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 201218W (JELAWAT 杰拉華) - Profile 檔案 |
(Issued on December 20, 2012)
(於 2012 年 12 月 20 日發出)
Brief profile of JELAWAT 杰拉華小檔案:
| JTWC number 聯合颱風警報中心 (JTWC) 號碼 | 18W |
| International number 國際編號 | 1217 |
| Period of existence 生存時期 (JTWC) | 2012/09/20 20 HKT - 2012/10/01 02 HKT |
| Lifetime 壽命 (JTWC) | 10.25 days 日 |
| Maximum 1-minute wind (JTWC) JTWC 一分鐘平均最高中心風速 | 140 knots 節 (Category 5 Super Typhoon 五級超級颱風) |
| Minimum pressure (JTWC) JTWC 最低氣壓 | 918 hPa 百帕 |
| Highest TC signal by HKO (if applicable) 香港天文台發出最高熱帶氣旋警告信號 |
N/A 不適用 |
| Closest point of approach by HKO (if applicable) 香港天文台所示之最接近距離 (如適用) |
N/A 不適用 |
| Time of closest approach by HKO (if applicable) 香港天文台所示之最接近時間 (如適用) |
N/A 不適用 |
| Lowest pressure recorded at HKO (if applicable) 香港天文台錄得的最低氣壓 (如適用) |
N/A 不適用 |
TC track from HKWW 本站的熱帶氣旋路徑圖:
| Past HKWW Bulletins on JELAWAT 本站有關杰拉華的發佈 |
Please click here for bulletins on JELAWAT. 請按這裡。
| Storm Summary 氣旋摘要 |
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)
JELAWAT is the second category 5 super typhoon in 2012, forming a few days after the extratropical transition of cyclone SANBA, which was another category 5 super typhoon.
An area of low pressure north of Yap picked up strength on September 20. The JTWC issued the tropical cyclone formation alert at 2 am, and upgraded it into tropical depression 18W 12 hours later. At that time, 18W was moving westwards steadily due to the subtropical ridge covering north of it, but was expected to decelerate soon due to the collapse of the ridge. Its structure improved gradually and the JMA upgraded 18W into a tropical storm at 2 am the next day, naming it JELAWAT. The name was contributed by Malaysia, meaning Sultan fish.
JELAWAT dipped southwards during September 21. It was also apparent that the ridge was being eroded by a mid-latitude trough and as a result it retreated, leaving a weakness north of JELAWAT. The storm was situated in a pressure col and was almost motionless on September 22. Numerical solutions showed much divergence as to what would happen next; a few models were consistently producing an abrupt turn to the north or north-northwest, while others believed that the ridge would rebuild and would drive the storm towards the Luzon Strait. In the meantime, JELAWAT gradually absorbed energy and intensified to a typhoon on September 23.
JELAWAT turned northwards in the morning of September 23 and started to deepen rapidly. The JTWC estimated that JELAWAT was carrying winds of 75 knots at 8 am; this estimate surged to 100 knots at 2 pm and further to 120 knots at 8 pm. Using 10-minute averages, the JMA also provided an estimate of 100 knots by the end of the day. The eye became much clearer on satellite images during the day, and the central dense overcast also grew in size. Different agencies also came to an agreement that the ridge would indeed extend, but not as much as to guide JELAWAT into the Luzon Strait.
The storm continued to move NNW on September 24. It appeared to weaken a bit in the morning due to eyewall replacement; its eye shrank in size and eyewall cloud top temperatures increased. However, this drop was temporary and the storm soon picked up strength again. The eye became cloud-free overnight and it intensified into a category 5 super typhoon (140 knots) at 2 am on September 25. The HKO was estimating JELAWAT's strength at 120 knots while JMA 110 knots. It was apparent that energy was ample in the region, given that SANBA achieved category 5 status within 1000 km of JELAWAT's position less than two weeks ago.
The 140-knot strength persisted for more than a day as JELAWAT moved steadily across the Philippine Sea. JELAWAT's eye shrank again and some clouds started to fill, but the storm maintained category 4 super typhoon strength on September 26 and 27. Due to the orientation of the ridge, JELAWAT's westward track component increased and edged closer to Taiwan. The CWB issued the Sea Warning at 2:30 am on September 27, anticipating force 7 wind radius to touch the 100 km sea area from the territory. JELAWAT crossed the ridge axis that night, and it started to recurve on September 28. The risk of the storm touching Taiwan was reduced and the Warning was lifted at 8:30 pm that night.
Ocean heat content dropped as JELAWAT moved to higher latitudes. The storm was at that time on a weakening trend but it still maintained appreciable strength. It also accelerated as it was caught by the westerlies. JELAWAT scored a direct hit on Okinawa early on September 29, just two weeks after SANBA swept across the city. The storm did not spend much time there as it continued to move northeast rapidly. Due to increasing wind shear, JELAWAT became increasingly asymmetrical and weakened into a category 1 typhoon.
JELAWAT made landfall near Hamamatsu in the afternoon of September 30, while moving northeast in excess of 50 km/h. It crossed eastern Japan and finally became extratropical on October 1.
杰拉華是 2012 年第二個五級超級颱風，它於本年首個五級風暴三巴轉化為溫帶氣旋後數天形成。
在雅蒲島以北的一個低壓區於 9 月 20 日逐漸增強，聯合颱風警報中心 (JTWC) 於凌晨 2 時對其發出熱帶氣旋形成警報，並於 12 小時後升格為熱帶低氣壓。當時 18W 受覆蓋其北面的副熱帶高壓脊影響而向西移動，但預料該脊將崩潰，令 18W 移速減慢。18W 的結構轉好，日本氣象廳 (JMA) 於翌日凌晨 2 時將其升格為熱帶風暴，命名為杰拉華。此名稱由馬來西亞提供，意思為蘇丹魚。
杰拉華於 21 日南移，而副熱帶高壓脊亦明顯開始被西風槽侵蝕，逐漸東退並令杰拉華以北出現一個弱點。杰拉華處於鞍場中，於 22 日幾乎停留不動。數值預報模式對之後的預測有頗大分歧，部分模式多佈預測杰拉華將突然轉北或西北偏北移動，而其他則預計副高將再度增強並使風暴移近呂宋海峽。與此同時，杰拉華逐漸吸收能量，並於 23 日增強為颱風。
杰拉華於 23 日早上轉向北移，並快速增強。JTWC 於上午 8 時估計杰拉華的中心風力達 75 節，到下午 2 時上調至 100 節，而至晚上 8 時更調高至 120 節。使用 10 分鐘平均風速的 JMA 亦於當晚估計杰拉華風力達 100 節。杰拉華的風眼於當天明顯變得清晰，中心密集雲區增大。各機構對其路徑亦有共識，預計副高會增強，但未能使杰拉華進入呂宋海峽。
風暴於 24 日繼續向西北偏北移動，它於早上因眼牆置換而稍微減弱，風眼收縮而眼牆雲頂溫度上升，但此減弱非常短暫，不久杰拉華再度增強。杰拉華的風眼清晰無雲，於 25 日凌晨 2 時增強成五級超級颱風 (140 節)。天文台估計杰拉華風力達 120 節，而 JMA 則為 110 節。三巴在少於兩周前才於杰拉華的位置 1000 公里範圍內增強成五級風暴，就此看來該區的能量非常充足。
杰拉華穩定於菲律賓以東海域移動，其五級強度維持了一天多。隨後杰拉華的風眼縮細且有雲帶填入，但風暴仍於 26 及 27 日維持四級超級颱風強度。受副高形狀影響，杰拉華路徑的西向量增加，更為靠近台灣。台灣中央氣象局於 27 日凌晨 2 時 30 分發出海上颱風警報，預計七級風圈將進入台灣 100 公里海域。杰拉華於當晚橫過副高脊線，並於 28 日開始轉向。由於侵襲台灣的機會減低，中央氣象局於當晚 8 時 30 分解除颱風警報。
隨著杰拉華移至較高緯度，海洋熱含量降低，它開始逐漸減弱，但仍維持可觀強度，而杰拉華亦開始受西風帶影響而加速。杰拉華於 29 日早上正面吹襲沖繩，該地於兩周前才經歷颱風三巴吹襲。杰拉華未有停留，繼續往東北快速移動。由於垂直風切變提高，杰拉華的結構開始變得不對稱，且減弱為一級颱風。
杰拉華在 30 日下午於濱松市一帶登陸，當時正以時速超過 50 公里向東北推進。它於當天橫過日本，最後於 10 月 1 日轉化為溫帶氣旋。
| Figures 圖片 |
Figures 1a and 1b - Steering flow charts at 8 am on September 21 and 24
圖 1a 及 1b - 9 月 21 及 24 日上午 8 時之駛流場圖
Figures 2a and 2b - Forecast tracks from various official agencies on September 22 and 25
圖 2a 及 2b - 9 月 22 及 25 日各官方氣象台預測路徑圖
Figure 3 - JELAWAT at peak intensity. The eye was essentially cloud-free
圖 3 - 杰拉華接近巔峰強度時的衛星圖片，風眼一帶幾乎無雲
Figure 4 - Wind field at 8:26 pm on September 24
圖 4 - 9 月 24 日下午 8 時 26 分之風場圖
Figure 5 - Radar image showing JELAWAT directly overhead Okinawa
圖 5 - 雷達圖顯示杰拉華正在沖繩上空
Figure 6 - JELAWAT about to make landfall in Japan while undergoing extratropical transition
圖 6 - 杰拉華即將登陸日本，並正進行溫帶氣旋轉化
| Other Data 其他數據 |
Table 1: Track data from HKWW:
表一 : 香港天氣觀測站之路徑資料
| YYMMDDZZ Lat Long Wind 12092006 138N1335E 025 12092012 137N1323E 030 12092018 135N1314E 035 12092100 131N1309E 045 12092106 128N1306E 045 12092112 125N1300E 050 12092118 122N1298E 055 12092200 119N1297E 055 12092206 117N1297E 055 12092212 118N1296E 055 12092218 119N1295E 060 12092300 119N1290E 075 12092306 121N1289E 100 12092312 127N1287E 120 12092318 131N1286E 130 12092400 136N1285E 130 12092406 142N1282E 130 12092412 146N1281E 135 12092418 152N1278E 140 12092500 157N1278E 140 12092506 164N1275E 140 12092512 169N1271E 140 12092518 172N1267E 140 12092600 175N1265E 135 12092606 180N1261E 135 12092612 184N1259E 130 12092618 191N1253E 130 12092700 196N1248E 130 12092706 202N1244E 130 12092712 209N1240E 130 12092718 217N1237E 125 12092800 225N1240E 120 12092806 234N1244E 115 12092812 242N1252E 110 12092818 251N1260E 105 12092900 260N1273E 100 12092906 270N1285E 100 12092912 279N1303E 100 12092918 294N1322E 095 12093000 317N1342E 085 12093006 335N1358E 075 12093012 357N1383E 070 12093018 391N1410E 060 12100100 417N1443E 055 |
Table 2: Track data from JTWC:
表二 : 聯合颱風警報中心之路徑資料
ID Name YYMMDD ZZZZ Lat Long Basin Wind Pres 18W JELAWAT 121001 0000 41.0N 144.8E WPAC 40 993 |
Last Accessed 最近訪問日期: Fri Apr 26 2024 01:43:30 HKT
Last Modified 最近修訂日期: Mon Jul 24 2023
