According to CWB, SEPAT made its first landfall at Central Taiwan at 5:40 a.m. this morning. It traversed the mountainous area during the morning and re-emerged into the Taiwan Strait before noon today. In the meantime, SEPAT weakened from a category 4 typhoon into a category 2 typhoon. A double eyewall appeared briefly last night.

根據台灣中央氣象局，聖帕已於今晨5時40分於台灣中部登陸。聖帕橫越台灣山脈，並於中午前移至台灣海峽。同時，聖帕由昨晚的四級颱風減弱至出海後的二級颱風。昨晚聖帕曾短暫出現雙重眼壁結構。

Under the influence of the ridge east of SEPAT, the storm moved NW before reaching Taiwan, while due to interactions with the mountains in Taiwan SEPAT moved W to WNW while traversing the island. It is forecast that SEPAT will track NW to NNW in the remainder of the forecast period along a weakness between the continental high and the weakened subtropical ridge. SEPAT will soon make its second landfall at central Fujian.

受聖帕附近的東南氣流影響，聖帕於登陸台中前穩定地向西北方向移動。在橫越台灣山脈期間，聖帕受山勢影響而向西至西北偏西移動。預料聖帕會移向位於大陸高壓和副熱帶高壓脊之間的弱點，在餘下時間向西北至西北偏北移動。

As of 06 UTC, SEPAT's convection wraps 1.2 on the log10 spiral which gives a T-number of 4.5-5.0 or equivalently 77-90 knots wind (typhoon category 1-2). SEPAT will weaken rapidly in the next 24-48 hours into a low pressure area.

在 06 UTC，聖帕的T號碼為4.5 - 5.0，即 77-90 節的風速。聖帕將會在未來24-48小時急劇減弱至一低壓區。

The subsidence air ahead of SEPAT is expected to bring very hot and hazy weather to Hong Kong tomorrow, together with occasional thunderstorms (2007/08/19).

聖帕的外圍下沉氣流會在明天為本港帶來酷熱、有煙霞的天氣，伴以幾陣狂風雷暴。

23 HKT, 2007/08/19 (or earlier 或更早)

SEPAT has been moving NW steadily during the past 24 hours. The system has also weakened slightly since last night, where the eye becomes rugged (cloud-filled) and enlarged afterwards. It is now a category 4 typhoon.

聖帕於過去24小時向西北穩定移動。該系統亦從昨晚開始輕微減弱，風眼擴大且變得渾濁 (有雲)。聖帕現時為一四級颱風。

The ridge east of SEPAT developed significantly during the past 24 hours, leading to an accelerated motion towards the NW. Several eyewall replacement cycles have occurred during the same period that gave rise to the temporary erratic movement. Meanwhile, the subtropical ridge has further shifted north during the same period. The forecast philosophy for SEPAT remains almost the same, with the track of SEPAT being more WNW after making landfall at Taiwan due to the extending subtropical ridge now anchored at western Japan.

在聖帕附近的東南氣流於過去24小時顯著增強，使聖帕加速向西北方向移動。同時，聖帕於昨晚進行了幾次眼牆更替週期，因而帶來短暫的不規則移動。在聖帕北方的副熱帶高壓脊於昨晚稍稍北抬。對於聖帕的預測方向大致不變，由於副熱帶高壓脊將預計稍為向西伸展，聖帕將會在登陸台灣後採取較為西北偏西的方向移動。

As of 06 UTC, SEPAT has an off-white eye surrounded by gray shade of black (from satellite image) which gives a T-number of 6.0 or equivalently 115-120 knots wind (typhoon category 3-4). It is forecast that SEPAT will slightly weaken before making landfall at Taiwan due to restricted outflow, while it will weaken significantly while traversing Taiwan before finally taking its second landfall at Fujian.

Most parts of Taiwan will be under storm force winds or above tomorrow, due to the extreme intensity of SEPAT and that the storm wind circle is almost as large as the Island.

The subsiding air ahead of SEPAT is expected to bring very hot and hazy weather to Hong Kong tomorrow (2007/08/18).

19 HKT, 2007/08/18 (or earlier)

SEPAT made an abrupt turn to the NW at about 06 UTC yesterday. The system then moved steadily in the northwest direction in the past 24 hours, now reaching 18 degrees north. In the meantime, SEPAT further intensified into a category 5 super typhoon, with central wind speed of 140 knots given by the Joint Typhoon Warning Center.

The subtropical ridge north of SEPAT has further extended to the west in the past 24 hours, with the western margin situated at about 116E as of 06 UTC. However it is also evident from the steering flow chart that the ridge has shifted north a bit, thus having less influence on the track of SEPAT. The subtropical ridge has also reoriented into ESE-WNW direction. Meanwhile, the ridge east of SEPAT became the primary driving force that led the storm in a NW-NNW direction in the past 24 hours.

The subtropical ridge is forecast to extend to the west in the remaining forecast period. However, since its position is quite north, it is expected that its effect on SEPAT will only be observable later in the forecast period, which leads SEPAT into a more WNW direction. SEPAT should move northwest before making landfall at Taiwan.

As of 06 UTC, SEPAT has a warm medium gray eye surrounded by gray shade of white (from satellite image) which gives a T-number of 7.0 or equivalently 140 knots wind (typhoon category 5). It is expected that the poleward outflow channel will be hindered by the extension of the subtropical ridge north of SEPAT and the system should have reached peak intensity by now. It will weaken in the remainder of the forecast period due to lower sea surface temperatures and its proximity to the landmass of Taiwan.

No threat to Hong Kong is expected within 72 hours.

19 HKT, 2007/08/17 (or earlier)

During the past 24 hours, SEPAT moved west at a speed of about 6 knots, intensifying at greater than climatological rate at the same time. It is now a category 4 super typhoon, reaching 1-min sustained wind speed of 130 knots.

Compared with yesterday, the equatorial anticyclone located at the Philippines weakened appreciably, which means that the offset mechanism of the poleward component of the steering forces diminishes. SEPAT is now located at the southwest quadrant of the driving anticyclone anchored SE of Japan, and thus it is generally expected that SEPAT will gradually turn into a WNW to NW track in the next 48 hours. This is also supported by the expectation that the ridge will reorient in a NW-SE direction later in the forecast period.

Since the subtropical ridge north of SEPAT is expected to extend to the west during the forecast period, the poleward component of SEPAT's track will decrease at t+72, enabling SEPAT to switch to a WNW track.

As of 06 UTC, SEPAT has a 16 NM off-white eye surrounded by white shade which gives a T-number of 6.5 or equivalently 127 knots wind (typhoon category 4). With good outflow channels and favourable envionment, SEPAT was able to intensify at greater than climatological rate during the past 24 hours. It is expected that the poleward outflow channel will be hindered by the extension of the subtropical ridge north of SEPAT and the rate of intensification will substantially decrease. According to the latest forecast, SEPAT should reach peak intensity as a marginal category 5 super typhoon in the next 12-24 hours, after which its strength will decrease due to decreasing sea surface temperatures and interaction with the landmass of Taiwan.

No threat to Hong Kong is expected within 72 hours.

19 HKT, 2007/08/16 (or earlier)

During the past 24 hours, SEPAT moved west at a speed of about 8-9 knots, intensifying at a climatological rate at the same time. It is now a category 2 typhoon.

From the steering flow chart, it is evident that the subtropical ridge to the north of SEPAT is building up and strengthening rapidly. Together with the weak ridging near the Philippines, SEPAT should move westwards in the next 24 hours. It is predicted that the subtropical ridge will then build to the south and east of SEPAT gradually and therefore contributing poleward component to the system after t+24, enabling a WNW to NW track

As of 09 UTC, SEPAT's convection wraps 1.35 on the log10 spiral, which gives a T-number of 4.5-5.0 or equivalently 77-90 knots wind (typhoon category 1-2). With good outflow channels and favourable envionment, SEPAT was able to intensify at a climatological rate during the past 24 hours. It is projected that the vertical wind shear to the west of the system will gradually weaken, and the sea surface temperature will remain high (>28 degrees Celsius) which will allow SEPAT to intensify at a climatological rate through t+24. After that time, the ridging north of SEPAT will restrict poleward outflow and the rate of intensification will substantially decrease. SEPAT's intensity should peak at t+48-72, before making landfall at Taiwan.

No threat to Hong Kong is expected within 72 hours.

19 HKT, 2007/08/15 (or earlier)

Due to a lack of steering flow, SEPAT has been moving slowly in the past 24 hours, drifting towards the southwest. SEPAT is now at a position of low vertical wind shear and favourable sea surface temperature, which enabled the system to gain strength at a climatological rate during the past 24 hours.

From the steering flow chart, it is evident that the subtropical ridge to the north of SEPAT is building up and strengthening rapidly. Together with the weak ridging near the Philippines, SEPAT should move westwards in the next two days. The majority of the models have good agreement concerning SEPAT's movement in the first 48 hours, but their forecasts diverge afterwards. It is generally forecast that the dominant ridge (the ridge north of SEPAT) will extend westward, and since SEPAT will be positioned at the southwest quadrant of the ridge at that time, a WNW to NW track is predicted after t+48. However, whether or not the poleword component is large remains largely uncertain, with some models predicting a more northerly track that enables SEPAT to avoid landfall on Taiwan.

As of 12 UTC, SEPAT's convection wraps 1.00 on the log10 spiral, which gives a T-number of 3.5 or equivalently 55 knots wind (severe tropical storm). With good outflow channels and favourable envionment, SEPAT was able to intensify at a climatological rate during the past 24 hours. It is projected that the vertical wind shear to the west of the system will gradually weaken, and the sea surface temperature will remain high (>28 degrees Celsius) which will allow SEPAT to intensify at a climatological rate through t+96.

No threat to Hong Kong is expected within 72 hours.

22 HKT, 2007/08/14 (or earlier)