WPAC: HAISHEN - Post-Tropical

[euro6208]

We have Atlantic storms which run close to Dvorak (eg. Maria, Laura, Michael, etc.) and also some which are significantly higher (eg. Irma, Dorian, Matthew but its upgrade is strongly dependent on SFMR’s validity).

Simply throwing “Atlantic” doesn’t help. It just shows the intent to purposely overlook Atlantic storms which run close to Dvorak.

Run close to dvorak? They all peaked above dvorak and the nearest number/number higher.

Highest dvorak of 7.0 for Maria, 150 knots peak.

Highest dvorak of 6.5 for Michael, 140 knots peak.

Highest dvorak of 6.5 for Laura, 135 knots. (Probrably closest, but Haishen is more impressive and actually got a 7.0.)

Oooo, ok recon leads dvorak.

Can we also upgrade dependantly on sfmr?

I would like to challenge the members here. When was the last time a cat 4 and 5 atlantic system was behind 6.5 and 7.0 dvorak but had recon?

[aspen]

We have Atlantic storms which run close to Dvorak (eg. Maria, Laura, Michael, etc.) and also some which are significantly higher (eg. Irma, Dorian, Matthew but its upgrade is strongly dependent on SFMR’s validity).

Simply throwing “Atlantic” doesn’t help. It just shows the intent to purposely overlook Atlantic storms which run close to Dvorak.

Run close to dvorak? They all peaked above dvorak and the nearest number.

Highest dvorak of 7.0 for Maria, 150 knots peak.

Highest dvorak of 6.5 for Michael, 140 knots peak.

Highest dvorak of 6.5 for Laura, 135 knots. (Probrably closest, but Haishen is more impressive and actually got a 7.0.)

Oooo, ok recon leads dvorak.

Can we also upgrade dependantly on sfmr?

I would like to challenge the members here. When was the last time a cat 4 and 5 atlantic system was behind 6.5 and 7.0 dvorak but had recon?

I remember ADT was consistently hitting 140-145 kt when Michael peaked and was operationally assessed at 130-135 kt. ADT was also quite close to Laura’s 130-135 kt.

[NotoSans]

Michael's subjective Dvorak fix was T7.0 (not T6.5) from TAFB. From the same chart you can see best-track intensity (determined by recon) being consistently lower than ADT and SATCON.


Laura is 130kt by NHC. Perhaps post-season analysis will bump up to 135kt, but right now it's 130kt.

[euro6208]

Michael and Laura, i'd exclude them.

Anymore?

[NotoSans]

Recon still lead all, I'm talking about dvorak fixes not ADT and SATCON.

Look at the blue squares in the chart. Subjective Dvorak fixes are still higher than best-track intensity determined by recon. The "Highest T is 6.5 from Michael" is plainly inaccurate.

Of course it would be better to have recon, but there is no ground to say "Dvorak fixes always underestimate storms". After all, how many Atlantic Cat.5 have we seen over the past few years? How is a sample of less than 10 significant?

[euro6208]

Recon still lead all, I'm talking about dvorak fixes not ADT and SATCON.

Look at the blue squares in the chart. Subjective Dvorak fixes are still higher than best-track intensity determined by recon. The "Highest T is 6.5 from Michael" is plainly inaccurate.

Of course it would be better to have recon, but there is no ground to say "Dvorak fixes always underestimate storms". After all, how many Atlantic Cat.5 have we seen over the past few years? How is a sample of less than 10 significant?

How about Irma, Dorian, Matthew?

[ElectricStorm]

Recon still lead all, I'm talking about dvorak fixes not ADT and SATCON.

Look at the blue squares in the chart. Subjective Dvorak fixes are still higher than best-track intensity determined by recon. The "Highest T is 6.5 from Michael" is plainly inaccurate.

Of course it would be better to have recon, but there is no ground to say "Dvorak fixes always underestimate storms". After all, how many Atlantic Cat.5 have we seen over the past few years? How is a sample of less than 10 significant?

How about Irma, Dorian, Matthew?

I think Matthew actually has a chance to be downgraded to a cat 4 in reanalysis as they upgraded based on a single SFMR and I believe I have seen that SFMR overestimates storms a bit at that intensity. Dorian was the exception, not the norm. But it would be nice to have recon in the WPAC to see just how strong these storms really are.

[mrbagyo]

No doubt a Cat 5. Recon would probably find 140-150 kt. However, while Haishen has joined the league of extremely intense "Ha"-named WPac typhoons, it's not nearly at the same level as Haiyan, Hagupit, Hagibis, or Halong. This is more of your run-of-the-mill low end WPac Cat 5, similar to Haima.
https://i.imgur.com/a8khtrW.png

No disrespect to Haishen, but the Cat5's originating from the WPAC deep tropics (south of 20N and east of 130E) are a different league. Perhaps those typhoons had more potential and advantages from the get-go, given their initial position.

I agree, Haishen's high latitude location is no longer conducive for production of CDG cloudtops. Minami's latest sounding indicates it could support up to CMG only

[aspen]

Haishen is still pulling off a full W ring and a >+19C eye. If it can hold this for just a few more hours, perhaps the JTWC will upgrade it to a Cat 5 at 18z.

[mrbagyo]

Given the potential impact of this storm to Japan and South Korea, I hope Japan would send a recon plane into Haishen's core just like what they did to Typhoon Lan way back in 2017 - University of Nagoya and University of Ryukyu lead that mission

T-PARCII - (Tropical cyclones-Pacific Asian Research Campaign for Improvement of Intensity estimations/forecasts)

[ElectricStorm]

Haishen is still pulling off a full W ring and a >+19C eye. If it can hold this for just a few more hours, perhaps the JTWC will upgrade it to a Cat 5 at 18z.

I've noticed that on some storms lately, including Maysak, they seem to wait until after it's peaked and starting do weaken to upgrade it to peak intensity for some reason

[euro6208]

Haishen is still pulling off a full W ring and a >+19C eye. If it can hold this for just a few more hours, perhaps the JTWC will upgrade it to a Cat 5 at 18z.

I've noticed that on some storms lately, including Maysak, they seem to wait until after it's peaked and starting do weaken to upgrade it to peak intensity for some reason

Yup that's dvorak catching up. They cannot go higher.

Dvorak limiting the intensity.

It's all rules and beauty.

[Highteeld]

That should just about do it

[euro6208]

I'd personally set it at 155 knots based on similiar systems.

[ElectricStorm]

I'd personally set it at 155 knots based on similiar systems.

While I definitely think this a a cat 5 for sure (I bet they'll upgrade at 18z) I don't think it's 155 kts. Right now it's probably 140-145 kts

[aspen]

Haishen is still pulling off a full W ring and a >+19C eye. If it can hold this for just a few more hours, perhaps the JTWC will upgrade it to a Cat 5 at 18z.

I've noticed that on some storms lately, including Maysak, they seem to wait until after it's peaked and starting do weaken to upgrade it to peak intensity for some reason

They did that with Bualoi as well, which they horribly underestimated. It was easily a Cat 5 like Haishen and probably got up to 150 kt (according to a well-timed SMAP pass). The JTWC assessed peak appearance — a 19C eye with a very thick W ring — as a 120 kt Cat 4, and once an EWRC was clearly taking its toll, they upgraded it to 125 kt.

[ElectricStorm]

Haishen is still pulling off a full W ring and a >+19C eye. If it can hold this for just a few more hours, perhaps the JTWC will upgrade it to a Cat 5 at 18z.

I've noticed that on some storms lately, including Maysak, they seem to wait until after it's peaked and starting do weaken to upgrade it to peak intensity for some reason

They did that with Bualoi as well, which they horribly underestimated. It was easily a Cat 5 like Haishen and probably got up to 150 kt (according to a well-timed SMAP pass). The JTWC assessed peak appearance — a 19C eye with a very thick W ring — as a 120 kt Cat 4, and once an EWRC was clearly taking its toll, they upgraded it to 125 kt.

Yeah hopefully they upgrade Bualoi in the final best track. Didn't they also do that with Halong? Wasn't that one like T7.8 and they only upgraded to 155kts after it was already weakening

[mrbagyo]

JMA is still calling for a violent phoon by tomorrow
TY 2010 (Haishen)
Issued at 12:50 UTC, 4 September 2020

<Analysis at 12 UTC, 4 September>
Scale -
Intensity Very strong
Center position N22°40' (22.7°)
E133°30' (133.5°)
Direction and speed of movement WNW 15 km/h (9 kt)
Central pressure 920 hPa
Maximum wind speed near center 50 m/s (100 kt)
Maximum wind gust speed 70 m/s (140 kt)
≥ 50 kt wind area ALL 220 km (120 NM)
≥ 30 kt wind area NE 500 km (270 NM)
SW 440 km (240 NM)

<Forecast for 00 UTC, 5 September>
Intensity Violent
Center position of probability circle N23°40' (23.7°)
E132°00' (132.0°)
Direction and speed of movement NW 15 km/h (9 kt)
Central pressure 920 hPa
Maximum wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of probability circle 45 km (25 NM)
Storm warning area ALL 270 km (145 NM)

<Forecast for 12 UTC, 5 September>
Intensity Violent
Center position of probability circle N25°00' (25.0°)
E131°10' (131.2°)
Direction and speed of movement NNW 15 km/h (8 kt)
Central pressure 915 hPa
Maximum wind speed near center 55 m/s (110 kt)
Maximum wind gust speed 80 m/s (155 kt)
Radius of probability circle 65 km (35 NM)
Storm warning area ALL 310 km (165 NM)

<Forecast for 12 UTC, 6 September>
Intensity Violent
Center position of probability circle N29°55' (29.9°)
E129°25' (129.4°)
Direction and speed of movement NNW 25 km/h (13 kt)
Central pressure 920 hPa
Maximum wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of probability circle 110 km (60 NM)
Storm warning area ALL 330 km (180 NM)

<Forecast for 12 UTC, 7 September>
Intensity -
Center position of probability circle N38°25' (38.4°)
E128°20' (128.3°)
Direction and speed of movement N 40 km/h (21 kt)
Central pressure 960 hPa
Maximum sustained wind speed 35 m/s (65 kt)
Maximum wind gust speed 50 m/s (95 kt)
Radius of probability circle 185 km (100 NM)
Storm warning area ALL 310 km (170 NM)

<Forecast for 12 UTC, 8 September>
Intensity -
LOW
Center position of probability circle N44°35' (44.6°)
E127°35' (127.6°)
Direction and speed of movement N 30 km/h (16 kt)
Central pressure 984 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of probability circle 260 km (140 NM)

[aspen]

I've noticed that on some storms lately, including Maysak, they seem to wait until after it's peaked and starting do weaken to upgrade it to peak intensity for some reason

They did that with Bualoi as well, which they horribly underestimated. It was easily a Cat 5 like Haishen and probably got up to 150 kt (according to a well-timed SMAP pass). The JTWC assessed peak appearance — a 19C eye with a very thick W ring — as a 120 kt Cat 4, and once an EWRC was clearly taking its toll, they upgraded it to 125 kt.

Yeah hopefully they upgrade Bualoi in the final best track. Didn't they also do that with Halong? Wasn't that one like T7.8 and they only upgraded to 155kts after it was already weakening

Oh yeah, I forgot Halong was another late upgrade. The 12z update was 140 kt despite ADT supporting 160-165 kt, and they didn’t upgrade to 155 kt until 18z and an EWRC was starting. Dvorak was still >T#7.5 by then.

[aspen]

An outer eyewall is forming, but as of the 12z pass, it’s rather thin. Still, an EWRC is mere hours away.