WPAC: LAN - Typhoon

[GCANE]

 https://twitter.com/iCyclone/status/922159492573384706




 https://twitter.com/iCyclone/status/922161309990440961




 https://twitter.com/iCyclone/status/922168963609583616

[euro6208]

A direct hit for Tokyo.

[doomhaMwx]

Lan is now an ExtraTropical Cyclone, or very close to one, centered off the east coast of Japan...

STS 1721 (Lan)
Issued at 00:45 UTC, 23 October 2017

<Analysis at 00 UTC, 23 October>
Scale Very large
Intensity -
Center position N37°30' (37.5°)
E141°35' (141.6°)
Direction and speed of movement NE 75 km/h (40 kt)
Central pressure 970 hPa
Maximum sustained wind speed 30 m/s (60 kt)
Maximum wind gust speed 45 m/s (85 kt)
≥ 50 kt wind area N 390 km (210 NM)
S 280 km (150 NM)
≥ 30 kt wind area ALL 1100 km (600 NM)

[mrbagyo]

thats a huge area of > 30 knot wind -
2200 kms in diameter

[doomhaMwx]

At least 5 dead in Japan... Damages/casualties mostly due to heavy rainfall...

TOKYO (Kyodo) -- Powerful Typhoon Lan made landfall on the Pacific coast of central Japan early Monday, leaving at least five people dead as it battered a wide area with heavy rain and strong winds.

The typhoon, which hit Shizuoka Prefecture around 3 a.m., caused floods and mudslides as it traveled along the Pacific coast of the largest main island of Honshu.

With an atmospheric pressure of 950 hectopascals at its center and winds of up to 198 kilometers per hour, the season's 21st typhoon brought particularly heavy rainfall in the western region, dumping 800 millimeters in the 48 hours to Sunday evening in Wakayama Prefecture and 700 mm in Mie Prefecture, the Japan Meteorological Agency said.

https://mainichi.jp/english/articles/20 ... dm/005000c

[doomhaMwx]

LOW
Issued at 06:45 UTC, 23 October 2017

<Analysis at 06 UTC, 23 October>
Scale -
Intensity -
LOW
Center position N41°00' (41.0°)
E146°00' (146.0°)
Direction and speed of movement NE 75 km/h (40 kt)
Central pressure 970 hPa

[1900hurricane]

I got a 126 kt intensity for Lan near peak intensity using the measured 923 mb and JTWC data from 18Z October 21st. That's also 111 kt using standard 10 minute winds or 100 kt using the corresponding 10 minute winds from the Koba table.

Using a 923 mb central pressure, 18 kt forward speed,
272 nm average TS radius, and 25.5º latitude, KZC outputs
a 126 kt 1 min wind velocity with an OCI of 1006 mb.

However, the recon 923 mb pass didn't come until 01Z, October 19, when Lan was visibly degrading. The actual pressure at 18Z may have been in the 915-920 mb range. Coupled with the other given information above, 915 mb spits out 135 kt.

[NotoSans]

JMA released Lan's best track today and the estimated peak intensity was revised to 915mb/100kt.

[NotoSans]

http://www.u-ryukyu.ac.jp/univ_info/ann ... 073001.pdf (in Japanese)

The Meteorological Research Institute (MRI) under JMA has recently published the recon results for LAN, after conducting quality control. Central pressure of 925 and 930 mb were recorded by dropsondes at 0652Z, October 21 and 0115Z, October 22 respectively. Note that the latter dropsonde did not fall exactly in the eye and was approximately 10 km from the estimated center.

The MRI planned to conduct one recon mission per year over the coming three years (2018 - 2020).