WPAC: LAN - Typhoon

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Re: WPAC: LAN - Typhoon

#141 Postby xtyphooncyclonex » Sat Oct 21, 2017 7:40 am

This storm has just probably done history, unnoticed. According to Digital Typhoon, Lan is the largest tropical cyclone on record, tied with Tip at 1900 km diameter for gale-force winds, and higher than Tip in storm-force winds at 750 km vs 560 km for the latter.

Thanks to this storm enhancing the monsoon, the Visayas has been deluged with copious amounts of rain.

http://news.abs-cbn.com/news/10/20/17/p ... y-declared
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Re: WPAC: LAN - Typhoon

#142 Postby xtyphooncyclonex » Sat Oct 21, 2017 7:42 am

euro6208 wrote:Too bad there's no more recon.

JMA did two recon missions on Lan. Pressure is 925 hPa, look at page 7 (posted by NotoSans)

Winds near the ground are 70 m/s, roughly 157 mph. This may be upgraded to a category 5
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Re: WPAC: LAN - Typhoon

#143 Postby euro6208 » Sat Oct 21, 2017 7:54 am

Still boggles me how Irma and Maria got up to upper end Cat 5 with a dvorak of only 6.0 and 6.5 (Both Cat 4 not just them but there a couple) and yet Lan had 7.0 but wasn't upgraded to a Cat 5 at all. Talk about some screwd comparison.
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Re: WPAC: LAN - Typhoon

#144 Postby Imran_doomhaMwx » Sat Oct 21, 2017 8:13 am

euro6208 wrote:Still boggles me how Irma and Maria got up to upper end Cat 5 with a dvorak of only 6.0 and 6.5 (Both Cat 4 not just them but there a couple) and yet Lan had 7.0 but wasn't upgraded to a Cat 5 at all. Talk about some screwd comparison.

Uhm, because recon found a Cat 5 even though dvorak values didn't match... Why would you go with dvorak estimates if you have recon measurements available?
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Re: WPAC: LAN - Typhoon

#145 Postby euro6208 » Sat Oct 21, 2017 8:16 am

Imran_doomhaMwx wrote:
euro6208 wrote:Still boggles me how Irma and Maria got up to upper end Cat 5 with a dvorak of only 6.0 and 6.5 (Both Cat 4 not just them but there a couple) and yet Lan had 7.0 but wasn't upgraded to a Cat 5 at all. Talk about some screwd comparison.

Uhm, because recon found a Cat 5 even though dvorak values didn't match... Why would you go with dvorak estimates if you have recon measurements available?


Well it goes to show that dvorak estimates are useless in powerful cyclones.

Why would you go with dvorak estimates if you have recon measurements available?


Exactly. In the WPAC, you see all of these Irma's and Maria's yet they are measured low because dvorak is very low. When you have recon, you will always find a stronger cyclone.
Last edited by euro6208 on Sat Oct 21, 2017 8:26 am, edited 1 time in total.
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Re: WPAC: LAN - Typhoon

#146 Postby NotoSans » Sat Oct 21, 2017 8:24 am

Dvorak estimates for Maria were at T7.0 range when recon reported maximum sustained winds of around 150 kn. And, despite lower central pressure and higher Dvorak estimates, Irma had higher maximum sustained wind speeds than Maria (Subjective Dvorak number never reach T7.0 for Irma). This has already proven that higher Dvorak estiamtes would not necessarily yield higher wind speeds.

Recon reported a central pressure of around 925 hPa, while that of Irma and Maria were 914 hPa and 908 hPa. Pressure wise, Lan is weaker than Irma and Maria. With such a large circulation, it is nearly impossible for Lan to reach category 5, and dropsonde winds were likely representative of gusts instead of sustained winds.
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Re: WPAC: LAN - Typhoon

#147 Postby euro6208 » Sat Oct 21, 2017 8:36 am

NotoSans wrote:Dvorak estimates for Maria were at T7.0 range when recon reported maximum sustained winds of around 150 kn. And, despite lower central pressure and higher Dvorak estimates, Irma had higher maximum sustained wind speeds than Maria (Subjective Dvorak number never reach T7.0 for Irma). This has already proven that higher Dvorak estiamtes would not necessarily yield higher wind speeds.

Recon reported a central pressure of around 925 hPa, while that of Irma and Maria were 914 hPa and 908 hPa. Pressure wise, Lan is weaker than Irma and Maria. With such a large circulation, it is nearly impossible for Lan to reach category 5, and dropsonde winds were likely representative of gusts instead of sustained winds.


So Maria reached 7.0 and Irma didn't yet recon found both to be upper end Cat 5.

This is what i'm about talking. A typhoon of 6.5 or 7.0 could be stronger than what the agencies are saying.
Last edited by euro6208 on Sat Oct 21, 2017 8:38 am, edited 1 time in total.
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Re: WPAC: LAN - Typhoon

#148 Postby NotoSans » Sat Oct 21, 2017 8:38 am

euro6208 wrote:
NotoSans wrote:Dvorak estimates for Maria were at T7.0 range when recon reported maximum sustained winds of around 150 kn. And, despite lower central pressure and higher Dvorak estimates, Irma had higher maximum sustained wind speeds than Maria (Subjective Dvorak number never reach T7.0 for Irma). This has already proven that higher Dvorak estiamtes would not necessarily yield higher wind speeds.

Recon reported a central pressure of around 925 hPa, while that of Irma and Maria were 914 hPa and 908 hPa. Pressure wise, Lan is weaker than Irma and Maria. With such a large circulation, it is nearly impossible for Lan to reach category 5, and dropsonde winds were likely representative of gusts instead of sustained winds.


So Maria reached 7.0 and Irma didn't yet recon found an upper end Cat 5.

This is what i'm about talking. A typhoon of 6.5 or 7.0 could be stronger than what the agencies are saying.


But it can also be weaker. The truth is that Dvorak has errors, but it is not that recon will always find a stronger cyclone than what Dvorak indicates.
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Re: WPAC: LAN - Typhoon

#149 Postby euro6208 » Sat Oct 21, 2017 8:41 am

I would love to find the most impressive satellite of Irma and Maria's when they are at peak and when they are christened as a Cat 5 and compare them to the typhoons when they were at peak and when they were christened as a Cat 5. I bet those typhoons especially the 140 knot one because of dvorak 7.0, will look more powerful than them. Sad that 7.0 using satellite is the gateway to a Cat 5. In the Atlantic it's 6.0 or 6.5.
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Re: WPAC: LAN - Typhoon

#150 Postby mrbagyo » Sat Oct 21, 2017 9:45 am

Lan's Eye temperature has been 20℃ + for more than 12 consecutive hours already.
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Re: WPAC: LAN - Typhoon

#151 Postby GCANE » Sat Oct 21, 2017 10:16 am

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Re: WPAC: LAN - Typhoon

#152 Postby Alyono » Sat Oct 21, 2017 10:17 am

Euro,

Recon conclusively found lan much weaker than irma and maria. End of story
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Re: WPAC: LAN - Typhoon

#153 Postby GCANE » Sat Oct 21, 2017 10:18 am

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Re: WPAC: LAN - Typhoon

#154 Postby GCANE » Sat Oct 21, 2017 10:22 am

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Re: WPAC: LAN - Typhoon

#155 Postby xtyphooncyclonex » Sat Oct 21, 2017 10:41 am

euro6208 wrote:I would love to find the most impressive satellite of Irma and Maria's when they are at peak and when they are christened as a Cat 5 and compare them to the typhoons when they were at peak and when they were christened as a Cat 5. I bet those typhoons especially the 140 knot one because of dvorak 7.0, will look more powerful than them. Sad that 7.0 using satellite is the gateway to a Cat 5. In the Atlantic it's 6.0 or 6.5.

The difference is, recon found 135 kts and 925 hPa for Lan..... This means not all storms are "way stronger" than what you think. But I'd still say 140 kts is reasonable (70m/s, 157 mph is in between but is a cat 5) IMO, not a hyperbolic intensity. Like what we've stated several times: not all storms are underestimated by Dvorak.

Want Dvorak? Plane penetrated into Lan's eye and voila...
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Re: WPAC: LAN - Typhoon

#156 Postby 1900hurricane » Sat Oct 21, 2017 11:18 am

With Lan now at ~25*N, it is now north of the axis of the primary steering subtropical ridge and beginning to enter the fringes of mid-latitude flow. This has started to become apparent on satellite imagery. Southwesterly shear is beginning to affect the typhoon, and it will only increase from here as it draws closer to the right entrance region of a standing jet streak. Right entrance regions are highly divergent, so it won’t be an instant demise, but Lan is clearly now past peak intensity.
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Re: WPAC: LAN - Typhoon

#157 Postby CrazyC83 » Sat Oct 21, 2017 11:47 am

xtyphooncyclonex wrote:
euro6208 wrote:Too bad there's no more recon.

JMA did two recon missions on Lan. Pressure is 925 hPa, look at page 7 (posted by NotoSans)

Winds near the ground are 70 m/s, roughly 157 mph. This may be upgraded to a category 5


Is that 10-min sustained or 1-min sustained? If 10-min, that would support about 150 kt. But if 1-min, then 135 kt is reasonable.
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Re: WPAC: LAN - Typhoon

#158 Postby tolakram » Sat Oct 21, 2017 12:28 pm

euro6208 wrote:I would love to find the most impressive satellite of Irma and Maria's when they are at peak and when they are christened as a Cat 5 and compare them to the typhoons when they were at peak and when they were christened as a Cat 5. I bet those typhoons especially the 140 knot one because of dvorak 7.0, will look more powerful than them. Sad that 7.0 using satellite is the gateway to a Cat 5. In the Atlantic it's 6.0 or 6.5.


You got into this same argument in the ACE thread. This is the same post you've made over and over so I'm telling you right now, get over it. If you can't stay on the topic of Lan then stop posting.
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Re: WPAC: LAN - Typhoon

#159 Postby supercane4867 » Sat Oct 21, 2017 12:41 pm

CrazyC83 wrote:
xtyphooncyclonex wrote:
euro6208 wrote:Too bad there's no more recon.

JMA did two recon missions on Lan. Pressure is 925 hPa, look at page 7 (posted by NotoSans)

Winds near the ground are 70 m/s, roughly 157 mph. This may be upgraded to a category 5


Is that 10-min sustained or 1-min sustained? If 10-min, that would support about 150 kt. But if 1-min, then 135 kt is reasonable.

I believe that data came from a dropsonde, which measures instantaneous gusts rather than sustained winds.
I don't think they have SFMR instrument to directly measure sustained winds at surface level anyway.
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Re: WPAC: LAN - Typhoon

#160 Postby GCANE » Sat Oct 21, 2017 1:30 pm

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 21 OCT 2017 Time : 174000 UTC
Lat : 25:25:03 N Lon : 133:11:44 E

CI# /Pressure/ Vmax
6.6 / 928.1mb/129.6kt

Final T# Adj T# Raw T#
6.6 7.0 7.0

Image
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