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TC Watch / 熱帶氣旋 > Selected TC Review / 重要熱帶氣旋回顧 > 202314W (KOINU 小犬) [Refresh 更新]

202314W (KOINU 小犬) - Profile 檔案

(First draft issued on October 21, 2023, final version issued on May 9, 2024)
(初稿於 2023 年 10 月 21 日發出，最後版本於 2024 年 5 月 9 日上載)

Brief profile of KOINU | 小犬小檔案:

^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
	2023/10/04 (WED) 21:40 HKT	E 790 km	W at 12 km/h	175 km/h (95 knots, ST)
	2023/10/06 (FRI) 17:40 HKT	ESE 250 km	W at 12 km/h	145 km/h (80 knots, T)
	2023/10/08 (SUN) 12:40 HKT	SSE 90 km	W/WNW slowly	145 km/h (80 knots, T)
	2023/10/08 (SUN) 19:00 HKT	S 70 km	NW/WNW slowly	140 km/h (75 knots, T)
	2023/10/08 (SUN) 23:50 HKT	SSW 70 km	W/WNW slowly	145 km/h (80 knots, T)
	2023/10/09 (MON) 11:40 HKT	WSW 160 km	WSW at 12 km/h	90 km/h (50 knots, STS)
	2023/10/09 (MON) 14:40 HKT	WSW 190 km	WSW at 12 km/h	85 km/h (45 knots, TS)
	2023/10/09 (MON) 16:20 HKT	WSW 210 km	SW at 14 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:

IR imagery animation 紅外線雲圖動畫:

Radar animation 雷達圖動畫:

TC track from HKWW 本站的熱帶氣旋路徑圖:

TC track(s) from HKO 天文台的熱帶氣旋路徑圖:

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)

An area of low pressure developed in the northwest Pacific Ocean east of the Philippines in late September. This disturbance, then known as 93W, showed signs of intensification on September 29. The JTWC issued a tropical cyclone formation alert that morning, while a gale warning was issued by the JMA in the afternoon. 93W's convections expanded in size but were mostly confined to the southwestern quadrant of the system because of the moderate level of vertical wind shear in that region. The HKO upgraded it into a tropical depression in its weather report at 4:15 pm. The JTWC also upgraded the system that night, giving it the storm number 14W. While 14W was moving westwards at that time, the subtropical ridge to the north was expected to be weakened by a passing mid-latitude trough. This would allow 14W to turn northwest to north-northwest. There were some significant differences in numerical model outputs, as it was not yet known whether the ridge would recover in time for 14W to turn back to the west. The ECMWF and UKMO models were among the first to predict a westward turn after 14W gained some latitude.

Further consolidation took place in the small hours of September 30. While still displaced, 14W's convections started to develop closer to its centre. The JMA upgraded 14W into a tropical storm at 2 am that day, and named it KOINU. As expected, the ridge weakened and KOINU took a northwestward turn. Its convective signature improved gradually in the next few days as the level of vertical wind shear decreased. KOINU intensified into a severe tropical storm early on October 1 and further into a typhoon later that day to early October 2. By daybreak, a banding eye could be seen near KOINU's centre.

The previously divergent numerical model results have also seemed to have agreed on KOINU's track by that point, at least for the next 72 hours or so. The storm was expected to turn west again, moving towards southern or central Taiwan. However, there was still substantial uncertainty on its track after entering the Taiwan Strait. There, the ridge was predicted to weaken again, and the timing would coincide with the strengthening of the northeast monsoon. This resulted in huge variability in both KOINU's track and intensity forecasts. The prevailing forecast at that time and in the next few days was that KOINU would slow down as it moved westwards towards southern China, with a turn to the southwest before it reached land due to the northeast monsoon, together with a decrease in its intensity.

KOINU moved somewhat irregularly between October 2 and October 4. An initial deflection to the west-northwest was compensated by a period of movement to the north-northwest on October 3, leading to an overall movement towards the northwest. On October 4, KOINU turned west and its core developed further. Its eye became clearer and the central dense overcast became larger in size. That night, the island of Lanyu was hit by KOINU's intense western eyewall. A maximum gust of 95.2 m/s (343 km/h) was recorded at 9:53 pm, surpassing the previous record of 89.8 m/s (323 km/h) recorded in 1984. Even higher values were recorded before the equipment went out of service, but those were deemed unreliable. Various official agencies revised their intensity estimations upwards over the night; just before KOINU reached Taiwan on October 5, the estimated intensities were: JTWC - 120 knots (222 km/h); JMA - 90 knots (167 km/h); NMC - 55 m/s (198 km/h); CWA - 48 m/s (173 km/h); HKO - 175 km/h.

Radar images from Taiwan showed that KOINU briefly made landfall at around 8:20 am October 5, near Hengchun at the southern tip of the island. The landfall lasted less than 10 minutes. KOINU's structure deteriorated as it entered northeastern South China Sea; while its eye was still visible on satellite and radar images, the storm shrank significantly in size and the convections near its eyewall became much less intense. KOINU weakened into a minimal typhoon that night and continued to travel westwards on October 6. Due to the high sea temperatures in the South China Sea, KOINU regained strength and its eye became clear again. The compact size allowed the storm to remain largely unaffected by the northeast monsoon.

KOINU decelerated and moved southwestwards briefly in the small hours of October 7. The storm was positioned within a pressure col; it remained slow-moving and started to move west-northwest that day, apparently as a result of a slight development of the ridge to its east. It continued to move west to west-northwest on October 8, with a more significant northward track component that afternoon. As KOINU moved towards the Pearl River Estuary, the storm shrank further and its southern eyewall started to collapse near midnight October 9.

KOINU managed to turn west before impacting land, and crossed the seas just south of the Pearl River Estuary early on October 9. It weakened to below typhoon strength and turned west-southwest in the morning. The storm crossed the Shangchuan Island before weakening into a tropical storm that afternoon. Affected by the northeast monsoon and due to its proximity to land, KOINU's convections dissipated rather quickly and it weakened into an area of low pressure that night. The JTWC continued to track the system and its final bulletin in the morning of October 10 indicated a landfall at the Leizhou Peninsula.

一個低壓區於 9 月下旬在菲律賓以東的西北太平洋發展。這個編號為 93W 的熱帶擾動於 29 日有跡象增強，聯合颱風警報中心於當天早上對其發出熱帶氣旋形成警報，而下午日本氣象廳亦發出烈風警告。當天 93W 的對流有所擴展，但受制於該區的中等垂直風切變，對流主要集中於系統的西南象限。香港天文台於下午 4 時 15 分的天氣報告中將其升格為熱帶低氣壓。聯合颱風警報中心亦於當晚作出升格，並給予風暴編號 14W。雖然 14W 當時向偏西移動，但預料北方的副熱帶高壓脊將會受西風槽打擊而減弱，令 14W 轉向西北至西北偏北。由於不確定副高能否趕及復原從而令 14W 再次西轉，數值模式結果出現明顯分歧。ECMWF (歐洲中期天氣預報中心) 及 UKMO (英國氣象局) 數值模式是較早預測 14W 北移至較高緯度後會轉回偏西移動的模式。

至 9 月 30 日凌晨，14W 進一步整合。雖然 14W 的對流仍有所偏離，但已開始在較為接近中心的位置發展。日本氣象廳於當天上午 2 時將 14W 升格為熱帶風暴，並命名為小犬。一如預期，副高當天有所減弱，而小犬開始向西北移動。隨著垂直風切變水平下降，小犬的對流特徵於隨後數天逐漸改善。風暴於 10 月 1 日早段增強為強烈熱帶風暴，並於當天較後時間至 2 日早段進一步增強為颱風。至破曉時份，小犬的中心可見一雲捲風眼。

而先前出現重大分歧的數值模式亦對小犬未來約 72 小時的路徑有一定共識，預料風暴將西轉並趨向台灣南至中部。但是，風暴進入台灣海峽後的趨勢仍然有很大變數。預料副高屆時會再度減弱，而東北季候風亦於此時增強，這對小犬的路徑及強度預測均構成挑戰。當時及其後數天的主流預報顯示，小犬將於西移至華南期間減速，並因東北季候風影響而於登陸前轉向西南移動，強度有所減弱。

小犬於 10 月 2 至 4 日的路徑較不規則，它初時向西北偏西移動，但 3 日開始向西北偏北移動，整體來說移向大致為西北。小犬於 4 日再度西轉，其核心進一步發展。小犬的風眼漸轉清晰，中心密集雲區擴大。當晚，小犬較為猛烈的西部眼壁掠過蘭嶼島，當地於下午 9 時 53 分錄得最高陣風達每秒 95.2 米 (每小時 343 公里)，打破於 1984 年錄得的每秒 89.8 米 (每小時 323 公里)。蘭嶼島風速計停止運作前曾錄得更高的風速，但被認為其可信度較低。晚間各官方氣象台均上調其強度估計；小犬於 5 日登陸台灣前，各台估計強度為：聯合颱風警報中心 - 120 節 (每小時 222 公里)；日本氣象廳 - 90 節 (每小時 167 公里)；中國中央氣象台 - 每秒 55 米 (每小時 198 公里)；台灣中央氣象署 - 每秒 48 米 (每小時 173 公里)；香港天文台：每小時 175 公里。

台灣的雷達圖顯示小犬於 10 月 5 日上午 8 時 20 分左右在該島南端的恆春一帶登陸，少於 10 分鐘後重新入海。小犬進入南海東北部時結構轉差；雖然從衛星雲圖及雷達圖上仍然可見其風眼，但風暴明顯縮小，眼壁周邊的對流亦有所減弱。小犬當晚減弱至接近颱風強度下限，並於 6 日繼續西移。由於南海海溫較高，小犬重新增強，風眼亦再度變得清晰。小犬緊密的結構令東北季候風影響對其的影響甚小。

小犬於 10 月 7 日凌晨減速並短暫向西南移動，風暴當時正處於氣壓鞍場，移速較低。其東面的脊場當日似乎有所增強，令小犬開始向西北偏西移動。它於 8 日繼續向西至西北偏西移動，下午路徑偏北分量較為明顯。隨著小犬移近珠江口，風暴進一步縮小，南部眼牆於 9 日近午夜時份開始崩潰。

小犬於登陸前成功西轉，並於 10 月 9 日早段橫過珠江口以南海域。它於上午減弱至颱風強度以下，並轉向西南偏西移動，橫過上川島。風暴下午減弱為熱帶風暴，而受東北季候風及華南地形影響，小犬的對流消散速度較快，當晚減弱為熱帶低氣壓。聯合颱風警報中心繼續追蹤小犬的位置，並於 10 日上午作出最後發佈，表示風暴正登陸雷州半島。

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

Link to relevant HKO weather report bulletins: 4/10 ● 5/10 ● 6/10 ● 7/10 ● 8/10 ● 9/10
香港天文台相關天氣報告連結： 4/10 ● 5/10 ● 6/10 ● 7/10 ● 8/10 ● 9/10

Due to the dominance of the subtropical ridge, it was very hot in Hong Kong in late September and early October. This was exacerbated by the subsidence associated with KOINU as the storm approached Taiwan on October 4. The maximum temperature recorded at the HKO was 34.6 degrees, the highest in October. As early as October 3, the HKO had already indicated that KOINU would come to within 800 km of Hong Kong in the afternoon of October 4, and that the #1 Standby Signal would be issued that night.

KOINU was about 790 km east of Hong Kong when the #1 Signal was issued at 9:40 pm on October 4. As KOINU was still quite far away from Hong Kong, the weather remained very hot on October 5 with light winds. By early morning on October 6, KOINU had moved to around 400 km from the territory. The HKO mentioned that the #3 Strong Wind Signal would be considered between 5 pm and 8 pm that day, and that winds in the territory were expected to strengthen. The exact timing of the signal change, 5:40 pm, was indicated in the tropical cyclone warning bulletin issued at 9:45 am. The HKO also revised its prediction on local winds in the 9-day weather forecast issued at 11:30 am that day. Winds were expected to reach force 6 to 7 generally later that day and on October 8/9, reaching force 8 occasionally in offshore waters and on high ground.

KOINU intensified and moved west-southwest on October 6. As the storm was moving rather slowly and was very compact, it was only around 250 km east-southeast of the territory when the #3 Strong Wind Signal was issued. While southern parts of Hong Kong could experience gale force winds on Sunday October 8, there were many variables that the HKO had to consider in deciding whether higher signals would be necessary, including KOINU's intensity, movement, and how far away its associated gales were from the territory. The Government Flying Service sent an aircraft to KOINU's vicinity twice on October 6 to gather meteorological measurements. Possibly as a result of the measurements, the HKO reduced KOINU's estimated gale force wind radius from 90-120 NM (167-222 km) at 8 pm to 60 NM (111 km) at 11 pm. Because of KOINU's southward movement that day, this would effectively mean that gales would not reach Hong Kong if KOINU were to continue its westward journey as predicted at that time. However, it was notable that some numerical models had started to hint at the possibility for KOINU to gain a bit of latitude before eventually turning southwest, which turned out to be the actual outcome.

The HKO upgraded KOINU into a severe typhoon at 2 am October 7. As the storm drew closer and the northeast monsoon strengthened, sustained strong force northerly winds began to be recorded in some offshore and elevated locations such as Waglan Island, Sha Chau and Tate's Cairn. There were also some showers during the day. The monsoon brought a drier, more stable air mass to southern China. Most of KOINU's outer rainbands dissipated as they were about to reach Hong Kong. Although KOINU started to move west-northwest in the afternoon, its circulation reduced in size and its eye became less well-defined on radar images. The HKO downgraded KOINU back into a typhoon at 9 pm, but soon adjusted its forecast track northwards, so that the storm was expected to come to within 100 km of the HKO a day later. It also stated that, while the #3 Signal would remain in force at least until noon October 8, it would consider whether or not to issue higher signals in the afternoon.

In the tropical cyclone warning bulletin issued for 5 am October 8, the HKO indicated that the #8 Gale or Storm Signal would be issued between noon and 2 pm that day. The time of the signal change was fixed at 12:40 pm in the 8 am bulletin, and the Pre-No. 8 Special Announcement was issued at 10:40 am. By that time, gale to storm force winds were recorded at Tate's Cairn and Waglan Island, while strong force winds were observed more generally at offshore and elevated locations such as Cheung Chau, Green Island, Tai Mei Tuk and Ngong Ping. North Point, a location within the Victoria Harbour, saw wind speeds hovering around the strong force threshold in the late morning to early afternoon.

With the pending signal change, the Education Bureau announced the suspension of classes for the day. Cargo handling services had been suspended earlier at 7 am October 8. Local ferry and high-speed hydrofoil services between Hong Kong and Macau were gradually suspended around noon and in the early afternoon, and bus services followed suit in the afternoon. By the time the #8 Northeast Gale or Storm Signal was issued at 12:40 pm, KOINU had moved to only 90 km south-southeast of the HKO, and was forecast to move west to west-northwest edging closer to the Pearl River Estuary. The prediction at that time had KOINU passing south of the Observatory later that night at a distance of around 70 km. With the possibility of KOINU's associated hurricane force winds reaching the seas south of Hong Kong, the HKO said it would assess the need for even higher signals.

As KOINU's circulation covered Hong Kong, rain became more persistent in the afternoon. Winds did strengthen somewhat but did not generally reach gale force level. For a few hours in the afternoon, KOINU took a turn to the north-northwest in the direction of the Pearl River Estuary. This brought KOINU's eyewall, which was stronger in its northern side, much closer to the seas immediately adjacent to the territory. At 6:45 pm, the HKO said hurricane force winds were registered at Huangmaozhou (an island around 55-60 km away to the south-southwest), and that the #9 Increasing Gale or Storm Signal would be issued at 7 pm. This marked the second time the #9 Signal was issued in a year - which last happened in 1999.

When the #9 Signal was issued, the MTR immediately suspended services over open sections of the railway system. Many people, including those who just got off work and those who were still spending the day out despite the #8 Signal, became stranded and had no means to return home except by taking taxis, some of which demanded surcharges of more than $500 or even $1,000. As the operations at the Hong Kong International Airport remained largely unaffected, most passengers arriving at Hong Kong during those few hours were unable to leave as the Airport Express service was suspended. This led to a debate over whether some form of public transport should remain accessible shortly after the issuance of the #9 Signal, or whether the HKO could provide advance warning for an upgrade to the #9 Signal, or more fundamentally, whether people not engaging in emergency or essential services should still be travelling around hours after the issuance of the #8 Signal.

Over the next few hours, HKO repeatedly mentioned that the need for the #10 Hurricane Signal would be assessed based on the changes in local wind conditions. KOINU skirted the seas around 70 km south of the HKO, and local winds turned east gradually. The Amber Rainstorm Warning was issued at 8:25 pm. From Chinese authorities, the wind speed at Miaowan Island reached 45.7 m/s (2-minute standard, 165 km/h) shortly before 10 pm. Its maximum 10-minute sustained wind speed was 39.9 m/s (144 km/h). Miaowan was about 20 km north of KOINU's centre at that time, and was affected by its most intense convective area within the eyewall.

Winds in Hong Kong were generally the strongest during the night of October 8. However, only a few were able to register gale force winds or above during KOINU's approach. The storm turned west again near 7 pm, and it was apparent that its eyewall would not touch the territory a few hours later. The HKO thus issued the #8 Northeast Gale or Storm Signal again at 11:50 pm, replacing the #9 Signal. Stranded passengers at MTR stations and the airport were able to make their way home as the MTR resumed its operations over open sections, and extended the Airport Express service to 3 am October 9.

While KOINU's structure deteriorated in the small hours of October 9, its rainbands continued to affect Hong Kong. Persistent heavy rain led to the upgrade of the Rainstorm Warning to Red at 1:55 am and further to Black at 4 am, which marked the first time that the Black Rainstorm Warning and the #8 Signal were in force concurrently. The Landslip Warning was issued at 2 am, and the Special Announcement on Flooding in the Northern New Territories was issued at 3:15 am. Winds moderated gradually as KOINU moved away, but the HKO had already indicated that the #8 Signal would remain in force at least until 11 am when the #9 Signal was replaced. At 5:45 am, the HKO stated that the #3 Strong Wind Signal would be issued at 11:40 am, replacing the #8 Signal. By early morning, gale force winds were only recorded at Waglan Island, and strong force winds were restricted to offshore locations and on high ground.

The Red Rainstorm Warning was issued at 10:30 am October 9, replacing the Black Warning. It was subsequently replaced by the Amber Warning at 2:30 pm, and the Amber Warning was cancelled at 5:45 pm. As for tropical cyclone warning signals, the #3 Strong Wind Signal was issued when KOINU was about 160 km west-southwest of Hong Kong. Except for a few stations, winds in Hong Kong moderated to below strong force level before noon. The #1 Standby Signal was issued at 2:40 pm, and was cancelled at 4:20 pm. KOINU was about 210 km west-southwest of Hong Kong by the time the #1 Signal was cancelled.

The Special Announcement on Flooding in the Northern New Territories and the Landslip Warning were cancelled at 4:15 pm October 9 and 6:30 am October 10, respectively. Within the first half of October 9, the HKO recorded 333.9 mm of rain. The daily rainfall of 369.7 mm broke the October record of 329.7 mm, set only two years ago during the influence of tropical cyclone LIONROCK. After KOINU's departure, the local weather improved gradually over the next few days. As the northeast monsoon became dominant in southern China, the temperatures were significantly lower than the week before; autumn had finally made its way to the region.

During KOINU's approach, the government received 44 reports of fallen trees, two landslip and seven flooding reports. 29 people sustained injuries and received treatment at the Accident and Emergency Department of public hospitals. It is noted that, unlike Hong Kong, the #8 Signal was the highest issued at Macau when KOINU came close, and the enclave was generally not affected by sustained gale force winds.

受副熱帶高壓脊支配，香港於 9 月底至 10 月初天氣酷熱。小犬於 10 月 4 日逐漸靠近台灣，其相關下沉氣流令酷熱天氣加劇，當天天文台錄得最高氣溫 34.6 度，創下 10 月新高。天文台早於 3 日已表示小犬將於 4 日下午進入 800 公里範圍，並將於當晚發出一號戒備信號。

一號信號於 10 月 4 日下午 9 時 40 分發出，當時小犬位於香港以東約 790 公里。由於小犬仍與香港有一段距離，5 日天氣仍然酷熱及吹微風。至 6 日早上，小犬移至本港約 400 公里外。天文台表示將於當日下午 5 至 8 時考慮改發三號強風信號，並預料本港風勢會增強。在上午 9 時 45 分的熱帶氣旋警報中，天文台將改發信號的時間定為下午 5 時 40 分。上午 11 時 30 分，天文台更新九天天氣預報，預測當天稍後及 10 月 8 至 9 日風力普遍達 6 至 7 級，離岸及高地間中 8 級。

小犬於 10 月 6 日增強並向西南偏西移動。由於風暴移速較低，加上結構緊密，三號信號發出時小犬於香港東南偏東方，距離只有約 250 公里。雖然香港南部或於周日 (10 月 8 日) 吹烈風，但天文台需考慮多個因素如小犬的強度、移動趨勢及其相關烈風區與本港的距離，從而決定是否需要改發更高信號。政府飛行服務隊於 6 日曾兩度派飛機靠近小犬，以收集氣象數據。或許是基於所獲取的數據，天文台將小犬的估計烈風區半徑由下午 8 時的 90 至 120 海里 (167 至 222 公里) 下調至下午 11 時的 60 海里 (111 公里)。由於小犬當天曾經南移，這表示如風暴按預測路徑向偏西移動，其烈風區將不會到達香港。但是，當時有數值模式預報開始指出，小犬有機會略為北移，其後再轉向西南移動，而此預測最終成真。

天文台於 10 月 7 日上午 2 時將小犬升格為強颱風。隨著風暴靠近及東北季候風增強，部分離岸及高地如橫瀾島、沙洲及大老山開始錄得持續強北風，而當日亦有驟雨。季候風為華南帶來較乾燥穩定的氣團，導致小犬外圍雨帶絕大部分於接近香港時消散。雖然小犬於下午開始向西北偏西移動，但其環流有所縮小，雷達圖上見到其風眼沒有之前般清晰。天文台於下午 9 時再次將小犬降格為颱風，但之後將其預測路徑北調，並預料風暴一天後會處於天文台 100 公里範圍內。天文台亦表示，雖然三號信號將至少維持至 8 日中午 12 時，但會考慮是否於下午改發更高信號。

在 10 月 8 日上午 5 時的熱帶氣旋警報中，天文台表示將於中午 12 時至下午 2 時改發八號烈風或暴風信號，並於上午 8 時的警報中將改發時間定於下午 12 時 40 分。預警八號熱帶氣旋警告信號之特別報告於上午 10 時 40 分發出，此時大老山及橫瀾島吹烈風至暴風，而其餘離岸及高地站如長洲、青洲、大美督及昂坪等普遍吹強風。位於維港內的北角，其風速於上午後段至下午初段維持於強風下限左右。

由於即將改發八號信號，教育局宣佈當日所有學校停課。貨櫃交收服務已於 10 月 8 日上午 7 時停止；本地渡輪及來往香港及澳門的水翼船服務大致於中午前後及下午初段陸續暫停，而巴士服務亦於下午跟隨。八號東北烈風或暴風信號於下午 12 時 40 分發出之時，小犬處於本港東南偏南方，距離天文台只有 90 公里，預料會向西至西北偏西移動並靠近珠江口。按照當時的路徑預測，小犬會於當晚在距離天文台約 70 公里的地方掠過。由於小犬的颶風區可能到達香港南面海域，天文台提及會評估是否需要改發更高信號。

隨著小犬的環流覆蓋香港，下午雨勢轉趨頻密；風勢雖然有所增強，但普遍未及烈風程度。當天下午，小犬曾向西北偏北移動達數小時之久，風暴劍指珠江口一帶。這令小犬較強的北部眼牆更為接近香港鄰近海域。下午 6 時 45 分，天文台表示黃茅州 (位於天文台西南偏南約 55 至 60 公里的小島) 錄得颶風，將於下午 7 時改發九號烈風或暴風風力增強信號。這是自 1999 年以來首次於一年內兩度發出該信號。

九號信號發出後，港鐵隨即暫停系統內露天路段的服務，不少剛下班或八號信號生效時仍然在外的市民因此未能回家。而選擇乘坐的士的人，部分需額外繳付超過 500 甚至 1000 元的車費。由於香港國際機場航班升降大致未受影響，大多數於九號信號生效時抵港的旅客因機場快線暫停運作而無法離開。此事其後引發社會各界對九號信號發出後初期應否維持部分公共交通服務、天文台能否在九號信號發出前給予更長預警、甚或從事非緊急或必須提供服務行業的人士於八號信號發出多個小時後仍然在街上逗留的討論。

此後數小時，天文台重複提及將視乎香港風力變化，評估是否需要發出十號颶風信號。小犬於天文台以南約 70 公里的海域掠過 (事後的熱帶氣旋報告更將其此時的強度上調為強颱風)，本地風向漸轉偏東，而黃色暴雨警告於下午 8 時 25 分發出。中國機構數據顯示廟灣島於下午 10 時前錄得最高 2 分鐘平均風速為每秒 45.7 米 (每小時 165 公里)，而最高 10 分鐘平均風速則為每秒 39.9 米 (每小時 144 公里)。廟灣當時位於小犬中心以北約 20 公里，正受眼牆中最猛烈的對流區吹襲。

香港風勢普遍於 10 月 8 日晚間達到頂峰，但只有數站於小犬靠近時錄得烈風或更高風速。風暴於下午 7 時後再度西轉，數小時後明顯看到其眼牆不會觸及本港。天文台於下午 11 時 50 分改發八號東北烈風或暴風信號，取代九號信號。隨著港鐵恢復露天路段服務，而且將機場快線的服務延長至 9 日凌晨 3 時，滯留於港鐵站及機場的乘客終能回家。

雖然小犬的結構於 10 月 9 日凌晨轉差，但其雨帶繼續影響本港。持續大雨令天文台分別於上午 1 時 55 分及 4 時改發紅色及黑色暴雨警告，這是首次黑色暴雨警告及八號信號同時生效。山泥傾瀉警告於上午 2 時發出，而新界北部水浸特別報告則於上午 3 時 15 分發出。隨著小犬移離，本港風勢逐漸緩和，但天文台早於九號信號被取代時已說明八號信號將至少維持至上午 11 時。至上午 5 時 45 分，天文台表示三號強風信號將於上午 11 時 40 分發出，取代八號信號。早上時份只餘橫瀾島仍吹烈風，而強風則局限於離岸及高地。

黑色暴雨警告於 10 月 9 日上午 10 時 30 分被紅色警告取代，其後於下午 2 時 30 分降為黃色，並於下午 5 時 45 分取消。熱帶氣旋警告方面，小犬於三號信號發出時位於香港西南偏西約 160 公里。除少數站點外，香港風勢於中午前已減弱至強風程度以下。一號戒備信號於下午 2 時 40 分發出，繼而於下午 4 時 20 分取消，當時小犬位於香港西南偏西約 210 公里。

新界北部水浸特別報告及山泥傾瀉警告分別於 10 月 9 日下午 4 時 15 分及 10 日上午 6 時 30 分取消。天文台於 9 日上半日錄得 333.9 毫米雨量，而全日的 369.7 毫米雨量打破 10 月 329.7 毫米的紀錄，該紀錄於兩年前熱帶氣旋獅子山影響本港時才創下。小犬離去後，本港天氣於其後數天逐漸改善。隨著東北季候風開始支配華南，氣溫明顯較前一星期為低，該區終於進入秋天。

小犬襲港期間，政府共接獲 44 宗塌樹、2 宗山泥傾瀉及 7 宗水浸報告。29 人在風暴期間受傷並前往公立醫院急症室接受治療。值得一提的是，與香港不同，澳門於小犬來襲時只發出八號信號，而當地普遍未受持續烈風影響。

Image Gallery 圖片庫

Figure 1 - Satellite image of KOINU in its initial stages of formation
圖 1 - 小犬形成初期之衛星雲圖

Figure 2 - Numerical model forecasts at 8 am September 29 (left) and October 2 (right)
圖 2 - 9 月 29 日 (左) 及 10 月 2 日 (右) 上午 8 時之數值模式預報

Figure 3 - Forecast tracks from various official agencies on September 30 (left) and October 5 (right)
圖 3 - 9 月 30 日 (左) 及 10 月 5 日 (右) 各官方氣象台之預測路徑圖

Figure 4 - Steering flow chart at 8 am October 2
圖 4 - 10 月 2 日上午 8 時之駛流場分佈圖

Figure 5 - Radar image (left) and satellite image (right) of KOINU when the island of Lanyu observed record-breaking gusts
圖 5 - 蘭嶼島錄得破紀錄陣風時之雷達圖 (左) 及衛星雲圖 (右)

Figure 6 - Satellite image showing KOINU reintensifying in northern South China Sea
圖 6 - 衛星雲圖顯示小犬於南海北部重新增強

Figure 7 - ECMWF (left) and GFS (right) model forecasts on October 7 showing KOINU might move west-northwest, bringing it closer to the Pearl River Estuary
圖 7 - ECMWF (左) 及 GFS (右) 模式於 10 月 7 日之預測顯示小犬或向西北偏西移動，進一步靠近珠江口

Figure 8 - Steering flow chart (top) and 500-hPa upper-level weather map (bottom) at 8 am October 7
圖 8 - 10 月 7 日上午 8 時之駛流場分佈圖 (上) 及 500 百帕高空天氣圖 (下)

Figure 9 - HKO's forecast track and intensity in the night of October 7, showing KOINU could come to within 100 km of the HKO on October 8
圖 9 - 10 月 7 日晚間香港天文台之預測路徑及強度，顯示小犬有機會於 10 月 8 日進入天文台 100 公里範圍內

Figure 10 - KOINU's estimated wind field at 2 pm October 8
圖 10 - 10 月 8 日下午 2 時之估計風場圖

Figure 11 - Wind field analysis at 9:18 pm October 8
圖 11 - 10 月 8 日下午 9 時 18 分之風場掃描圖

Figure 12 - Radar images (256-km range) at 6-hour intervals from 4 am October 8 to 10 am October 9
圖 12 - 10 月 8 日上午 4 時至 9 日上午 10 時每六小時之 256 公里範圍雷達圖

Figure 13 - Radar image (128-km range) at 9:48 pm October 8, about the time when Miaowan Island south of Hong Kong recorded the strongest winds during KOINU's approach
圖 13 - 10 月 8 日下午 9 時 48 分之 128 公里範圍雷達圖，當時位於香港以南之廟灣島錄得小犬來襲期間之最高風速

Figure 14 - Local weather element distribution maps at 3-hour intervals from 3 pm October 8 to 6 am October 9 (strong winds or above are represented by red wind barbs)
圖 14 - 10 月 8 日下午 3 時至 9 日上午 6 時每 3 小時之本港天氣元素分布圖 (強風或以上風速以紅色風矢標示)

Figure 15 - Wind speed time series at Cheung Chau, Green Island, North Point, Tai Mei Tuk, Tate's Cairn and Waglan Island (top to bottom) between October 8 and 9
圖 15 - 長洲、青洲、北角、大美督、大老山及橫瀾島 (上至下) 於 10 月 8 至 9 日之風速時間序列圖

Figure 16 - Past 24-hour rainfall distribution map ending at 3 pm October 9
圖 16 - 10 月 9 日下午 3 時之 24 小時雨量分佈圖

Figure 17 - KOINU's track near Hong Kong as reported in HKO's hourly tropical cyclone bulletins
圖 17 - 小犬於香港附近時之路徑，資料來自天文台的每小時熱帶氣旋警報

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。

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

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)

Table 3: Rainfall (in millimetres) contributed by KOINU 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)

Last Accessed 最近訪問日期: Sat Mar 22 2025 13:47:33 HKT
Last Modified 最近修訂日期: Thu May 09 2024