CHANTHU intensified into a severe tropical storm as it skirts past the eastern coast of Japan, and has started extratropical transition. At 2 pm, CHANTHU was centred about 280 km (150 NM) SSE of Sapporo.
CHANTHU is the 99th name in the tropical cyclone name list. It was contributed by Cambodia, and is the name of a type of flower. This name was used in 2004 and 2010, with the latter occurrence necessitating the #3 Strong Wind Signal in Hong Kong.
CHANTHU is expected to move NNE along the western periphery of the subtropical ridge in the next 12 hours.
燦都將於未來 12 小時沿副熱帶高壓脊西部向東北偏北移動。
Intensity
Analysis 強度分析
Current T-number 現時的 T 號碼: T3.0/3.0/D1.0/24 HRS
Contrary to our forecast, CHANTHU has gained strength over the past 24 hours. It has started extratropical transition and is expected to become fully extratropical by t+12, after crossing Hokkaido. Its intensity should remain more or less constant in the transition period.
CHANTHU is the 99th name in the tropical cyclone name list. It was contributed by Cambodia, and is the name of a type of flower. This name was used in 2004 and 2010, with the latter occurrence necessitating the #3 Strong Wind Signal in Hong Kong.
CHANTHU is expected to move N turning to NNE along the western periphery of the subtropical ridge within the next 36 hours, accelerating in the process.
燦都將於未來 36 小時沿副熱帶高壓脊西部向北轉東北偏北移動，並逐漸加速。
Intensity
Analysis 強度分析
Current T-number 現時的 T 號碼: T2.0/2.5/W0.5/24 HRS
CHANTHU is struggling against dry air intrusion and is conceding gradually; its convections are dissipating, especially in the southern semicircle. As CHANTHU moves north, lower sea temperatures will also work against the storm. CHANTHU is therefore not expected to intensify, although it will not weaken too much given the projected increase in its speed. Extratropical transition is expected by t+36.
CHANTHU has intensified into a severe tropical storm. At 2 pm, CHANTHU was centred about 460 km (250 NM) NE of Iwo Jima.
燦都已增強為強烈熱帶風暴。在下午 2 時，燦都集結在硫磺島東北約 460 公里 (250 海里)。
TC
Naming 氣旋命名
CHANTHU is the 99th name in the tropical cyclone name list. It was contributed by Cambodia, and is the name of a type of flower. This name was used in 2004 and 2010, with the latter occurrence necessitating the #3 Strong Wind Signal in Hong Kong.
CHANTHU is now steered by the subtropical ridge to its east. The storm is expected to move NNW turning to N as it crosses the ridge axis near t+36. Recent numerical model runs have further increased CHANTHU's speed at later taus, and the storm is now forecast to travel in excess of 50 km/h along the east coast of Japan after t+48.
Current T-number 現時的 T 號碼: T2.5/3.0/S0.0/24 HRS W0.5/12 HRS
CHANTHU intensified last night but convections have thinned recently. Nevertheless, sea temperatures and upper-level divergence are suitable for tropical cyclone development, and slight intensification is expected in the next 24 hours. Beyond that, sea temperatures will drop and the storm should weaken slightly, before transforming into an extratropical cyclone by t+72.
CHANTHU is the 99th name in the tropical cyclone name list. It was contributed by Cambodia, and is the name of a type of flower. This name was used in 2004 and 2010, with the latter occurrence necessitating the #3 Strong Wind Signal in Hong Kong.
CHANTHU is still moving NNE, but is expected to turn north soon as the subtropical ridge to the east assumes steering influence. The ridge will extend westwards, causing CHANTHU to move NNW briefly between t+24 and t+48. CHANTHU is expected to cross the ridge axis near t+72 and recurve gradually thereafter.
CHANTHU is under some vertical wind shear and most of its convections are displaced to the north. However, warm seas and decent upper-level divergence should be enough to fuel its development in the next 48 to 72 hours. The storm will weaken beyond t+72 due to cooler sea temperatures.
An equatorial ridge is positioned southeast of 09W, and should drive the system towards the northeast over the next 24 hours. Thereafter, the equatorial ridge is expected to weaken and, together with a westward extension of the subtropical ridge in the northeast, 09W should then move north and later turn to NNW.
More convections are spinning around 09W's centre and the system appears to be developing steadily. Sea temperatures in the region are quite warm (around 30 degrees) and upper-level divergence is decent. 09W should be able to intensify gradually over the next 72 hours.
Active Tropical Cyclone(s) 正活躍之熱帶氣旋
