Typhoon Thelma trajectory analysis
Track Movement and Recurvature Characteristics
Typhoon Thelma (197704) 的生命史始 at Northwest Pacific远洋海域, 整体路径呈现典型的“NW行-N折”形态. formed初期 (7月19日至21日) , 系统自141°E附近 toward W, 纬度缓慢N抬至15.3°N, 经度显著W移, 显示其主要受副热带高压S侧引导气流控制. 7月22日后, Moving direction逐渐转为WNW, 并在接近120°E经线时出现明显的路径转折.
值得注意的是, 该Typhoon 在7月25日14:00至7月26日02:00期间, 纬度从24.3°N迅速跃升至26.6°N, 同时经度由120.3°EW移至118.5°E, 表明系统在Taiwan海峡以E海域完成了从NW toward toward N的转 toward 过程. 随后路径趋 at 正N, 最终 at 7月27日在30.6°N, 117.2°E附近减弱消散. 全程无Landfall记录, 主要在海上活动.
Intensity evolution and historical comparison
In terms of intensity, Thelma rapidly intensified to its peak before quickly weakening. It remained a tropical depression from July 19 to 21, with pressure above 1000hPa. On July 22, it intensified into a severe tropical storm and then deepened sharply within 24 hours: at 02:00 on July 23, pressure fell to 968hPa, and just 12 hours later, at 14:00 on July 23, it reached peak intensity with a minimum central pressure of 945hPa and maximum winds of 45m/s, making it a severe typhoon.
After its peak, the storm's intensity declined relatively quickly. From July 24, wind speeds fell to 40m/s and pressure rose to 960hPa, remaining near that level for about 24 hours. The storm began weakening significantly on the afternoon of July 25 as pressure rose to 975hPa. By the early hours of July 26, it had been downgraded to a tropical depression, with winds of 9m/s and pressure of 996hPa. Its intensity remained unchanged thereafter until it dissipated.
Compared with storms of the same name in the historical record, Thelma's 1977 intensity was between those of earlier storms with the same name. Its peak pressure of 945hPa was much lower than the 988hPa recorded in 1991, 990hPa in 1983, and 978hPa in 1980, but weaker than the 911hPa super typhoon record set in 1987. This indicates that the 1977 Thelma was a moderately strong typhoon system with the typical structure of a severe typhoon, although it weakened relatively quickly late in its lifecycle.
Typhoon Thelma routes
| Time | Position | Intensity | Wind · Pressure | Move toward |
|---|
| 07-19 14:00 | 11°N
141°E | Tropical Depression | - m/s
1007 hPa | - |
| 07-20 02:00 | 12.5°N
137°E | Tropical Depression | 10 m/s
1006 hPa | WNW |
| 07-20 14:00 | 14.5°N
133.4°E | Tropical Depression | 12 m/s
1003 hPa | WNW |
| 07-21 02:00 | 15.3°N
131.4°E | Tropical Depression | 12 m/s
1003 hPa | W |
| 07-21 14:00 | 15.3°N
129.3°E | Tropical Depression | 15 m/s
1000 hPa | W |
| 07-22 02:00 | 15.7°N
127.6°E | Severe Tropical Storm | 25 m/s
990 hPa | WNW |
| 07-22 14:00 | 16.4°N
126.3°E | Severe Tropical Storm | 25 m/s
985 hPa | WNW |
| 07-23 02:00 | 17.1°N
124.6°E | Severe Tropical Storm | 30 m/s
968 hPa | WNW |
| 07-23 14:00 | 18.3°N
122.7°E | Severe Typhoon | 45 m/s
945 hPa | NW |
| 07-24 02:00 | 19.2°N
121.3°E | Typhoon | 40 m/s
960 hPa | WNW |
| 07-24 14:00 | 20.1°N
120.1°E | Typhoon | 40 m/s
960 hPa | NW |
| 07-25 02:00 | 21.3°N
119.8°E | Typhoon | 40 m/s
960 hPa | NNE |
| 07-25 14:00 | 24.3°N
120.3°E | Typhoon | 35 m/s
975 hPa | N |
| 07-26 02:00 | 26.6°N
118.5°E | Tropical Depression | 9 m/s
996 hPa | NW |
| 07-26 14:00 | 29.2°N
117.1°E | Tropical Depression | 9 m/s
996 hPa | NNW |
| 07-27 02:00 | 29.7°N
117.1°E | Tropical Depression | 9 m/s
996 hPa | N |
| 07-27 14:00 | 30.6°N
117.2°E | Tropical Depression | 9 m/s
996 hPa | N |
Sampled rows shown; all 33 track points are available on the interactive map or via the public API .
FAQ
Typhoon Thelma was the 1977 Typhoon.
Thelma's designation 197704 is the historical number retained by the CMA, meaning the fourth numbered typhoon of 1977, and its international name was THELMA. The unified international numbering system for the Northwest Pacific did not begin until 1981; before then, individual agencies maintained separate numbering systems. The numbers assigned by the JMA in Japan, the Joint Typhoon Warning Center in the United States, and China's meteorological authorities may differ for the same typhoon and cannot be compared directly.
Where does the track data for Typhoon Thelma come from?
Track data sources: China Meteorological Administration Tropical Cyclone Best Track Dataset (CMA-STI); wind speeds are 2-minute sustained wind speeds.
What is the most powerful Typhoon Thelma?
Typhoon Thelma peak intensity is Severe Typhoon, max wind 45m/s, minimum central pressure 945 hPa.
Is the Typhoon Thelma Landfall?
According to records, the Typhoon Thelma is not in our coastal Landfall.
Where can I view typhoon Thelma's live track map?
TyphoonSays (taifengshuo.com) provides typhoon Thelma's Track history map, multinational meteorological agency Forecast comparison, wind range with IntensityTrend, page address: https://taifengshuo.com/typhoon/197704.
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