The Development Process of Typhoon Lily

200 1 From the end of August, a broad low-pressure belt began to brew in the northern part of the South China Sea, and a weak front system developed, which slowly moved to the northeast. On September 2nd, a weak tropical cloud began to fluctuate in the southeast of the Philippines, and one of them gradually developed into a tropical disturbance, which was temporarily numbered as "95W" by the US Naval Research Laboratory (NRL). At 2pm the next day, joint typhoon warning center (English: JTWC) gave a "weak" rating on its possibility of forming a tropical cyclone within 24 hours. During this period, the system continued to move to the northwest, and gradually approached the southeast sea area of Taiwan Province Island, and soon turned to the northeast.

At 8: 00 am on September 5, it was upgraded to a tropical depression by the Japan Meteorological Agency (JMA) when it reached the southern waters of Ishigaki Island, Japan. Affected by the weak front in the north, the tropical depression continued to move slowly to the north-northwest direction and crossed the eastern sea of Xibiao Island that night. At 8 o'clock that night, the joint typhoon warning center upgraded its rating to "ordinary".

On September 6, after entering the northwest coast of Xibiao Island, it began to turn to the northeast and move slowly due to the influence of a weak front. Due to the gradual improvement of tropical depression structure and increasing power, joint typhoon warning center assessed the tropical cyclone generation opportunity of the system as "excellent" at 3: 30am, and issued a tropical cyclone generation warning (TCFA). At 8 o'clock in the morning, it was upgraded to a tropical storm by the Japan Meteorological Agency on the northern coast of Xibiao Island, numbered "0 1 16" and named "Lily" (English: Nari, Japanese: ナーリー). At the same time, joint typhoon warning center upgraded it to a tropical storm. However, at that time, the wind radius of Lily 7 storm was only about 80 kilometers, which had little impact on the island weather in the surrounding waters.

After being upgraded to a tropical storm by the Japan Meteorological Agency, Lily was still guided by its northern frontal system, and slowly moved to the northeast-east direction, crossing the northern sea of Miyakojima from the afternoon of September 6th to the evening.

12 At midnight on September 7th, the joint typhoon warning center upgraded it to a tropical storm. After that, Lily traveled for a long time in the southern part of Mishima in the early morning, and was upgraded to a severe tropical storm by the Japan Meteorological Agency at 5 am. At about 6: 00 a.m. to 7: 00 a.m. that day, Lily passed the southern tip of Okinawa Island, near the south of Hazama jade City. At 7: 30 in the morning, Lily landed in Kaman City, Okinawa Prefecture. But that morning, the northern front gradually moved away from the northeast and continued to weaken, and the guiding force of Lily suddenly weakened. Therefore, at that time, it did not continue to move away from Okinawa in the east-northeast direction, but began to stagnate east of Naha. That night, the anticyclone in North China gradually approached Taiwan Province Province and Ryukyu Islands, becoming another leading force in Lily's path. As a result, Lily suddenly turned around and began to move to the west-northwest direction, and landed at Beizhongcheng Village, Zhongtou County, Okinawa Prefecture at 3: 30 am on September 8. On the other hand, because Lily's power began to increase gradually, the joint typhoon warning center upgraded it to a typhoon, and the average wind speed in one minute was upgraded to 70 knots, which was equivalent to a typhoon below the safire-Simpson hurricane level. After entering the northwest sea of Ryukyu in the morning, it began to move slowly to the northwest under the weak guidance of the anticyclone in the northern part of the central mainland. At the same time, Typhoon Danas, located in the south-southeast of Japan, continued to move to the west-northwest direction. Due to the wide peripheral air flow field, the magnitude of the southern pressure of the continental anticyclone was slightly enhanced, so Lily began to move to the west-northwest direction at 2 pm that day, and its speed was slightly accelerated. At that time, central weather bureau, Taiwan Province Province (CWB) judged that Lily might pose a threat to the northern waters of Taiwan Province Province, so it issued a typhoon warning in the northern and northeastern waters of Taiwan Province Province at midnight 1 1: 50.

On September 9, due to Danas' stronger strength and wider wind field, lily began to be gradually suppressed. However, because Danas itself is caught in the saddle area between the middle continental high and the subtropical high, it can only move slowly to the west, so Lily is only constrained and its path is still moving slowly to the west-northwest direction. That night, affected by the large-scale wind field of Danas, the northern high pressure range began to press south, and the pressure on lily became more and more obvious. Moreover, due to the weakness of steering flow, Lily suddenly changed direction at 8 o'clock that night and began to move south.

At 8: 00 am on September 10, the power of lily began to show signs of weakening due to the northeast wind accompanied by a little cold advection in the north. On that day, Danas, who was originally trapped in the saddle yard and moved slowly, gradually left the saddle yard because of the eastward movement of the high-altitude trough at high latitude, and began to turn north-northwest to approach kanto region. Lily, restrained by Danas, moved slowly to the east-southeast direction from noon because of its vast external gas field. Due to various factors, central weather bureau City, Taiwan Province Province lifted the typhoon warning at 9 am that day. After that, Lily continued to move slowly to the east-southeast direction and began to approach Okinawa Island and Kumi Island for the third time. At 8 o'clock that night, the direction turned to the east and continued to approach Kumi Island.

At 2 a.m. on September 1 1, Lily was off the coast west of Kumejima, and Dahners, which influenced Lily's direction, began to rapidly turn north to attack Kanto in the north-northeast direction. The guiding force for Lily began to gradually disappear after the early morning of that day, so there was no power to guide Lily at that time. At 8 o'clock in the morning, Lily's power continued to increase, and it was upgraded to typhoon level by Japan Meteorological Agency. The central wind speed increased to 65 knots, and the lowest pressure was 970 hectopascals.

From the morning of September 1 1 to the morning of September 12, Lily has been wandering in the eastern coastal waters of Kumi Island, and its power has been increasing, reaching its first peak at 2 pm on September 1 1, with a central wind speed of 75 knots and a minimum pressure of 960 hectopascals. At the same time, the joint typhoon warning center upgraded its intensity to the upper limit of the second-class typhoon, even to the third-class typhoon at 6 pm, with an average wind speed of 100 knots per minute. But later, the Joint Typhoon Warning Center rated it as a second-class typhoon at midnight on September/KOOC-0/2, and even further rated it as a first-class typhoon at midnight on September/KOOC-0/3, and the Japan Meteorological Agency downgraded it to a severe tropical storm at that morning/KOOC-0//KOOC-0/. /kloc-In the early morning of September, 2003, a high-altitude trough was gradually established in the northeast of Chinese mainland, and the lily was suspected to be in a state of ownerless due to this trough. At 3: 30 in the morning, Lily landed on Kumi Island, Shimashima Prefecture, Okinawa Prefecture. From the morning of September 13 to the morning of September 14, it began to move slowly to the northwest. At this time, however, Danas has dissipated, so the subtropical high can extend westward and establish a center in Hainan, Japan. However, due to the high pressure equivalent to that in Chinese mainland and East China, Lily fell into a new saddle field. Although it moves slowly to the northwest due to the influence of the high-altitude trough, its guiding force is not strong because the trough bottom is still high. At this time, the moving speed of lily is still very slow, and at the same time, due to the tension of airflow, the lily structure can not maintain a good state, and its strength is weakened again. Also due to the return of Lily, central weather bureau, Taiwan Province Province issued a typhoon warning in the northern waters of Taiwan Province Province at 3 pm that day. After that, the lily continued to move slowly to the northwest, and the distance from the bottom of the trough was getting closer and closer. At this time, some forecasting models began to predict that Lily might catch up with the trough line northward, but unexpectedly, the situation changed from the night of September 13.

Because the continental high to the west of Ma 'anchang began to increase gradually and its height increased, and a cold core depression appeared in southern Japan, the subtropical high forces were forced to retreat eastward, while the position of the northern trough line remained unchanged, but the depth did not deepen. Under the influence of various factors, the northeast wind guiding force of the west high began to gain the upper hand gradually, and this phenomenon became more obvious until September 14. At 8 o'clock in the morning, when the center of Typhoon Lily climbed to the northernmost latitude of 27.6 degrees north and east longitude of 125.3 degrees east, its path direction began to change sharply, moving from west-southwest to southwest, and preparing to approach the north and northeast of Taiwan Province Province. According to the middle and high-level flow field map, the guidance center in North China is bringing northeast airflow to Lily, which means that Lily's attack on Taiwan Province Province will become a foregone conclusion. At 2: 45 am on September 15, central weather bureau City, Taiwan Province Province issued a land typhoon warning in the north and northeast of Taiwan Province Province. However, in terms of intensity adjustment, the Joint Typhoon Warning Center downgraded it to a tropical storm at midnight 12 that day, but upgraded it to a typhoon at 8 am, and its intensity rating was equivalent to a first-class typhoon.

The strength of lily began to increase gradually when the airflow traction that caused the deterioration of lily structure had disappeared. Although Lily is not far from the land of Taiwan Province Province at this time, due to the small scope, the radius of strong wind circle is only 150km, and the moving speed is only maintained at about 10km/h, so the influence of Lily on Taiwan Province Province did not gradually appear until after the afternoon of September 15. On the night of September 15, the South China High began to move eastward, and at the same time, the ground high center near North China began to move eastward to Shandong Peninsula, which caused Lily to move at the angle of west-southwest at 7 o'clock that night, which greatly aggravated the threat of Lily to the northern part of Taiwan Province Province. Lily was later upgraded to a typhoon level by the Japan Meteorological Agency at 2 pm on June 5438+05, with a central wind speed of 65 knots and a minimum pressure of 970 hectopascals, and its power is still increasing. According to the satellite cloud picture at that time, its structural development was quite solid, indicating that the water vapor supply was sufficient and the eye of the wind was clearer than before. At the same time, the rain in the northern part of Taiwan Province Province is gradually emerging.

On September 16, Lily continued to approach the land in the northeast corner of Taiwan Province Province from the west-southwest corner, and its intensity continued to increase. At 8: 00 am that day, the Joint Typhoon Warning Center rated it as a second-class typhoon, and its storm radius edge also touched the land in the northeast corner of Taiwan Province Province. At 2 pm, Lily reached the second peak, with a central wind speed of 75 knots and a minimum pressure of 960 hectopascals. At the same time, the direction of lily changed again, which is suspected to be due to the terrain. The angle of the route turned south again, approaching the northeast corner of Taiwan Province Province from southwest to south-southwest, and even stopped off the coast of Sanminkao for two hours from 6 pm to 7 pm. In addition, due to the action of the airflow around the mountain in Taitung County, a significant sub-low pressure center began to appear at night, interacting with the original main center and slowly moving northward along the east coast. At 9: 40 pm, Lily landed in Sandiaojiao, Gongliao Township, Taibei County, Taiwan Province Province, and Tou Town, Yilan County.

Affected by the snow-capped mountains, Lily moved all the way to the southwest along Yanglan Valley, and its structure was quickly destroyed and weakened. On September 17, it suddenly became a tropical storm at midnight, and even further weakened into a tropical depression at 2 pm. At the same time, the joint typhoon warning center was downgraded to a first-class typhoon because of its gradual weakening, and even further downgraded to a tropical storm at 8 am. At 2: 00 a.m. that day, Lily was named "Kiko" because she entered the tropical cyclone responsibility area of the Philippine Atmospheric Geophysical and Astronomical Administration (English: PAGASA) and was rated as a tropical storm. At that time, the moving speed of Lily was obviously slowed down due to the influence of topography, while the sub-center near the east coast of Taiwan Province Province gradually moved northward. However, the high pressure in the north of Lily has moved eastward to the sea, so the guiding force began to weaken, which led to the slow movement of Lily after crossing the mountain. The strength of the sub-center on the east coast of Taiwan Province Province at this time is almost equal to that of the main center. Under the condition of interaction between them, the main center of lily can only slowly go south along the west side of the central mountain range.

From 2: 00 a.m. to 8: 00 a.m. on September 18, the main center of Typhoon Lily has been stagnant near Douliu City, Yunlin County, with little movement. That night, the sub-low pressure center gradually disappeared near Hualien, so Lily got rid of the shackles, so she went south again after 7 pm, and finally went out to sea from Anping District of Tainan City that afternoon 1 1, entered the southern part of the Taiwan Province Strait, and then entered the waters north of the South China Sea. The stagnation time of Lily in Taiwan Province Province is 49 hours and 20 minutes. Lily moved slowly to the south-southwest direction from midnight to afternoon on September 9 12. At midnight 12 that day, the joint typhoon warning center downgraded it to tropical depression. At 2 o'clock in the afternoon, as the anticyclone in the north led the southward pressure again, the subtropical high began to spread westward gradually, so Lily began to move westward gradually, and the speed began to accelerate gradually, so the Philippine Atmospheric Geophysical and Astronomical Administration issued the final warning (1 1), which meant that Lily was gradually moving away from the Philippines. Subsequently, the HKO Observatory hoisted the No.1 alert signal at 4 pm 15 on the same day.

As for central weather bureau, Taiwan Province Province, the land typhoon warning and the sea typhoon warning were lifted at 5 pm and 65: 438+06: 5438+0: 05 pm respectively. That night 10, the Geophysical and Meteorological Bureau (Portuguese: SMG) began to hang the No.1 typhoon signal.

At midnight on September 20th 12, the intensity of Lily began to increase again because the typhoon center entered the sea, so the Japan Meteorological Agency and the Joint Typhoon Warning Center upgraded it to a tropical storm at the same time, which was the third enhancement in Lily's life history. At 8: 00 a.m. on the same day, Lily continued to move rapidly to the west-northwest and approached the eastern coastal area of Guangdong Province, China, but the Japanese Meteorological Agency downgraded Lily to a tropical depression at 2: 00 p.m. With Lily approaching, the Hong Kong Observatory and the Macau Geophysical and Meteorological Bureau hoisted the No.3 strong wind signal and No.3 typhoon signal at 2: 45 p.m. and 6: 00 p.m. respectively. However, Lily's route is slightly northwest than originally expected. It landed at Jiadong Town, Lufeng City, Shanwei City, Guangdong Province, China at about 4 pm that day, and then continued to move to the west-northwest direction. After Lily left, the Hong Kong Observatory lowered all tropical cyclone warning signals at 22: 40 that night. After landing, the intensity also weakened rapidly, and weakened to the lower limit of tropical storm around 1 1 that night, and its wind circle gradually narrowed.

Finally, after Lily was downgraded to a tropical depression by the Joint Typhoon Warning Center at midnight on September 2 1, the Macau Geophysical and Meteorological Bureau cancelled all tropical cyclone signals at 2: 30 am. At 8 o'clock in the morning, Lily entered the east of Guangxi. At the same time, the Joint Typhoon Warning Center issued the final warning (No.61). After that, its circulation gradually dissipated at 2 pm that day, announcing the official end of its life history of 17 days and 6 hours.