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TC Watch / 熱帶氣旋 > Selected TC Review / 重要熱帶氣旋回顧 > 202113W (LUPIT 盧碧) [Refresh 更新]

202113W (LUPIT 盧碧) - Profile 檔案

(First draft issued on August 19, 2021, final version issued on October 17, 2021)
(初稿於 2021 年 8 月 19 日發出,最後版本於 2021 年 10 月 17 日上載)

Brief profile of LUPIT | 盧碧小檔案:

JTWC number 聯合颱風警報中心 (JTWC) 號碼 13W
International number 國際編號 2109
Period of existence 生存時期^ 2021/08/02 20 HKT - 2021/08/11 02 HKT
Maximum 1-minute wind (JTWC) JTWC 一分鐘平均最高中心風速

55 knots 節 (Severe Tropical Storm equivalent 相當於強烈熱帶風暴級)

Minimum pressure (JTWC) JTWC 最低氣壓 976 hPa 百帕
Highest TC signal by HKO
香港天文台發出最高熱帶氣旋警告信號
3 (Strong Wind Signal 強風信號)
Closest point of approach by HKO
香港天文台所示之最接近距離
SSW 120 km (real-time warning 實時報告) / 110 km (TC report 熱帶氣旋報告)
Time of closest approach by HKO
香港天文台所示之最接近時間
2021/08/03 17-18 HKT (real-time warning 實時報告) / 14 HKT (TC report 熱帶氣旋報告)
Lowest pressure recorded at HKO
香港天文台錄得的最低氣壓
993.0 hPa 百帕 (2021/08/04 16:21 HKT)

^Refers to the period between the HK Observatory's first and last bulletins for the tropical cyclone (with at least tropical depression intensity). For storms formed/dissipated/transformed into an extratropical cyclone outside the area bounded by 7-36°N and 100-140°E, information from the JTWC will be used instead.
^即香港天文台為該熱帶氣旋 (熱帶低氣壓級或更高) 作出發佈的時期。至於在北緯 7 至 36 度、東經 100 至 140 度外形成/消散/轉化為溫帶氣旋的風暴,本網將參考聯合颱風警報中心的資料。

TC signals in Hong Kong* 香港曾經生效的熱帶氣旋警告*:

Signal
信號
Date and time
日期和時間
Distance from HK
與香港的距離
Predicted movement
預測移動趨勢
Max. 10-min winds
中心最高十分鐘平均風速
2021/08/02 (MON) 21:40 HKT SW 270 km E at 12 km/h 45 km/h (25 knots, TD)
2021/08/03 (TUE) 16:25 HKT SSW 120 km E slowly 55 km/h (30 knots, TD)
2021/08/04 (WED) 04:20 HKT SSE 160 km E slowly → NE at 12 km/h 55 km/h (30 knots, TD)
2021/08/04 (WED) 18:20 HKT ESE 220 km NE at 12 km/h 65 km/h (35 knots, TS)

*Based on the information from real-time tropical cyclone warning bulletins.
*根據實時熱帶氣旋警報資料。

Percentile Ranks 百分等級:

Percentile rank among storms with #3 Signal (at compilation of this review)*:
發出三號信號之風暴中的百分等級 (編寫此回顧之時)*:

*This measures the relative wind strength in Hong Kong caused by this storm compared with others that share the same signal. 指標顯示此風暴相對於其他發出同樣信號的風暴為香港帶來之風力強度

For more information, please refer to Wind Speed Data for TCs that Have Affected Hong Kong. 更多資訊載於 影響香港氣旋之風速數據

  Overall:
總計:
5
  Weak
Component Ranks 分部等級
  Reference stations:
參考站:
0
  Weakest
最弱
  Victoria Harbour:
維多利亞港:
15
  Weak
  Urban:
市區:
3
  Weak
  Offshore & high ground
離岸和高地:
4
  Weak

Cyclones that attained similar rating (with signal #3): SAUDEL (2020), YUTU (2018), MARIAN (1990)
相近級別之熱帶氣旋 (三號信號):沙德爾 (2020)、玉兔 (2018)、瑪麗安 (1990)

IR imagery animation 紅外線雲圖動畫:

TC track from HKWW 本站的熱帶氣旋路徑圖:

TC Track

TC track from HKO 天文台的熱帶氣旋路徑圖:

TC Track

TC Track

Past HKWW Bulletins 本站發佈

Please click here for bulletins on this tropical cyclone. 請按這裡

Storm Development Overview 風暴發展概覽

Unless otherwise stated, all times below are in Hong Kong Standard Time (UTC+8)
除非特別註明,下文時間均為香港標準時間 (協調世界時加 8 小時)

The convergence of an active southwest monsoon in the South China Sea and the northeasterly winds from a continental ridge led to the formation of a cyclonic system (tropical disturbance 90W) near the Leizhou Peninsula in early August. The NMC upgraded 90W into a tropical depression at 5 pm August 2 as its convections developed. The HKO followed suit at 8 pm, while the JTWC issued a tropical cyclone formation alert. By the time of the upgrade, 90W had moved into northern South China Sea just south of western Guangdong. Numerical models generally predicted that 90W would move east and then turn to the northeast along the northern periphery of the equatorial ridge in the South China Sea, thus staying close to the southeastern Chinese coastal areas.

90W's convections expanded during the night of August 2, especially in its southern semicircle. Radar images also showed that 90W had a well-defined circulation centre surrounded by spiraling rainbands. The JTWC upgraded 90W into tropical depression 13W in the small hours of August 3, while the JMA issued a gale warning in the morning that day. 90W dipped southwards slightly over the day as it passed to the south of Hong Kong. 90W's circulation continued to expand that night as the system benefited from the southwesterly airstream. It was upgraded by various agencies into a tropical storm in the morning of August 4, with the JMA naming it LUPIT.

LUPIT turned northeast in the afternoon of August 4 and approached eastern Guangdong. Some numerical models, most notably GFS, suggested the possibility that a weak ridge would develop between LUPIT and another storm MIRINAE in the Pacific, and that LUPIT would turn northwest after it made landfall. LUPIT turned almost due north on August 5, and the NMC reported that it made landfall near Nan'ao county in Shantou, Guangdong at around 11:20 am. However, instead of digging deeper inland, LUPIT moved along the coast and another landfall was registered at 4:50 pm near Zhangzhou in Fujian province. Various official agencies showed disagreement on LUPIT's intensity forecast. Some agencies believed that LUPIT would not survive upon landfall, while others brought the system back into the East China Sea or Taiwan Strait as the storm continued to move northeast.

LUPIT moved somewhat erratically near the Fujian coast but generally remained on a northeasterly course. It weakened slightly, with the NMC and HKO downgrading it into a tropical depression briefly on August 6. The storm turned east and crossed the Taiwan Strait during the night of August 6 and the morning of August 7. Taiwan's terrain disrupted LUPIT's structure; in response, LUPIT developed another centre to the northeast on August 7.

Following the southwesterly airstream and moving along the northwestern periphery of the equatorial ridge, LUPIT accelerated towards the northeast, moving across the East China Sea on August 8 and intensifying slightly. The storm started to encounter higher vertical wind shear as it neared Japan; much of its deep convections were displaced to the northeast. LUPIT made landfall near Kagoshima and crossed western Japan that night, before moving into the Sea of Japan in the morning of August 9. It transformed into an extratropical cyclone later that day while crossing the Sea.

8 月初,由於南海的西南季候風及與大陸高壓脊相關的東北風匯聚,熱帶擾動 90W 於雷州半島一帶形成。隨著其對流發展,中國中央氣象台於 2 日下午 5 時將 90W 升格為熱帶低氣壓。香港天文台於下午 8 時跟隨,而聯合颱風警報中心則發出熱帶氣旋形成警報。升格 90W 之時,它已移至廣東西部以南的南海北部。電腦數值模式普遍預料 90W 將沿南海赤道高壓脊的北部向東、後轉東北移動,與中國東南沿岸維持較接近的距離。

90W 的對流於 8 月 2 日晚擴展,尤其是於風暴南半圓,而雷達圖像亦顯示 90W 有一清晰、被螺旋雨帶圍繞著的環流中心。聯合颱風警報中心於 3 日凌晨將 90W 升格為熱帶低氣壓 13W,而日本氣象廳則於早上發出烈風警告。13W 當天橫過香港以南,期間稍為南移。受惠於西南氣流,13W 的對流於晚間繼續擴展,它於 4 日上午被各氣象機構升格為熱帶風暴,日本氣象廳將其命名為盧碧。

盧碧於 8 月 4 日下午轉向東北移動,趨向廣東東部。部分數值模式如 GFS 預測盧碧與位於太平洋的另一氣旋銀河之間會有一弱脊場建立,令盧碧登陸後向西北移動。盧碧於 5 日轉向偏北移動,中央氣象台表示風暴於上午約 11 時 20 分在廣東汕頭市南澳縣一帶登陸。但是,盧碧未有進一步深入內陸,而是沿岸邊進發,並於下午約 4 時 50 分在福建漳州附近再度登陸。各官方機構對於盧碧的強度預測出現分歧,部分預計盧碧登陸後將減弱消散,其他的則預計風暴繼續向東北移動,並將進入東海或台灣海峽。

盧碧於福建沿岸大致向東北移動,但間中移向不規則。風暴稍為減弱,中央氣象台及香港天文台均曾於 8 月 6 日短暫將其降格為熱帶低氣壓。盧碧於 6 日晚及 7 日早上向偏東移動,並橫過呂宋海峽。台灣的地形影響盧碧的結構,風暴於其東北方建立另一中心。

8 月 8 日,盧碧沿著西南氣流及赤道高壓脊的西北部向東北加速,橫過東海並稍為增強。風暴靠近日本時進入較高垂直風切變的環境,其大部分深層對流被切離至東北方。盧碧當晚於鹿兒島一帶登陸,並橫過日本西部。它於 9 日早上進入日本海,並於當天較後時間轉化為溫帶氣旋。

Weather in Hong Kong During Approach 風暴影響時香港天氣狀況

Link to relevant HKO weather report bulletins: 2/83/84/8
香港天文台相關天氣報告連結2/83/84/8

In the afternoon of August 2, the HKO indicated that the #1 Standby Signal would be considered that night or in the next morning as LUPIT might develop gradually. The signal was issued at 9:40 pm that night, around 1 hour after the HKO upgraded LUPIT into a tropical depression. LUPIT was situated around 270 km southwest of Hong Kong at that time.

The local weather was unstable on August 2 and 3 with occasional showers. LUPIT moved more northwards than predicted in the small hours of August 3, and was within 150 km of the territory in the morning. Winds strengthened from the east in the morning of August 3, but due to LUPIT's small circulation, the HKO maintained that the #1 Signal would remain in force for most of the daytime unless it moved unexpectedly close or strengthened significantly.

At around 2 pm August 3, the HKO changed its decision and predicted an increase in the general wind level over Hong Kong that night. The #3 Standby Signal was issued at 4:25 pm, when LUPIT was around 120 km south-southwest of Hong Kong. However, at most places the strongest winds during LUPIT's approach were recorded in the early afternoon of August 3. This was when LUPIT's northern outer rainbands affected the territory while it was still relatively close. After the #3 Signal was issued, local winds actually diminished during the night as LUPIT took an east-southeasterly course, thus receding from Hong Kong. The fact that LUPIT moved from west to east also meant that winds in Hong Kong backed from east to north, a more sheltered direction.

During the period of time when the #3 Signal was in force, strong winds were confined to offshore waters such as Cheung Chau, Green Island and Waglan Island, and at elevated locations such as Ngong Ping and Tate's Cairn. As LUPIT moved away gradually, the HKO replaced the #3 Signal by the #1 Standby Signal at 4:20 am August 4. While LUPIT was still within 200 km of the territory, local winds were rather weak. There was however a spike in wind speed near 3 pm that day, as a spiraling arm of LUPIT's rainband swept across Hong Kong. Heavier rain fell towards the evening; the Amber Rainstorm Warning was in force between 5:10 pm and 10:15 pm.

Winds returned to a light to moderate level near dusk; the #1 Signal was cancelled at 6:20 pm, when LUPIT was around 220 km east-southeast of Hong Kong. Over 30 mm of rain fell over most parts of the territory during August 4, while parts of the northern New Territories received over 100 mm. Due to the active southwesterly airstream enhanced by LUPIT, the local weather remained unstable over the next couple of days, and the Red Rainstorm Warning was in force during the small hours of August 6.

8 月 2 日下午,香港天文台表示盧碧可能會發展,將考慮於晚間或翌日早上發出一號戒備信號。該信號於下午 9 時 40 分發出,即天文台將盧碧升格為熱帶低氣壓後約 1 小時,當時盧碧集結於香港西南約 270 公里。

香港 8 月 2 及 3 日天氣不穩定,間中有驟雨。3 日凌晨,盧碧的移向較預期偏北,至早上已進入本港 150 公里範圍。早上東風增強,但由於盧碧環流較細,天文台仍然表示除非風暴較預期接近香港或顯著增強,否則一號信號將於日間大部分時間維持。

至 8 月 3 日下午約 2 時,天文台預測有所改變,指出當晚本港風勢會有所增強。三號強風信號於下午 4 時 25 分發出,當時盧碧位於香港西南偏南約 120 公里。可是,本港多處已於 3 日下午早段、盧碧仍然較接近香港而其北部外圍雨帶掠過時錄得最高風速。三號信號發出後,由於盧碧向東南偏東移動並移離本港,晚間風勢不升反跌。而且,由於盧碧由西向東移動,香港的風向由偏東逆轉至偏北,屏蔽相對較大。

三號信號生效期間,強風局限於離岸如長洲、青洲、橫欄島,以及高地如昂坪及大老山等。隨著盧碧逐漸移離,天文台於 8 月 4 日上午 4 時 20 分改發一號戒備信號,取代三號強風信號。雖然盧碧仍於香港 200 公里內,但本地風勢偏弱;盧碧的雨帶旋臂於下午約 3 時掃過香港,部分地區風勢短暫增強。當天傍晚雨勢加劇,黃色暴雨警告於下午 5 時 10 分至 10 時 15 分生效。

日落前後,本港風勢普遍回復至輕微至和緩水平。天文台於下午 6 時 20 分取消一號戒備信號,當時盧碧位於香港東南偏東約 220 公里。8 月 4 日本港大部分地區錄得超過 30 毫米雨量,新界北部更錄得超過 100 毫米。由於盧碧令西南氣流更趨活躍,其後數天香港天氣仍然不穩定,6 日凌晨更曾發出紅色暴雨警告。

Image Gallery 圖片庫

Figure 1 - Satellite image of LUPIT on August 3 (left) and 5 (right)
圖 1 - 8 月 3 日 (左) 及 5 日 (右) 盧碧之衛星雲圖

Figure 2 - LUPIT's centre and circulation seen on HKO's 128-km radar image
圖 2 - 盧碧的中心及環流於香港天文台之 128 公里範圍雷達圖中可見

Figure 3 - Wind field analysis at 8:01 am August 4 (left) and 8:38 am August 7 (right)
圖 3 - 8 月 4 日上午 8 時 01 分 (左) 及 7 日上午 8 時 38 分 (右) 之風場掃描

Figure 4 - GFS ensemble forecast on August 4 [Image from Tropical Tidbits]
圖 4 - 8 月 4 日之 GFS 模式集成預報圖 [圖像取自 Tropical Tidbits]

Figure 5 - Forecast tracks from various official agencies on August 5
圖 5 - 8 月 5 日各官方氣象台之預測路徑

Figure 6 - Steering flow chart at 8 am August 6 (The low pressure systems from left to right are: LUPIT, MIRINAE, 12W, and NIDA)
圖 6 - 8 月 6 日上午 8 時之駛流場分佈圖 (各低壓系統從左至右依次為盧碧、銀河、12W 及妮妲)

Figure 7 - Satellite image of LUPIT on August 6 showing the intense convections in its southern periphery
圖 7 - 盧碧於 8 月 6 日之衛星雲圖,其南部有猛烈對流

Figure 8 - Satellite image of LUPIT crossing the East China Sea
圖 8 - 盧碧橫過東海時之衛星雲圖

Figure 9 - Radar images at 6-hour intervals from 5 am August 3 to 11 am August 4
圖 9 - 8 月 3 日上午 5 時至 4 日上午 11 時每 6 小時之雷達圖

Figure 10 - Local wind distribution maps at 6-hour intervals from 5 am August 3 to 11 am August 4
圖 10 - 8 月 3 日上午 5 時至 4 日上午 11 時每 6 小時之本港風勢分布圖

Figure 11 - Wind speed time series at Cheung Chau (top) and Green Island (bottom) on August 3
圖 11 - 長洲 (上) 及青洲 (下) 於 8 月 3 日之風速時間序列圖

Figure 12 - Rainfall distribution maps for August 4 (left) and 6 (right)
圖 12 - 8 月 4 (左) 及 6 日 (右) 之雨量分佈圖

Winds Recorded at Reference Stations 參考站所錄得的風速

The following table lists the maximum 10-minute average (sustained) wind speed recorded while tropical cyclone signals were in force. In some occasions, it is possible that the strongest winds were not recorded when the highest signal was in force.

下表列出各站於熱帶氣旋警告信號生效時所錄得的最高 10 分鐘平均 (持續) 風速,留意此風速不一定於最高信號生效期間錄得。

Station
風速站
Max. 10-min avg. wind speed
最高十分鐘平均風速
Beaufort classification
蒲福氏風級分類
Chek Lap Kok 赤鱲角 36 km/h Fresh 清勁
Cheung Chau 長洲 47 km/h STRONG 強風
Kai Tak 啟德 Below "fresh" threshold of 31 km/h 低於「清勁」下限的 31 km/h
Lau Fau Shan 流浮山 48 km/h STRONG 強風
Sai Kung 西貢 32 km/h Fresh 清勁
Sha Tin 沙田 Below "fresh" threshold of 31 km/h 低於「清勁」下限的 31 km/h
Ta Kwu Ling 打鼓嶺 Below "fresh" threshold of 31 km/h 低於「清勁」下限的 31 km/h
Tsing Yi (SHL) 青衣蜆殼油庫 Below "fresh" threshold of 31 km/h 低於「清勁」下限的 31 km/h

Number of stations recording at least STRONG force (force 6 - 7) winds: 2
Number of stations recording at least GALE force (force 8 - 9) winds: 0
Number of stations recording at least STORM force (force 10 - 11) winds: 0
Number of stations recording HURRICANE force (force 12) winds: 0

錄得 強風 (6 - 7 級) 或更高風速的站數: 2
錄得 烈風 (8 - 9 級) 或更高風速的站數: 0
錄得 暴風 (10 - 11 級) 或更高風速的站數: 0
錄得 颶風 (12 級) 風速的站數: 0

Charts and Figures 各項數據

Table 1: Track data from HKWW:
表一 : 香港天氣觀測站之路徑資料

YYMMDDZZ Lat Long Wind
21080206 210N1106E 025
21080212 208N1118E 025
21080218 210N1127E 025
21080300 213N1134E 030
21080306 214N1137E 035
21080312 212N1142E 035
21080318 210N1147E 035
21080400 212N1155E 035
21080406 215N1158E 040
21080412 217N1163E 040
21080418 224N1168E 045
21080500 231N1168E 045
21080506 235N1169E 045
21080512 238N1173E 040
21080518 242N1174E 040
21080600 245N1181E 035
21080606 249N1187E 035
21080612 251N1193E 035
21080618 251N1198E 035
21080700 249N1204E 040
21080706 258N1229E 040
21080712 268N1243E 040
21080718 284N1253E 040
21080800 292N1268E 040
21080806 300N1278E 040
21080812 315N1307E 045
21080818 339N1326E 045
21080900 350N1331E 045
21080906 364N1351E 045
21080912 374N1361E 040

Table 2: Maximum gust and hourly average wind speed recorded in Hong Kong from HKO:
表二 : 香港天文台公佈的各站最高每小時平均風力和陣風數據 (英文)

Maximum Gust
Maximum Hourly Mean Wind
Direction
Speed (km/h)
Date/Month
Time
Direction
Speed (km/h)
Date/Month
Time
Central Pier WNW 47 4/8 14:47 E 26 3/8 14:00
Cheung Chau NW 71 4/8 14:35 ESE 37 3/8 16:00
Cheung Chau Beach ENE 65 3/8 14:02 E 39 3/8 16:00
ENE 65 3/8 14:04
Green Island NNW 66 4/8 14:34 ENE 44 3/8 15:00
Hong Kong International Airport NW 50 4/8 14:13 E 30 3/8 16:00
Kai Tak E 40 3/8 14:13 E 20 3/8 15:00
King's Park ENE 37 3/8 13:54 E 16 3/8 14:00
E 16 3/8 16:00
Lamma Island NW 59 4/8 14:42 WNW 32 4/8 15:00
Lau Fau Shan NNW 67 4/8 13:56 E 26 3/8 16:00
Ngong Ping ESE 74 3/8 15:34 E 51 3/8 16:00
North Point WSW 47 4/8 15:05 E 26 3/8 14:00
Peng Chau NNW 58 4/8 14:29 E 33 3/8 16:00
Ping Chau ENE 25 3/8 13:19 E 10 3/8 14:00
E 10 3/8 15:00
Sai Kung NNE 53 4/8 16:40 ENE 24 3/8 14:00
Sha Chau NNW 62 4/8 14:10 ESE 27 3/8 16:00
Sha Lo Wan E 46 3/8 14:55 E 19 3/8 16:00
Sha Tin ENE 32 3/8 17:05 NNE 12 3/8 13:00
Star Ferry (Kowloon) WNW 49 4/8 15:09 W 23 4/8 15:00
Ta Kwu Ling ESE 33 3/8 17:00 E 14 3/8 16:00
E 14 3/8 19:00
Tai Mei Tuk E 51 3/8 15:03 E 33 3/8 16:00
Tai Mo Shan ENE 66 3/8 22:53 ENE 49 3/8 23:00
Tai Po Kau E 42 3/8 12:56 E 26 3/8 16:00
Tap Mun East ESE 48 3/8 16:30 ESE 35 3/8 19:00
Tate's Cairn ESE 60 3/8 14:58 ESE 39 3/8 16:00
Tseung Kwan O SE 34 3/8 14:06 NNE 3 3/8 14:00
Tsing Yi Shell Oil Depot NW 43 4/8 14:20 NNW 17 4/8 07:00
Tuen Mun Government Offices WNW 42 4/8 14:02 WNW 12 4/8 14:00
Waglan Island E 61 4/8 00:22 E 41 3/8 19:00
Wetland Park NNW 32 4/8 14:00 E 12 3/8 16:00
Wong Chuk Hang - 44 3/8 18:22 - 14 3/8 19:00

Table 3: Rainfall (in millimetres) contributed by LUPIT from HKO (figures in brackets are based on incomplete hourly data):
表三 : 香港天文台公佈的各站雨量資料 (英文) (方括號內之數據由不完整之每小時資料擷取)

02-Aug
03-Aug
04-Aug
05-Aug
Total Rainfall
(mm)
Hong Kong Observatory (HKO)
Trace
19.7
41.9
28.1
89.7
Hong Kong International Airport (HKA)
Trace
21.9
48.1
11.9
81.9
Cheung Chau (CCH)
0.0
7.0
51.5
17.0
75.5
H23 Aberdeen
0.0
22.0
38.5
45.5
106.0
N05 Fanling
0.0
13.0
87.0
17.5
117.5
N13 High Island
0.0
11.0
33.0
16.5
60.5
K04 Jordan Valley
0.0
35.5
52.5
20.0
108.0
N06 Kwai Chung
0.0
14.5
56.5
19.0
90.0
H12 Mid Levels
0.5
17.0
58.0
64.0
139.5
N09 Sha Tin
8.5
31.0
45.5
16.5
101.5
H19 Shau Kei Wan
0.5
19.5
60.0
43.0
123.0
SEK Shek Kong
0.0
9.5
[97.0]
15.5
[122.0]
K06 So Uk Estate
0.0
19.5
44.0
24.0
87.5
R31 Tai Mei Tuk
3.0
21.0
59.0
17.0
100.0
R21 Tap Shek Kok
0.0
12.5
65.5
12.0
90.0
N17 Tung Chung
0.0
25.0
50.5
25.5
101.0
TMR Tuen Mun Reservoir
0.0
4.5
85.8
12.0
102.3

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