Tropical Depression SEPAT: Discussions, Analysis and Image

[WindRunner]

That AMSRE pass is beautiful, wxmann.

As for landfall intensity, I think that it could still be a SS Cat 4 when it hits, but it will (obviously) be a much larger storm by then. I could see 125kts when it hits, though I wouldn't be surprised if it was down to 110kts or so.

[HurricaneBill]

Last Category 3+ typhoon to landfall on Taiwan:
2005: (Super) Typhoon Haitang 105KT (1-min) (Category 3)
2005: Typhoon Longwang 105KT (1-min) (Category 3)

Last Category 4+ typhoon to landfall on Taiwan:
2000: (Super) Typhoon Bilis 140KT (1-min) (Category 5)

Some of Taiwan's worst typhoons:

1952: Typhoon Bess (153 killed)

1957: (Super) Typhoon Virginia (86 killed)

1958: (Super) Typhoon Winnie (Category 5 landfall) (43 killed)

1960: (Super) Typhoon Shirley (210 killed)

1961: (Super) Typhoon Pamela (293 killed) (>$4million damage)

1962: (Super) Typhoon Opal (Category 5 landfall) (107 killed)

1963: (Super) Typhoon Gloria (363 killed) (>$17.5million damage) (Taiwan's Central Weather Bureau had forcasted Gloria to curve to the north and miss Taiwan. Instead, Gloria continued a WNW movement right into northern Taiwan. 4 meteorologists were arrested and charged with dereliction of duty for failing to properly forecast Gloria's path. Widely viewed as political scapegoats, the meteorologists were eventually released.)

1965: (Super) Typhoon Dinah (100 killed)

1967: (Super) Typhoon Carla (101 killed)

1969: (Super) Typhoon Elsie (105 killed)

1973: (Super) Typhoon Nora (68 killed)

1977: Typhoon Thelma (72 killed)

1977: Typhoon Vera (44 killed)

1983: Typhoon Ellen (82 killed)

1986: Typhoon Wayne (52 killed) ($405million damage) (For over 2 weeks, Wayne's erratic path brought him over or near Taiwan 3 times.)

1987: (Super) Typhoon Lynn (61 killed)

1989: Typhoon Sarah (33 killed) ($39million damage)

1994: Typhoon Tim (43 killed) ($96.3million damage)

1994: (Super) Typhoon Doug (30 killed) ($232 million damage)

1996: Typhoon Gloria (20 killed) ($200 million damage)

1996: (Super) Typhoon Herb (75 killed) ($5 BILLION damage) (Taiwan's costliest typhoon)

2000: (Super) Typhoon Bilis (Category 5 landfall) (14 killed) ($135 million damage)

2000: Typhoon Xangsane (89 killed) ($500 million damage)

2001: Typhoon Toraji (214 killed) ($240 million damage)

2001: Typhoon Nari (104 killed) ($800 million damage) (Erratic path had Nari looping and then moving SW into Taiwan.)

2004: Typhoon Mindulle (45 killed) ($400 million damage)

[wxmann_91]

Starting to show up on radar



http://www.cwb.gov.tw/V5e/

[Normandy]

Thats a pretty good radar presentation.

[HURAKAN]

Pretty strong typhoon, even looking strong on radar.

[Normandy]

That inner eyewall should collapse pretty soon....the secondary eyewall looks fairly strong.

[Dave C]

I remember when Bonnie was moving towards North Carolina and it had a huge eye about
50+ miles across and the eroding inner eyewall was rotating around inside of it. This looks the same except more intense.

[Chacor]

WTPQ20 RJTD 171200
RSMC TROPICAL CYCLONE ADVISORY
NAME TY 0708 SEPAT (0708)
ANALYSIS
PSTN 171200UTC 21.8N 122.9E GOOD
MOVE NNW 08KT
PRES 940HPA
MXWD 090KT
GUST 130KT
50KT 90NM
30KT 270NM SOUTH 210NM NORTH
FORECAST
24HF 181200UTC 24.5N 119.8E 90NM 70%
MOVE NW 08KT
PRES 960HPA
MXWD 075KT
GUST 105KT
48HF 191200UTC 26.5N 117.4E 150NM 70%
MOVE NW 07KT
PRES 985HPA
MXWD 050KT
GUST 070KT
72HF 201200UTC 26.9N 114.5E 220NM 70%
MOVE W 07KT
PRES 998HPA
MXWD 035KT
GUST 050KT =

Weakened. Landfall now estimated to be in about 9-12 hours... which would be early morning local time.

[btangy]

Concentric eyewall remains. I'm surprised the inner eyewall has held on. Maybe there is enough distance between the inner and outer eyewalls for there to be enough surface fluxes and inflow to keep the inner eyewall going. The secondary radius of maximum winds is huge and a lot of people are going to be affected by Sepat. It'll be interesting to see how the topography interacts with the structure of Sepat, i.e. whether increased frictional convergence will cause the outer eyewall to contract.

[HurricaneBill]

Reminds me of Typhoon Winnie in 1997.

[HURAKAN]

Latest radar image.

[DESTRUCTION5]

Man the models nailed this one days ago!

[wxmann_91]

Man the models nailed this one days ago!

I remember one certain ECMWF 240hr plot... verified right to the teeth.

[cyclonic chronic]

landfall! based on taiwan radar the eyewall is crossing the coast. eye has filled in alot the past few hours, but sepat still looks like its gonna give taiwan a rough ride.

[Dave C]

I've noticed from reviewing the last several hrs of the radar that we've been watching that the part of the storm over the island is not showing up well due to mountains intercepting the radar beam. Must be incredible rains being rung out of this thing. The overall sat. appearence is so symetric considering it's half over the island and higher elevations

[P.K.]

The local tv forecasts were calling for over 1000mm in places from this earlier I'm told.

[tim_in_ga]

Over 300mm of rain has been recorded just from the outskirts of the typhoon, and it's not done yet! My in-laws near Taichung are starting to see the rain pick up.

[Aslkahuna]

Lan-Yu reported 10 min winds of 83 mph and a pressure of 976 hPa earlier today. That would equate to 90+ mph 1 minute winds which would imply gusts well over 100 mph.

Steve

[btangy]

Precip past 24 hours:

http://www.cwb.gov.tw/V5e/observe/rainf ... 30.EZJ.jpg

Maxed out at 300mm, but I've heard reports of 500mm+ (20"). It wouldn't surprise me if the total was much higher in the mountainous regions.

[Chacor]

Downgraded inland in China.

TS 0708 (SEPAT)
Issued at 00:00 UTC, 19 August 2007
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 0708 SEPAT (0708) DOWNGRADED FROM STS
ANALYSIS
PSTN 190000UTC 25.3N 118.5E GOOD
MOVE NW 06KT
PRES 990HPA
MXWD 045KT
GUST 065KT
30KT 240NM SOUTHEAST 150NM NORTHWEST
FORECAST
24HF 200000UTC 27.0N 117.0E 90NM 70% TROPICAL DEPRESSION