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Aussie (& S-Hemisphere) Cyclone Action 2012-2013


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Latest wind report out of NAN is 09045G76KT and the pressure is steady at 968 mb, suggesting 1) the center is passing just to the N and 2) NAN is perhaps just outside the inner core.

This would seem to be supported by the IR and visible imagery, although it's hard to tell, as the resolution is fairly low.

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Spectacular MW shot showing the cyclone's core scraping the coastline of Fiji's main island. Note the intensity estimate has increased to a whopping 125 kt. It's interesting, given that the IR presentation has actually degraded a bit in the past few hours.

Given this and the IR imagery, it looks like the inner core did pass over NAN-- in which case, I don't understand why the obs weren't a little heartier. In the last hour, they've had 60 kt (10-min), their highest sustained wind yet-- so that's at least a hurricane by our 1-min standard. The peak gust (earlier) was 90 kt.

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Latest JTWC package shows that the center passed over the W portion of Fiji's main island, with the left (stronger) eyewall passing right over Nadi International Airport (NAN). The cyclone's current estimated intensity is 115 kt-- however, the text discussion indicates it got as high as 125 kt between this package and the previous one-- that is, when the center was coming ashore. The JTWC's 06Z position (17.9S 177.3E) suggests the center passed within ~5 mi of NAN.

Given this, I remain mega-puzzled Re: the NAN data:

  • Lowest pressure: 968 mb
  • Max sustained (10-min) wind: 60 kt
  • Max gust: 90 kt

I don't get it. I'm not naive enough to have expected NAN to measure 100-kt winds-- but I would think they'd at least have sampled some 80-kt winds. Did the highest winds slip between hourly obs? Or was the offshore flow hitting friction?

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Final image today: a MW shot showing the eye over some offshore islands. Pretty cool. Residents on those islands reported calm conditions for about a half hour:

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For sure. But I expect more in the eyewall of a Cat 4.

That microwave presentation of Evan leaves a little bit to be desired. I'm certainly not sold on the 115 knot intensity, as it appears that there might have been a developing double wind maxima (note the dry moat wrapping 50% around the core in the microwave shot you posted). Satellite intensity estimates have a difficult time when ERC are in progress, and thats what appears to have been the case as Evan made landfall.

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That microwave presentation of Evan leaves a little bit to be desired. I'm certainly not sold on the 115 knot intensity, as it appears that there might have been a developing double wind maxima (note the dry moat wrapping 50% around the core in the microwave shot you posted). Satellite intensity estimates have a difficult time when ERC are in progress, and thats what appears to have been the case as Evan made landfall.

Interesting-- and agreed. We saw this with that typhoon in Okinawa earlier this year-- that crazy one with 3 or 4 concentric eyewalls. The satellite estimates were Cat 4 and yet, if I remember correctly, the highest measured winds from the core were like 40 or 50 kt. lolz

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Re: the winds in NAN...

Here's a super-zoomed-in look at that 0528Z MW shot, which was taken as the eyewall was passing close to NAN, and close to the time of their max wind (60 kt from the NNE at 0600Z).

This is actually inspired by a similar diagram I saw on a confidential mail list-- I can't share stuff from the mail list, but I thought the diagram was helpful, so I made a similar one. The meteorologist who made the diagram suggested that NAN was on the outer edge of the eyewall, and that stronger winds would have been a little W of there.

He and others have also pointed out that the convective signature was much stronger on the cyclone's right (W) side-- and so the highest winds were probably there, even though the left side is usually the stronger side in the S Hemisphere:

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So... Cyclone Evan's wicked rampage across the SPAC islands is over. It's now heading poleward and slowly unraveling over cooler waters and shear. (It'll be extratropical, 25-kt junk if and when the remnants reach NZ in a few days.)

Historically, this will go down as an important cyclone for this region-- perhaps the worst in modern times for Nadi's warning zone. The weird track, which entailed a wide loop, was like a game of Connect the Dots-- with the "dots" being Samoa, Wallis and Futuna, and Fiji-- all of which were directly and heavily impacted.

I couldn't find a nice graphic showing the complete track up to now, but this gives you a rough idea of the cyclone's history up until the Fiji strike yesterday:

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I pretty-much talked to myself during Cyclone Evan's entire lifecycle. I guess this region (SPAC area E of Oz) just isn't too interesting to anyone. But I at least expected a couple of the faithful tropical nerynerdz to join in. :(

I was following it, but it's been a bad week for me pain wise due to rapidly changing weather and arthritis. Also, I personally am not sure it was a Cat 3 let alone a 4 just didn't have the look.

Steve

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I was following it, but it's been a bad week for me pain wise due to rapidly changing weather and arthritis. Also, I personally am not sure it was a Cat 3 let alone a 4 just didn't have the look.

Steve

Steve! :)

There you are. Sorry to hear you've been in pain-- I hope it goes away as the wx stabilizes.

Nice to see you posting in this here thread. Are you saying you doubt it was a Cat 4? If so, I wonder as well. The NAN wind data aside, the station's lowest pressure was 968 mb, and I don't think it was more than ~15 mi from the center of the eye. I guess it's possible that the gradient was 2 mb/mi, so that the center had a pressure in the high 930s, but I dunno...

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