DOLPHIN strengthened into a category 2 typhoon early today but weakened back into category 1 tonight. At 20 HKT, DOLPHIN was centred about 1370 km (740 NM) SW of Iwo Jima.
DOLPHIN is expected to recurve after it traverses the ridge axis.
白海豚將沿副熱帶高壓脊西轉西北面向北轉東北移動。
Intensity Analysis 強度分析
Current T-number: T4.0/4.5/W0.5/24 HRS
DOLPHIN is entering regions with high shear and cooler temperatures. Weakening is expected all the way until dissipation between t+48 and t+72.
DOLPHIN should decelerate and move N to NNW along the western periphery of the subtropical ridge. A recurvature is expected in the extended taus.
白海豚將沿副熱帶高壓脊西面向北或西北偏北移動，移速將會減慢。
Intensity Analysis 強度分析
Current T-number: T4.5/4.5/D1.0/24 HRS
DOLPHIN intensified under good outflow from the arriving trough. Intensification is possible for another day, after which shear will increase significantly and DOLPHIN will gradually weaken by then.
現時的 T 號碼: T4.5/4.5/D1.0/24 HRS 受惠於西風槽前的良好輻散，白海豚於過去 12 小時大幅增強。預料增強的趨勢將可維持至明天，隨後將受到頗高垂直風切變的影響而逐漸減弱。
Effects on Hong Kong 對香港的影響
No threat to Hong Kong is expected within the next 72 hours.
白海豚於未來的 72 小時將不會對香港構成任何影響。
Next Update 下次更新
23 HKT, 2008/12/16 (or earlier 或更早)
Probabilities of TC Signals from HKO 香港天文台(已)發出熱帶氣旋警告信號的機率
DOLPHIN maintained its strength in the past 24 hours, and has continued to move west at about 20 km/h. At 20 HKT, DOLPHIN was centred about 910 km (490 NM) WNW of Yap.
The trough that is responsible for the breakdown of the ridge is now north of the weakness. DOLPHIN is expected to turn to a poleward track in the next 48 hours.
造成副高弱點的西風槽現正在該弱點北方。預料白海豚將於未來 48 小時逐漸減慢並轉向偏北方向移動。
Intensity Analysis 強度分析
Current T-number: T3.5/3.5/S0.0/24 HRS
Improved divergence associated with the trough may bring some intensification in the next 24 to 48 hours.
現時的 T 號碼: T3.5/3.5/S0.0/24 HRS 槽前較佳的輻散有望令白海豚於未來 24 至 48 小時增強；轉向後白海豚將在較高垂直風切變和較低海溫的環境下減弱。
Effects on Hong Kong 對香港的影響
No threat to Hong Kong is expected within the next 72 hours.
白海豚於未來的 72 小時將不會對香港構成任何影響。
Next Update 下次更新
23 HKT, 2008/12/15 (or earlier 或更早)
Probabilities of TC Signals from HKO 香港天文台(已)發出熱帶氣旋警告信號的機率
The ridge north of DOLPHIN has broken and a weakness is clearly seen. As DOLPHIN continues to strengthen, there is now an increased possibility for it to recurve. Nevertheless, there is still a slight chance for the ridge to recover before that happens and this could lead to a more westward track.
Current T-number: T3.5/3.5/D0.5/24 HRS
Shear has strengthened very slightly in the past 24 hours. Some intensification is still expected before its recurvature near t+48.
27W intensified into a tropical storm this afternoon and was named DOLPHIN. It has also decelerated appreciably in the past 24 hours. At 20 HKT, DOLPHIN was centred about 600 km (330 NM) W of Guam.
DOLPHIN is now entering a weak steering environment as the eastern ridge collapsed rapidly. Quite a number of numerical models now call for a recurvature due to an arriving mid-latitude trough that will widen the weakness sufficiently. However at this moment it is still far from certain whether this will happen, and the alternative scenario that the extension of the subtropical ridge will recover the weakness soon after the trough passes cannot be ruled out. Either case, DOLPHIN's forward speed is reduced compared with previous forecasts.
Current T-number: T3.0/3.0/D1.0/24 HRS
Intensity forecast also changes significantly from yesterday's bulletin. The adverse effect brought by the inability to organize is reduced as DOLPHIN slowed down dramatically. As shear is still light, some intensification is expected before t+48.
現時的 T 號碼: T3.0/3.0/D1.0/24 HRS 強度預測亦有大幅度的修改。由於白海豚移速比預期慢，它將有較多時間在洋面上整固。因垂直風切變仍在較弱水平，預料 白海豚可於未來 48 小時內稍為增強。
Effects on Hong Kong 對香港的影響
No threat to Hong Kong is expected within the next 72 hours.
白海豚於未來的 72 小時將不會對香港構成任何影響。
Next Update 下次更新
23 HKT, 2008/12/13 (or earlier 或更早)
Probabilities of TC Signals from HKO 香港天文台(已)發出熱帶氣旋警告信號的機率
There is a slight weakness between two subtropical ridges at 135E. Thus 27W is expected to track WNW towards the weakness in the next 36 hours, but afterwards it will be affected by the western ridge and move WSW towards Philippines.
Current T-number: T2.0/2.0/D0.5/24 HRS
A patch of dry air is ahead of 27W. Together with constant easterly flow that disrupts divergence, 27W is now expected to intensify slightly only, attaining marginal tropical storm status.
現時的 T 號碼: T2.0/2.0/D0.5/24 HRS 27W 前面有大範圍的乾空氣。加上該區中高層吹強勁東風，輻散仍在較差水平。預料 27W 將只可稍微增強至熱帶風暴下限強度。
Effects on Hong Kong 對香港的影響
No threat to Hong Kong is expected within the next 72 hours.
27W 於未來的 72 小時將不會對香港構成任何影響。
Next Update 下次更新
23 HKT, 2008/12/12 (or earlier 或更早)
Probabilities of TC Signals from HKO 香港天文台(已)發出熱帶氣旋警告信號的機率
A temperate cyclone moved southwest in the past two days and acquired tropical characteristics, and has strengthened into a tropical depression (temporary number 27W by the JTWC). At 20 HKT, 27W was centred about 660 km (360 NM) ESE of Guam.
A broad subtropical ridge is situated to the north of 27W. Under its influence it is expected that 27W will move WNW then W in the next 72 hours. The high pressure area currently near 20N 130E should drive 27W WSW later in the forecast period.
Current T-number: T1.5/1.5/INT OBS
Slow organization is expected within the next 72 hours as 27W moves into an area of progressively warmer waters with light to moderate shear.
現時的 T 號碼: T1.5/1.5/INT OBS 隨著 27W 移向較高水溫的海域和微弱至中等垂直風切變的環境，預料該系統可於未來 72 小時逐漸發展。
Effects on Hong Kong 對香港的影響
No threat to Hong Kong is expected within the next 72 hours.
27W 於未來的 72 小時將不會對香港構成任何影響。
Next Update 下次更新
23 HKT, 2008/12/11 (or earlier 或更早)
Probabilities of TC Signals from HKO 香港天文台(已)發出熱帶氣旋警告信號的機率
Active Tropical Cyclone(s) 正活躍之熱帶氣旋
