Super Typhoon Haiyan (split from WPac thread)

[eyewall]

Well Josh has come in with a pressure data. 960mb was bout 40mb higher than I was expecting for being about 3 miles outside the eye and 10 miles from the exact center.

 

Warning I'm not a met, but:

I doubt there was a 100mb pressure drop in 10 miles. The central pressure may very well have only been around 910mb or higher.   That would still leave room for an insane pressure gradient in the eyewall. Also since it was at a lower latitude only around 11N much stronger wind speeds are possible. 

 

That would explain why the wind damage is about the worst I've ever seen with a TC.

 

It was a very compact system so the pressure gradient from eyewall to eye would be much greater than a lot of storms. Charley was a good example of that, but certainly not 100mb from eyewall to center of the eye. It is doubtful the central pressure was below 900 when Josh saw his lowest reading. The storm likely began filling by then as it started to feel the effects of land interaction. With this in mind prior to land 890's may not be all that far off (such as JTWC's estimate).

[Ensō]

From an AP article "Looters raided grocery stores and gas stations in search of food, fuel and water as the government began relief efforts and international aid operations got underway."

That's not my definition of looters. That's my definition of survivors. Bad choice of words. Looters carry tvs merchandise and other non life essential things from stores.

 

Yeah, I'm not sure what they expect people to do. I don't think many people would sit idly by while they and their families starved and/or dehydrated if they knew there are supplies nearby. I certainly wouldn't.

[patrick05]

Well Josh has come in with a pressure data. 960mb was bout 40mb higher than I was expecting for being about 3 miles outside the eye and 10 miles from the exact center.

 

Warning I'm not a met, but:

I doubt there was a 100mb pressure drop in 10 miles. The central pressure may very well have only been around 910mb or higher.   That would still leave room for an insane pressure gradient in the eyewall. Also since it was at a lower latitude only around 11N much stronger wind speeds are possible. 

 

That would explain why the wind damage is about the worst I've ever seen with a TC.

 

Edit: Josh was more like 13-15 miles from the exact center.

 

 

It was a very compact system so the pressure gradient from eyewall to eye would be much greater than a lot of storms. Charley was a good example of that, but certainly not 100mb from eyewall to center of the eye. It is doubtful the central pressure was below 900 when Josh saw his lowest reading. The storm likely began filling by then as it started to feel the effects of land interaction. With this in mind prior to land 890's may not be all that far off (such as JTWC's estimate).

 

but remember that Tacloban Airport was still reporting a couple hours before the worst conditions came in and it was already reporting a pressure of 955hPa.. the pressure couldn't have risen as the eyewall pushed across could it?? i'm not questioning Josh's measurement btw, it could also be that the instrument in Tacloban was a little off; but just surprised with that figure i would've expected much lower reading than that..

[Amped]

but remember that Tacloban Airport was still reporting a couple hours before the worst conditions came in and it was already reporting a pressure of 955hPa.. the pressure couldn't have risen as the eyewall pushed across could it?? i'm not questioning Josh's measurement btw, it could also be that the instrument in Tacloban was a little off; but just surprised with that figure i would've expected much lower reading than that..

 

Yeah that pressure reading just doesn't make sense. I know "916" has a habit of sounding a lot like "960" so I'll wait for someone from the chase team to confirm it a second time.

[ncforecaster89]

The fact we didn't have any recon obs, the validity of the JTWC MSW estimate is always going to be left to debate. Although the wind damage is very significant, it's the incredible surge damage that is so evident in the pics we are seeing.

[eyewall]

but remember that Tacloban Airport was still reporting a couple hours before the worst conditions came in and it was already reporting a pressure of 955hPa.. the pressure couldn't have risen as the eyewall pushed across could it?? i'm not questioning Josh's measurement btw, it could also be that the instrument in Tacloban was a little off; but just surprised with that figure i would've expected much lower reading than that..

 

We should probably deem it as inconclusive for now. Obviously it would not rise before the center makes its closest approach. I don't know the standard error of the instrument he is using. We also don't know if it was calibrated properly. The same goes for the airport ob.

[TropicalAnalystwx13]

This blog entry was created the day of landfall. I'm not sure how credible it is, but it mentions a barometric pressure reading of 889mb at 5:01am local time (the eye was passing over at that time) on Guiuan as measured by a handheld. I have a hard time believing the pressure rose 60-70mb in the timespan between when the eye passed over Guiuan and it hit Leyte province, though it likely did rise a good bit due to land interaction.

[Typhoon Tip]

This blog entry was created the day of landfall. I'm not sure how credible it is, but it mentions a barometric pressure reading of 889mb at 5:01am local time (the eye was passing over at that time) on Guiuan as measured by a handheld. I have a hard time believing the pressure rose 60-70mb in the timespan between when the eye passed over Guiuan and it hit Leyte province, though it likely did rise a good bit due to land interaction.

 

With winds of 180+ raging?   That mass has got to go somewhere.  

[Typhoon Tip]

The idea of comparing to tornado damage just doesn't work regardless. There's not much of a vertical component, and although TC winds can be very dynamic and gusty, they aren't really comparable to the sudden, violent accelerations and directional shifts seen in tornadoes. I'd imagine debris loading wouldn't be nearly the same either, and that's a significant part of how tornadoes cause damage.

 

It'd be convenient to use the EF-scale as a rough guide, but it doesn't work. I don't think there's any way to reliably estimate the intensity from the photos and video we've seen anyway, at least not without a lot more information. I do think we can safely say it was extremely violent and some areas probably experienced winds above (possibly well above) the Cat. 5 threshold.

 

It's a reasonably debatable.   

 

EF4 166–200 

EF5 >200

 

Considering they sustained between 180 and 195 mph, as expected impact passing across the area, and that gusts were to 230mph, for a couple-few hours, I am not sure one could dismiss the idea.  Particularly ... the average EF4/5 tornado does not spend much more than a couple -a few moments in one location.  

 

There have been reports of tree bark stripping and edifices scoured from the Earth.  Not sure what else one can call that.

 

But yeah, more information is better here.     

[Ensō]

There's no harm in trying to use the EF-scale as a rough proxy, but IMO there are far too many variables for it to be useful as anything other than an interesting discussion. The comparison would assume that wind is wind, but the winds really are very different. The debris loading is probably the most significant difference, but also the radical difference in vertical velocity, sudden accelerations/wind shifts, etc. I'd wager that a hypothetical 200 mph tropical cyclone, while obviously extraordinarily devastating, would not produce wind damage nearly as intense as a "200 mph" EF5 tornado. And we also don't really know whether those EF-scale wind speed ranges are appropriate (they're mostly just well-informed guesses), and I think many of us suspect that the higher end of the range is probably substantially underestimated. It's still not a bad place to start a discussion, but it doesn't tell us much.

 

Anyhow, the bigger point is the lack of information. There obviously was debarking and denuding of trees, for example, but that doesn't tell us a whole lot. Some trees are much easier to strip than others. One thing that immediately comes to mind for me is the trees in Bangladesh. I have photos from several Bangladeshi tornadoes, and it seems that many trees are left stripped bare even in what would otherwise appear to be modest (F2?) tornadoes. I don't know how similar the trees are in these regions, but you get the idea.

 

Not that I'm arguing against Haiyan's intensity, by the way. As I said, I wouldn't doubt that some areas experienced winds well beyond the Category 5 threshold, and the damage is obviously massive. Just saying that we probably can't learn much about the intensity from photos, especially ones without context and additional information.

[Amped]

This blog entry was created the day of landfall. I'm not sure how credible it is, but it mentions a barometric pressure reading of 889mb at 5:01am local time (the eye was passing over at that time) on Guiuan as measured by a handheld. I have a hard time believing the pressure rose 60-70mb in the timespan between when the eye passed over Guiuan and it hit Leyte province, though it likely did rise a good bit due to land interaction.

 

Exactly, that's why I am keeping my money on the 916 960 switcharoo. Would not be the first time that's happened if that turns out to be the case.

 

Edit: The point I'm getting at in my last two posts is I don't believe the 960mb just yet. it can easily be a mixup or typo.  If anyone has the video or post where it originated from, feel free to link it. And yeah, 916mb would make a lot more sense.

[jordanwx]

Well Josh has come in with a pressure data. 960mb was bout 40mb higher than I was expecting for being about 3 miles outside the eye and 10 miles from the exact center.

 

Warning I'm not a met, but:

I doubt there was a 100mb pressure drop in 10 miles. The central pressure may very well have only been around 910mb or higher.   That would still leave room for an insane pressure gradient in the eyewall. Also since it was at a lower latitude only around 11N much stronger wind speeds are possible. 

 

That would explain why the wind damage is about the worst I've ever seen with a TC.

 

Edit: Josh was more like 13-15 miles from the exact center.

Impossible to know. One thing is for sure, the storm certainly weakened before reaching Tacloban based off MW and Radar imagery. So, even if it was only 910mb as it passed Tacloban, it could have been 20-30mb deeper at its peak.

[Tullioz]

Below are two articles that show the destruction and dire situation of the people in Guiuan which many are overlooking with all the attention being focused on Tacloban. I hope some more of you will help me to reach this area so that we can at least get some of the very basics to the people there. Was hoping to head out today but the lack of funds and bad weather have prevented that. 

 

http://www.theepocht...a-hits/?photo=2

 

http://www.rappler.c...r-damage-photos

 

 

 

http://www.americanwx.com/bb/index.php/topic/41654-relief-effort-for-those-affected-by-typhoon-haiyan/

[thewxmann]

It's almost impossible to compare hurricane winds and tornado winds. In hurricanes, the pressure gradient forces act horizontally and on the scales of tens of miles. In tornadoes, the pressure gradient forces act horizontally and vertically and on the scales of only a couple of miles at most.

 

Thus, the energy density is much greater in tornadoes. The stresses placed on structures, and the debris loading due to structural failure, is much greater in tornadoes. The frictional effect, meanwhile, is much less significant in tornadoes.

 

Even though Haiyan came in nearly at peak strength, the friction from all the trees and hills in the region almost certainly means places like Tacloban and Guiuan did not receive legitimate Cat 5 conditions.

[andyhb]

It's almost impossible to compare hurricane winds and tornado winds. In hurricanes, the pressure gradient forces act horizontally and on the scales of tens of miles. In tornadoes, the pressure gradient forces act horizontally and vertically and on the scales of only a couple of miles at most.

 

Thus, the energy density is much greater in tornadoes. The stresses placed on structures, and the debris loading due to structural failure, is much greater in tornadoes. The frictional effect, meanwhile, is much less significant in tornadoes.

 

Even though Haiyan came in nearly at peak strength, the friction from all the trees and hills in the region almost certainly means places like Tacloban and Guiuan did not receive legitimate Cat 5 conditions.

 

Who is saying Tacloban and Guiuan didn't receive Cat 5 conditions?

[Scott747]

Yeah that's a bit puzzling to say Guiuan didn't see cat 5 conditions.

 

If you want to see more legit cat 5 wind damage look at the images coming from  Manicani Island.

[eyewall]

Yeah I would say Guiuan saw Cat 5 conditions but whether or not they hit near that 190 sustained is tough to call. Josh said he observed Cat 4 conditions in Tacloban (likely in the 140 range where debarking typically begins). Frictional effects likely did slow the winds a little, even in the absolutely hardest hit areas, but 170-180 sustained could have briefly occurred in places like Guiuan.

[Stebo]

Yeah I would say Guiuan saw Cat 5 conditions but whether or not they hit near that 190 sustained is tough to call. Josh said he observed Cat 4 conditions in Tacloban (likely in the 140 range where debarking typically begins). Frictional effects likely did slow the winds a little, even in the absolutely hardest hit areas, but 170-180 sustained could have briefly occurred in places like Guiuan.

 

Agreed, the few pictures we have seen from Guiuan certainly point to them receiving Cat 5 winds

[vortex95]

I saw this posted on another forum about Haiyan:

"170 kts was the highest wind speed ever given to a typhoon by the JTWC.  As the highest value in the
modern historical record, this has generated some controversy."

I thought the same thing when I saw 170 kt on the JTWC advisory.  I couldn't recall anything higher
than 160 kt in an operational JTWC advisory the last 20 years.  Keep in mind this 170 kt based solely
on satellite estimates.

I think the day before landfall when the eye of Haiyan just missed the island nation of Palau, it could have
been stronger.  Why?  The eye was about half the size it was the day it made landfall.  It went through
an eyewall replacement cycle and the eye increased in diameter.  That's a biggie.  It's not about absolute
central pressure for the really extreme winds, it's about pressure gradient, and the smaller the
eye (pinhole eye we have heard many times), the lower the pressure and more intense sustained winds
in the inner core region.  Two TCs can have the same exact central pressure, but if one does not have a
tight and compact inner core/small eye, the winds can be much weaker, 30-40 kt difference in
max sustained winds in some cases.

Here is the Haiyan IR loop the day before landfall.
http://home.comcast.net/~trwplusa/haiyanloop1.gif

And here it is the day of landfall, notice a difference in the eye size?
http://home.comcast.net/~trwplusa/haiyanloop2.gif

The CDO is more symmetric and larger the day of landfall, but the eye diameter is also larger.
The overall power of the storm may be the same or stronger with the larger eye, but again,
absolute extreme winds I think are more dependent on the tightness of the inner core than
overall power.  Many ET storms have the power of Cat 3 hurricanes, but their max sustained
winds are not as high as a Cat 3 hurricane b/c the wind field is much more spread out.

Of note, trochoidal oscillations are evident with the eye in the first loop the day before landfall.
The pinhole eye of HU Wilma in Oct 2005 did the same thing when it peaked in (Atlantic) record
intensity for central pressure.  Soon after, an EWRC occurred.  Two days later you had a much
larger eye with the pressure up 47 mb and a decrease of 35 kt for max sustained winds.  VIS
image comparison here:

http://home.comcast.net/~trwplusa/wilmaeyecompare.GIF

Granted, the eye diameter increase in Haiyan was not nearly as dramatic, but it does lend
credence that a decent rise of pressure and decrease of max sustained winds does
occur after an EWRC.  I apologize if I am stating the obvious here, but sometime we can
overlook the obvious amidst intense speculation and thought!

So the question is, would a more symmetric, wider, and colder cloud top CDO compensate
and give winds as strong or stronger than a CDO a bit less organized but with an eye half
the size?  Without in-situ data, there no way to really tell.  However, as I pointed out above,
an eye diameter size could be more of a factor.

More factors -- vertical storm structure and efficiency of downward transport of momentum in the
boundary layer can significantly impact the winds at the surface.  I realize this is more of a factor when
a TC gets out of the tropics, but even in the tropics, no two TCs or their surrounding environmental
conditions are exactly alike.  This is one reason why Dvorak estimates is not always accurate
as to how intense the winds are in a TC.  In recent years with GPS dropsondes and the SMFR, we have
found impressive IR satellite appearance and T numbers do not always equate to expected Dvorak
estimates of surface winds.

This may sound like splitting hairs, but when it comes to the absolute extremes (i.e. world records),
details like this are very important.

[apm]

Yeah that's a bit puzzling to say Guiuan didn't see cat 5 conditions.

 

If you want to see more legit cat 5 wind damage look at the images coming from  Manicani Island.

 

Link for this?

[vortmax]

It's too bad the US didn't just send a hurricane hunter to intercept (I'm sure they could've gotten clearance from the appropriate countries, but not sure about the timing for intercept). It was certainly a rare case storm that would've been worth the time & effort.

[a5ehren]

It's too bad the US didn't just send a hurricane hunter to intercept (I'm sure they could've gotten clearance from the appropriate countries, but not sure about the timing for intercept). It was certainly a rare case storm that would've been worth the time & effort.

It's not that easy. It would probably take them 3+ days just to get to the WPAC area, and that would be if they didn't have to bring any support equipment with them.

[Drz1111]

To be fair, there is minimal scientific or engineering value in getting recon readings from a typhoon.  What would be useful would be some ground truth about winds experienced, which you could use, in combination with looking at damage, to calibrate building codes back home.  But here, given the poor quality of construction, I'm not even sure that would be useful.

 

 

 

It's too bad the US didn't just send a hurricane hunter to intercept (I'm sure they could've gotten clearance from the appropriate countries, but not sure about the timing for intercept). It was certainly a rare case storm that would've been worth the time & effort.

[WNash]

Here's a link to an interesting AP photo from Tacloban, showing a stand of intact coconut palms adjacent to the ruins of the city itself.

 

http://www.apimages.com/metadata/Index/APTOPIX-Philippines-Typhoon/8762f442cdf34f0db5b2c6fddef75f47/36/0

 

I suppose these trees might have been shielded from the worst of the winds by buildings that were destroyed by the storm surge after the worst of the winds had subsided? Not sure. But it surprises me to see a significant stand of relatively intact palms had the winds been cat 5. Of course, my point is obviously TOTALLY without context, but the photo surprised me.

 

NY Times has a better version in their slideshow: http://www.nytimes.com/slideshow/2013/11/09/world/asia/20131110_PHILIPPINES_HTML.html?ref=asia#10 -- not embedding because of rights. 

[Scott747]

Link for this?

 

I saw a couple that was a part of the Central Command/AFP flyover from Saturday. There was another one that was even more destructive than this image. Admittedly it could be storm surge but they took a direct hit.

 

[aslkahuna]

Prior to Haiyan, the highest sustained wind assigned by JT was 165kt in STY Tip in 1979. Incidentally, though unlikely a gradient of 100 mb over 10-14 miles is not impossible as such a gradient has been measured on a much smaller scale.

Steve

[Diego]

Just curious as to whether there were any inhabitants who rode out the storm on Suluan Island, Calicoan Island or Homonhon Island, at the head of the Leyte Gulf, and survived. These islands are south of the Guiuan Penisula, and the eye would have passed directly over them. Suluan Island, being the most easterly of them, would have received the initial exposure. 

 

https://maps.google.com/maps?q=suluan+island&ll=10.764171,125.822296&spn=0.29276,0.445976&hnear=Suluan+Island&t=m&z=12

 

http://en.wikipedia.org/wiki/Suluan_Island

 

http://wikimapia.org/781072/Homonhon-Island

 

http://en.wikipedia.org/wiki/Calicoan_Island

[joey2002]

Suluan Island, being the most easterly of them, would have received the initial exposure.

 

It doesn't look like anyone lives there...

[patrick05]

It doesn't look like anyone lives there...

 

there is a small community on the western side of the island..

[Amped]

there is a small community on the western side of the island..

It went the way of every other settlement in the eastern Philippians in history.