Typhoon Sepat (2007)

Infobox Hurricane
Name = Typhoon Sepat
Basin=WPac
Image location = Sepat 16 aug 2007 0225Z.jpg
JMAtype=typhoon
Type=typhoon
Formed = August 11, 2007
Dissipated = August 20, 2007

Luzon
10-min winds = 110
Pressure = 910
1-min winds = 140
Fatalities = At least 43
Damages = 692.5
Damagespre = At least
Year = 2007
Areas = Philippines, Taiwan, China
Hurricane season = 2007 Pacific typhoon season

Typhoon Sepat (international designation: "0708", JTWC designation: "09W", designated Typhoon Egay by PAGASA and sometimes called Super Typhoon Sepat) was the eighth tropical storm of the 2007 Pacific typhoon season that affected the Philippines and made landfall in Taiwan and Fujian.

Meteorological history

On August 11, a low-level circulation center formed in conjunction with a persistent area of convection about 1280 km (800 mi) southeast of Naha, Okinawa. Northerly upper-level winds initially provided beneficial divergence, though also resulted in detrimental wind shear and lack of inflow.cite web|author=Alpha Forecast Team|year=2007|title=August 11 Significant Tropical Weather Advisory|publisher=Joint Typhoon Warning Center|accessdate=2007-08-15|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081106-ABPW.PGTW] Upper-level conditions gradually became more favorable for development as the disturbance tracked along the eastern periphery of an upper-level anticyclone. With convective rain bands wrapping into the circulation, the Joint Typhoon Warning Center (JTWC) issued a tropical cyclone formation alert on the system late on August 11.cite web|author=Bravo Forecast Team|year=2007|title=August 11 Significant Tropical Weather Advisory (2)|publisher=Joint Typhoon Warning Center|accessdate=2007-08-15|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081121-ABPW.PGTW] Remaining nearly stationary between ridges to its northeast and southwest, the system developed further, and early on August 12 the JTWC classified it as Tropical Depression 09W.cite web|author=Joint Typhoon Warning Center|year=2007|title=Tropical Depression 09W Discussion NR 001|accessdate=2007-08-15|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081209-WTPN.PGTW] Shortly thereafter, the Japan Meteorological Agency (JMA) classified it as a tropical depression while located about 1245 km (775 mi) southeast of Okinawa.cite web|author=Japan Meteorological Agency|year=2007|title=Tropical Cyclone Advisory|accessdate=2007-08-15|url=http://www.webcitation.org/5R27gMhi1]

Twelve hours later, the JTWC upgraded the tropical depression to a tropical storm [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081215-WTPN.PGTW] based on Dvorak technique satellite intensity estimates andftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081215-WDPN.PGTW] the storm exhibiting tightly-curved convective bands. An upper-level low helped to reduce wind shear that had been affecting the storm. The JTWC also warned of the possibility of rapid intensification. The JMA upgraded the depression to a tropical storm later that day [cite web|author=Japan Meteorological Agency|year=2007|title=Tropical Storm Sepat Tropical Cyclone Advisory|accessdate=2007-08-15|url=http://www.webcitation.org/5R2peQnF7] and named it Sepat , a name contributed by Malaysia referring to a freshwater fish species.cite web|url=http://www.jma.go.jp/jma/jma-eng/jma-center/rsmc-hp-pub-eg/tyname.html|title=Typhoon names]

By early the next morning, August 13, Sepat had a banding eye visible on microwave satellite imageryftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081303-WDPN.PGTW] and had remained in an environment conducive for strengthening, including weakening wind shear. An upper-level anticyclone also moved over the storm. By now, Sepat had moved into PAGASA's area of responsibility and attained the local name "Egay". The JMA upgraded Sepat to a severe tropical storm shortly after. [ftp://ftp.met.fsu.edu/pub/weather/tropical/Tokyo/2007081306.RJTD] Sepat continued to slowly gain more organisation and intensify further,ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081315-WDPN.PGTW] and started to move faster under the influence of a subtropical steering ridge. Sepat strengthened into a typhoon on the morning of August 14 [ftp://ftp.met.fsu.edu/pub/weather/tropical/Tokyo/2007081400.RJTD] [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081403-WTPN.PGTW] under still-decreasing wind shear and favourable diffluence.ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081403-WDPN.PGTW]

Sepat developed a cloud-filled eye measuring 12 nautical miles (22 km, 14 mi) across by later that night, part of a larger central dense overcast nearly 130 nm (240 km, 150 mi) wide.ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081415-WDPN.PGTW] Favourable sea surface temperatures of 29 – 30 °C (84 – 86 °F) allowed Sepat to continue intensifying despite decrease of poleward outflow. By this time, Sepat had deepened to 955 hPa. [cite web|url=http://www.webcitation.org/5R5qN2RuB|title=www.webcitation.org/5R5qN2RuB ] The JTWC also noted possible imminent rapid intensification of the storm.

Late that night, Sepat underwent rapid intensification as expected, and was upgraded by the JTWC to a super typhoon the next morning.ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081503-WDPN.PGTW] The JMA analysed Sepat at 940 hPa at the same time. [ftp://ftp.met.fsu.edu/pub/weather/tropical/Tokyo/2007081500.RJTD] The deep convection warmed slightly and underwent slight fluctuations during the afternoon. [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081509-WTPN.PGTW] During this period, Sepat slowed in forward speed and took a turn from a west-southwest motion to a more poleward one.ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081515-WDPN.PGTW] Its eye also cleared out, became slightly larger, and warmed. By late that night, Sepat had become the strongest storm of the season to date, with the JMA analysing its pressure at 925 hPa, [cite web|url=http://www.webcitation.org/5R7Su6gGk|title=www.webcitation.org/5R7Su6gGk ] lower than Typhoon Man-yi's minimum of 935 hPa.

Continuing to intensify,ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081603-WDPN.PGTW] Sepat reached a peak minimum central pressure of 910 hPa on the morning of August 16. [cite web|url=http://www.webcitation.org/5R7nAjOR1|title=www.webcitation.org/5R7nAjOR1 ] It also managed to maintain its cloud-free eye. High ocean heat content and good equatorward outflow allowed Sepat to maintain its intensity, but an eyewall replacement cycle began later that night.ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081615-WDPN.PGTW] The eyewall replacement cycle continued throughout the night, and by the next morning Sepat displayed concentric eyewalls, with the inner eyewall being weaker. [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081703-WDPN.PGTW] The JTWC downgraded it to a typhoon later that evening. [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081709-WTPN.PGTW]

It made landfall in eastern Taiwan between Taitung and Hualien on the morning of August 18 local time at around 5 a.m. (2100 UTC August 17) [ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2007081803-WDPN.PGTW] and weakened to a minimal typhoon. [cite web|url=http://www.webcitation.org/5RAux0QOD|title=www.webcitation.org/5RAux0QOD ] After crossing the island, Sepat held on to minimal typhoon intensity before weakening to a severe tropical storm that night. [cite web|url=http://www.webcitation.org/5RBaYJ7 DL|title=www.webcitation.org/5RBaYJ7 DL ] It made a second landfall, in China, about 24 hours after landfall on Taiwan and was downgraded to a tropical storm the next morning. It further weakened inland and the JMA issued its final advisory on the morning of August 20.

Preparations

The Government of the Republic of China issued sea typhoon warnings on the morning of August 16 and land warnings later that evening. [cite web|url=http://www.taipeitimes.com/News/front/archives/2007/08/17/2003374547|title=www.taipeitimes.com/News/front/archives/2007/08/17/2003374547 ] At all county and city levels, a typhoon holiday was declared for August 18 in preparation for the storm. [cite web|url=http://tw.news.yahoo.com/article/url/d/a/070817/1/ix7k.html|title=tw.news.yahoo.com/article/url/d/a/070817/1/ix7k.html ] In the Philippines, PAGASA issued Public Storm Warning Signals 1 to 3 (4 is the highest signal) for most provinces of Luzon. [cite web|url=http://www.webcitation.org/5RAATPItm|title=www.webcitation.org/5RAATPItm ]

Over 900,000 people were evacuated in eastern China, and over 100 flights had to be cancelled.cite web|url=http://news.bbc.co.uk/2/hi/asia-pacific/6952715.stm|title=news.bbc.co.uk/2/hi/asia-pacific/6952715.stm ] In Taiwan, nearly 2,000 people had to be evacuated.cite news|url=http://edition.cnn.com/2007/WORLD/asiapcf/08/21/typhoon.sepat.reut/index.html|title= Typhoon Sepat kills 39 in China|date=2007-08-22|accessdate=2007-08-23|publisher=CNN|author=Reuters]

After Sepat made landfall in China, the regional meteorological office in Hunan Province sent over 2.25 million text messages to residents to warn them about the storm's remnants.cite news|url=http://news.xinhuanet.com/english/2007-08/20/content_6569904.htm|title=Typhoon Sepat sweeps NW after killing 19 in SE China|publisher=Xinhua|date=2007-08-20]

Impact

Philippines

On August 15, monsoon rains brought by Typhoon Sepat flooded and paralyzed traffic in Metro Manila. [cite web|url=http://newsinfo.inquirer.net/breakingnews/metro/view_article.php?article_id=82753|title=newsinfo.inquirer.net/breakingnews/metro/view_article.php?article_id=82753 ] Classes and services in government offices were suspended until August 17. [cite web|url=http://newsinfo.inquirer.net/breakingnews/metro/view_article.php?article_id=82675|title=newsinfo.inquirer.net/breakingnews/metro/view_article.php?article_id=82675 ] At least three people drowned.

Taiwan

Sustained winds of 126 km/h (78 mph) were recorded off the Taiwanese coast on August 18 as Sepat moved through the country.

Heavy rainfall in Taiwan, which reached 984 mm (38.7 inches) at Tianhsiang in Hualien,cite web|url=http://www.chinapost.com.tw/news/2007/08/20/119046/Agricultural-losses.htm|title=www.chinapost.com.tw/news/2007/08/20/119046/Agricultural-losses.htm ] resulted in numerous mudslides, especially in mountain regions and in the south while the combination of the precipitation and winds caused an estimated $1.14 billion (2007 NT$, $34.5 million 2007 USD) in agricultural damage. [cite web|url=http://news.xinhuanet.com/english/2007-08/19/content_6563502.htm|title=news.xinhuanet.com/english/2007-08/19/content_6563502.htm ] More than 70,000 homes lost power, and nearly a week after the storm passed through 9,000 people remained without electricity.

The Suao-Hualien Highway was also closed due to landslides brought by the typhoon. One person was reported killed in Taiwan.

Mainland China

In Fujian Province, Sepat's winds felled billboards and ripped roofs off houses and two people were killed, while a tornado was reported in Zhejiang, killing 13 people and injuring at least 60 more. Most counties received almost 200 mm (8 inches) of rainfall. Sepat caused landslides in Fujian, leaving 12 people missing. Landslides were the cause of at least half the 39 deaths in China. Damage was also reported in Jiangxi and Hunan, and damage in the four provinces was estimated at 5 billion yuan (US$658 million).

ee also

* List of notable tropical cyclones
* 2007 Pacific typhoon season

References