...

 which were still in ruins were in a great danger as water levels of the mud dam rose to 70 centimeters, just below its maximum capacity. It was feared that as the storm brushes the southern coast, it could worsen the conditions caused by Typhoon Talas. Hundreds of thousands of people in Japan were asked to evacuate their homes and move to safer places as Typhoon Roke neared southwestern Japan, on its way to hit the main island of Honshu
Honshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...

 with winds of over 100 knots (54.4 m/s). It was reported that a further 23,000 people in western Japan were advised to seek shelter from flood and landslide prone areas. Over a million people, more than double the numbers for typhoon Talas, living in Nagoya were also forced to evacuate. The typhoon was expected to batter the island nation for three continuous days, as it moved through the tsunami ravaged Fukushima Prefecture
Fukushima Prefecture
is a prefecture of Japan located in the Tōhoku region on the island of Honshu. The capital is the city of Fukushima.-History:Until the Meiji Restoration, the area of Fukushima prefecture was known as Mutsu Province....

. Rainwater may leak into the basements of the crippled Fukushima Daiichi Nuclear Power Plant's reactors. City officials in Nagoya upgraded the evacuation advisory to the strongest level available and doubled the number of people who are subjected to the notice as local rivers brimmed with heavy rain.

Japan

Impact
Casualties Damage (USD)
Deaths Missing
13 3 ?
Source =


On approaching Japan, the typhoon instantly claimed four lives in central and western Japan, leaving two more missing in Gifu Prefecture
Gifu Prefecture
is a prefecture located in the Chūbu region of central Japan. Its capital is the city of Gifu.Located in the center of Japan, it has long played an important part as the crossroads of Japan, connecting the east to the west through such routes as the Nakasendō...

 following widespread flooding triggered by the heavy rains. A large number of expressways were closed and up-to 200 flights were cancelled after floodwater reached knee-level. Toyota Motor Corp, a multinational
Multinational corporation
A multi national corporation or enterprise , is a corporation or an enterprise that manages production or delivers services in more than one country. It can also be referred to as an international corporation...

 automaker
Automaker
The automotive industry designs, develops, manufactures, markets, and sells motor vehicles, and is one of the world's most important economic sectors by revenue....

 headquartered in Toyota City
Toyota, Aichi
is a city located in the Mikawa region of Aichi Prefecture, Japan, east of Nagoya.Toyota's main plant, the Tsutsumi plant, is located here. The longstanding ties between the Toyota Motor Corporation and the town of Toyota-shi, formerly known as Koromo, gave the town its current...

, Aichi
Aichi Prefecture
is a prefecture of Japan located in the Chūbu region. The region of Aichi is also known as the Tōkai region. The capital is Nagoya. It is the focus of the Chūkyō Metropolitan Area.- History :...

, Japan, shut down 11 factories in central Japan eliminating evening shifts due to the typhoon. The Chief Cabinet Secretary
Chief Cabinet Secretary
__notoc__The of Japan is a Minister of State who is responsible for directing the Cabinet Secretariat. The main function of Chief Cabinet Secretary is to coordinate the policies of ministries and agencies in the executive branch...

 Osamu Fujimura
Osamu Fujimura
is a Japanese politician of the Democratic Party of Japan, a member of the House of Representatives in the Diet . A native of Osaka, Osaka and graduate of Hiroshima University, he was elected to the House of Representatives for the first time in 1993 as a member of the Japan New Party. He lost in...

 said, "We need to exercise the maximum caution against heavy rain, strong winds and high waves in wide areas from western to northern Japan, according to the Meteorological agency". Soon, the strong winds and heavy rains cut power to more than 575,500 households in Tokyo Electric Power Company's service area. Also, commuter trains were halted and thousands of passengers were stranded though they tried to go home early before the storm hit Tokyo
Tokyo
, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...

. Later on September 21, local police and media reported that thirteen people were dead after being swept away by overflowing rivers. Unlike Talas, Roke moved significantly fast both inland and over the ocean. However, it was also unusually stronger. Also, the Nissan Motor Company's spokesman Chris Keeffe said "workers at its Yokohama headquarters and nearby technical facilities were being told to go home early for safety reasons, and two plants were not operating."
Typhoon Roke caused no immediate problems other than broken security cameras at the Fukushima Dai-ichi nuclear power plant, which had been in its path overnight. The plant had been sent into meltdown by the March 11 earthquake and tsunami, and efforts are still under way to bring the reactors under control.

Other areas

The extratropical remnants of Typhoon Roke hit parts of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Heavy rain fell in the Alaska Panhandle
Alaska Panhandle
Southeast Alaska, sometimes referred to as the Alaska Panhandle, is the southeastern portion of the U.S. state of Alaska, which lies west of the northern half of the Canadian province of British Columbia. The majority of Southeast Alaska's area is part of the Tongass National Forest, the United...

 and British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

.

See also

  • 2011 Pacific typhoon season
    2011 Pacific typhoon season
    The 2011 Pacific typhoon season was the time of the year in which tropical cyclones form in the Western Pacific Ocean. The season ran throughout 2011 with most tropical cyclones forming between May and November. The scope of this article is limited to the Pacific Ocean to the north of the equator...

  • Tropical Storm Talas (2011)
    Tropical Storm Talas (2011)
    Severe Tropical Storm TalasAccording to advisories from the JMA, Talas at peak strength was a typhoon . However, the JMA downgraded Talas to a severe tropical storm in RSMC Best Track Data...


External links

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