WPAC: YAGI - Post-Tropical

[ElectricStorm]

12W YAGI 240905 0000 19.1N 115.8E WPAC 130 922

JTWC agrees first super typhoon of the season although Shanshan may have been one at peak

[xtyphooncyclonex]

Now the strongest storm of the season, and strongest in the SCS since Rai.

T2411(Yagi)
Issued at 2024/09/05 00:35 UTC
Analysis at 09/05 00 UTC
Grade TY
Scale -
Intensity Violent
Center position N19°00′ (19.0°)
E115°50′ (115.8°)
Direction and speed of movement W Slow
Central pressure 915 hPa
Maximum sustained wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of 50-kt wind area 165 km (90 NM)
Radius of 30-kt wind area 330 km (180 NM)

[cycloneye]

12W YAGI 240905 0000 19.1N 115.8E WPAC 130 922

[Hurricane2022]

EWRC will likely start in the next few hours.

[Hurricane2022]

<Forecast for 09 JST, 2024/09/06>

Intensity/Category Violent Typhoon

Center Position 19.8N 112.8E

Direction and speed of movement WNW 15km/h (7kt)

Central pressure 905hPa

Maximum wind speed near center 55m/s (110kt)

Maximum wind gust speed 80m/s (155kt)

Radius of probability circle 65km (35NM)

Storm warning area ALL 290km (155NM)

[ElectricStorm]

Really taking a hit now. Likely peaked around 130kts earlier but not may already be below 115kts if ADT is to be believed.

[doomhaMwx]

Today's round of recon mission into Yagi from HKO. The data feed was cut/turned off as they approached the storm, but they probably penetrated the eye/eyewall this time. The aircraft is now en route back to Hong Kong.

[doomhaMwx]

Recon recorded an SLP of 931.5 mb in the eyewall at 04Z.

 https://x.com/CyanideCN_/status/1831598598896697581

[kevin]

Yagi likely peaked around 22z - 00z. Here are the peak intensity estimates for that time.

ADT = 919 mb, 135 kt (22:00z)
AiDT = 134 kt (22:20z)
DPRINT = 916 mb, 135 kt (22:00z)
DMINT = 917 mb, 130 kt (17:58z)
SATCON = 919 mb, 138 kt (22:20z)

Recon measured 931.5 mb at 04z with 54 kt winds, which translates to a pressure estimate of 926 mb. Using the 5 intensity estimates at 04z would result in a mean estimate of (922, 922, 932, 930) = 926.5 mb, which to me seems to indicate that a blend of the intensity estimates is quite reasonable for the true intensity. As such taking the mean at peak intensity results in a peak of 918 mb and 135 kt. Or in NATL terms it's one of those 135 kt storms where we would be arguing for weeks whether it was actually 135 kt or 140 kt . Either way, hopefully it continues weakening as it approaches land.

I hope there will be more WPAC recon flights in the future, this sort of data is very valuable for real-time intensity tracking, historic bookkeeping and to validate other intensity methods. It also makes traditionally conservative agencies (intensity-wise) like JMA more confidence to issue high-end advisories for typhoons. And as a weather enthusiast it's also just very interesting of course.

[Hayabusa]

A 04/22Z SMAP pass gives 119 kt 10 min wind which translates to one minute 128 kt winds

WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 34, NEQ, 0, 130, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 50, NEQ, 71, 75, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 64, NEQ, 49, 57, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained

[kevin]

A 04/22Z SMAP pass gives 119 kt 10 min wind which translates to one minute 128 kt winds

WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 34, NEQ, 0, 130, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 50, NEQ, 71, 75, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 12, 202409042209, 30, SMAP, IR, , 1910N, 11580E, , 1, 119, 1, , , , 64, NEQ, 49, 57, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained

A blend of the intensity estimates at 04z gives a wind speed of 125 kt, a little below the measures values. If this underestimate is consistent during the last 24 hours then Yagi may have been closer to 140 kt than 135 kt at peak intensity.

[xtyphooncyclonex]

Yagi's northern side almost eroded earlier, but it seems to have started to rebound a bit.

Eye looks to have become more and more rounded by frame.

[cycloneye]

Recon was there.

 https://x.com/CyanideCN_/status/1831598598896697581

[Kingarabian]

Likely peaked as a cat.5 then based on that dropsonde.

[xtyphooncyclonex]

Yagi looks stronger than ever.

[cheezyWXguy]

Definitely got its act back together. Did the erc ever actually occur? The eye size looks about the same as before

[mrbagyo]

Xisha radar

[Teban54]

That's quite a comeback.

[xtyphooncyclonex]

As the JTWC forecasts insists on weakening, the JMA, CMA and HKO all expect Yagi to strengthen upon its landfall. The second eyewall appears to have dominated in what appears to be a meld. Barring any ERC, this doesn't bode well for the Leizhou peninsula and Hainan.

[ElectricStorm]

Wow what a rebound. Probably back up to around 130kts now. Could be a Cat 5 soon if this sustains and the eye gets a little warmer