An extraordinary Cat 5 in Australian waters

By: Dr. Jeff Masters , 4:14 PM GMT on March 28, 2006

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We've got a truly exceptional Category 5 tropical cyclone in the waters off of the Western Australia coast to discuss, so the continuation of my blog on whether the global number of Category 4 and 5 hurricanes are increasing will have to wait. Tropical Cyclone Glenda is a Category 5 storm on the Saffir-Simpson scale, with maximum sustained winds of 160 mph and a central pressure estimated at 898 mb by the U.S. Navy (910 mb by the Australian Bureau of Meteorology). A central pressure of 898 mb is the lowest pressure ever estimated for a Southern Hemisphere cyclone, at least that I could find record of. Reliable records go back to the 1980s. The lowest pressure ever estimated for a Southern Hemisphere cyclone was 900 mb, for Inigo of 2003 and Gwenda of 1998. Both were Category 4 cyclones on the Saffir-Simpson scale, and hit Western Australia in a location near where Glenda is expected to strike on Thursday. The lowest pressure measured at the surface in a Southern Hemisphere cyclone was 905 mb at North Rankin A gas platform during Cyclone Orson on 22-23 April 1989. Orson had 160 mph maximum sustatined winds at the time, making it a Category 5 storm.


Figure 1. Tropical Cyclone Glenda is moving southwest, parallel to the Australian coast. This visible light image courtesy of the U.S. Navy.

Two weeks after suffering an estimated $1 billion in damage from Cyclone Larry, Australia must brace for another strike from a major hurricane. The region of Western Australia likely to be threatened by Glenda is not heavily populated, but is home to many important mining, oil, and gas operations. Over 1,500 people were eveacuated earlier this year when Tropical Cyclone Clare battered the area with 70 mph winds. Oil and gas operations are already shutting down as Australia battens down again. Glenda is in a very favorable environment for continued intensification, with water temperatures averaging 30 C (86F) underneath, and very light wind shear. It is possible that later today Glenda will reach the highest winds ever recorded in the Southern Hemisphere, equalling the record of 150 knots (172 mph) estimated for Cyclone Daryl/Agnielle in November 1995. Increasing wind shear on Wednesday should act to weaken Glenda, but she is still expected to be a formidable Category 3 or higher storm at landfall (Category 5 on the Australian intensity scale, which goes by wind gust). Glenda is the sixth tropical cyclone this season for the Western Australia area. On average, five of these storms form during the season, which runs November through April.

Jeff Masters

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132. rwdobson
5:03 PM GMT on March 29, 2006
buster: Go ahead prove me wrong!!!!

It's your new proposal, buster. therefore, the burden of proof is on the affirmative side, i.e. you.

we don't have to prove you wrong, you have to prove you are right.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
131. ForecasterColby
11:34 AM GMT on March 29, 2006
Yeah, the eye just isn't quite getting up. Indistinct on recent IR.
130. lemmo
8:30 AM GMT on March 29, 2006
Rainfall here

Latest IR, showing eye still clearly visible but deepest convection off-centred.
129. Merovingian
6:55 AM GMT on March 29, 2006
This is really something to watch!
128. Levi32
5:56 AM GMT on March 29, 2006
Yes Michael I noticed that. That is nerve racking to think about. I hope that doesn't happen.

Well I have to head off to bed so goodnight everyone. We will see how Glenda is doing in the morning. Tomorrow will be a very exciting day.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
126. Levi32
5:47 AM GMT on March 29, 2006
Here is a great forecast model page for Glenda. Intensity forecasts and tracks are available.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
125. Levi32
5:40 AM GMT on March 29, 2006
There we go.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
124. Levi32
5:39 AM GMT on March 29, 2006
Member Since: November 24, 2005 Posts: 635 Comments: 26700
123. Levi32
5:38 AM GMT on March 29, 2006
am I doing something wrong?
Member Since: November 24, 2005 Posts: 635 Comments: 26700
122. Levi32
5:38 AM GMT on March 29, 2006
darn, lets try that again:
img
src=http://www.nrlmry.navy.mil/htdocs_dyn/tc_pages/thumbs/SHEM/20S.GLENDA/pacific/southern_hemisphere/vis/geo/vis/geo/1km_zoom/20060329.0430.gms6.x.vis1km_high.20SGLENDA.120kts-922mb-171S-1194E.100pc.jpg>
Member Since: November 24, 2005 Posts: 635 Comments: 26700
121. Levi32
5:37 AM GMT on March 29, 2006
Looking better on visible:
img
src="http://www.nrlmry.navy.mil/htdocs_dyn/tc_page/southern_hemisphere/vis/geo/vis/geo/1km_zoom/20060329.0430.gms6.x.vis1km_high.20SGLENDA.120kts-922mb-171S-1194E.100pc.jpg">
Member Since: November 24, 2005 Posts: 635 Comments: 26700
120. Levi32
5:35 AM GMT on March 29, 2006
Agreed there Hurricane, the shear didn't affect her very much, but now there is less shear, so she has more room to strengthen. That is the dangerous part for Australia.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
119. HurricaneMyles
5:31 AM GMT on March 29, 2006
Agreed, Levi, that on IR the convection on the right side of Glenda appeared more sheared and compressed then she appears now.

If you look at this loop you can see she still had the 'buzzsaw' look of a very powerful hurricane, and shear didnt look to be a problem.
Member Since: January 12, 2006 Posts: 5 Comments: 827
118. Levi32
5:30 AM GMT on March 29, 2006
Hmmm, she may be ready to bomb again. Here is an IR floater loop. You will see what I mean about the shear. Look at her grow...
Member Since: November 24, 2005 Posts: 635 Comments: 26700
117. HurricaneMyles
5:27 AM GMT on March 29, 2006
Oh my! Glenda's eye has shown up clearly now on IR.

Member Since: January 12, 2006 Posts: 5 Comments: 827
116. Levi32
5:24 AM GMT on March 29, 2006
Well, maybe the convection on the SW side is a little weak, but look at the eye, if you look at a loop since this morning, you will see the eye is much more in the center of the whole thing. That means less shear than before. Also she is almost twice as big as when she formed.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
114. Levi32
5:17 AM GMT on March 29, 2006
Actually HurricaneMyles, have you noticed that the eye is more in the center of the convection since this morning? Before, easterly wind shear had pushed the bulk of the convection west of the center. Now it is much more symetrical.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
113. Inyo
5:15 AM GMT on March 29, 2006
they still do cloud seeding in the mountains of California, and it appears that it does increase precipitation in these areas. However, it is probably at the expense of areas downstream. Unless you can increase the evaporation from the ocean (as with global warming) you can't increase total global precip.

however, the idea that cloud seeding weakens hurricanes is a tenuous one at best, and to me seems counterintuitive. It seems to me that increased condensation on nucleii would release heat and if anything, intensify the hurricane. perhaps finding a way to remove nucleii would reduce its strength but could also lead to severe droughts.
Member Since: September 3, 2002 Posts: 42 Comments: 905
112. HurricaneMyles
5:14 AM GMT on March 29, 2006
Agreed Levi32. Windshear has increased slightly since Glenda bombed to 898mb. We'll see if that inhibits her from getting close to that intensity again.
Member Since: January 12, 2006 Posts: 5 Comments: 827
111. Levi32
5:11 AM GMT on March 29, 2006
I think that another strengthening to cat 5 is possible. The whole thing is controled by the wind shear. If the wind shear stays low all the way until landfall, then we may just have another storm close to Katrina's standards.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
110. Skyepony (Mod)
5:07 AM GMT on March 29, 2006
Wave model for the area. There's a Java loop on the upper right. You can see the waves drop from aproaching 35' down to around 25' with the eye wall replacement.
Member Since: August 10, 2005 Posts: 226 Comments: 39438
109. jeffB
5:03 AM GMT on March 29, 2006
OK here is the proof. What temperature are you most comfortable in? 68 degrees to 72 degrees is the answer.

Here's the proof. What are you most comfortable in, air or water? Air is the answer. So, if we DRY UP the entire ocean, the fish should still be perfectly happy.

I swear, it's getting so that the best part of this blog is seeing what inanity 'buster will come up with next.
Member Since: July 8, 2005 Posts: 0 Comments: 42
108. HurricaneMyles
4:56 AM GMT on March 29, 2006
Hmm...try again.

Member Since: January 12, 2006 Posts: 5 Comments: 827
107. HurricaneMyles
4:55 AM GMT on March 29, 2006
Member Since: January 12, 2006 Posts: 5 Comments: 827
106. HurricaneMyles
4:53 AM GMT on March 29, 2006
Oh boy! Eye becoming starting to clear out on visable Sat. ERC is coming to an end!
Member Since: January 12, 2006 Posts: 5 Comments: 827
105. chrisJ2
4:40 AM GMT on March 29, 2006
104. DAVIDKRZW
4:40 AM GMT on March 29, 2006
: HurricaneMyles we need a storm to talk about over her how mean more weeks do we have to go in tell the start of hurricane year 2006 i think we are going to see a lot of pinhole eye for are hurricane year 2006 like they are seeing over there and is it odd to see a lot of the pinhole eye over there i think it is the 3rd pinhole eye for them this year
103. TheSnowman
4:38 AM GMT on March 29, 2006
Well From reading Jeff's Blog, This is what I get..... for some Fast Statistics

- Very Rare Category 5 on SS Scale not Australian Scale
- This is occuring At the Very End of the Season
- Possibly Smallest Eye ever in the Southern Hem.
- Lowest Pressure Ever in Southern Hem.
102. snowboy
4:35 AM GMT on March 29, 2006
that is still one nasty hurricane, hope they've got things tied down "Down Under"
Member Since: September 21, 2005 Posts: 10 Comments: 2555
101. HurricaneMyles
4:35 AM GMT on March 29, 2006
David,

The reason the winds are not higher is because this is not in the Atlantic. Other ocean basins have a much lower natural sea pressure, so it requires a storm to get much lower pressures then we see in the Atlantic to get winds that are as strong. I hope that explains it for you.

I would guess the eye was <5 miles across. It was probably closer to 2-4 miles across. It was very close to as small as Wilma was. Its very possible, in my view, that Glenda's eye became as small as Wilma's during her intesification.
Member Since: January 12, 2006 Posts: 5 Comments: 827
99. HurricaneMyles
4:29 AM GMT on March 29, 2006
Cloud seeding has about as much proof as the tunnels, as in nothing but speculation.

I too smell a Katrina, and it kinda scares me. Katrina strengthen right out of her ERC into the Cat 5 beast she became. It would be the most rediculous thing to see a single storm to develope both a pinhole eye with 160 mph, and then an annular type eye with 160 mph...just crazy.
Member Since: January 12, 2006 Posts: 5 Comments: 827
98. DAVIDKRZW
4:29 AM GMT on March 29, 2006
i got a ? if this storm had 898mb and 160mph winds and i do not think a 898mb can have 160 so try more like 175mph or 180mph for 898mb

did the R storm have a 895mb and 180mph winds

so why dos this storm we are talking about have 160mph winds and a 898mb?

is any one geting me her
97. TheSnowman
4:27 AM GMT on March 29, 2006
Does Anyone know how small the eye was when it was the Smallest....
95. ForecasterColby
4:22 AM GMT on March 29, 2006
ERC is nearly complete, she'll have 1 more diurnal max as she approaches landfall...I smell a Katrina.

93. HurricaneMyles
3:57 AM GMT on March 29, 2006
It's estimated by JTWC that Glenda is 922mb and 120 kt winds.
Member Since: January 12, 2006 Posts: 5 Comments: 827
92. louastu
3:52 AM GMT on March 29, 2006
How strong is Glenda right now?
91. HurricaneMyles
3:50 AM GMT on March 29, 2006
Ahh, I'm not sure what that had to do w/anything, but yeah...

Anyways, returning to Glenda -

Australia will be very lucky if Glenda does not complete this ERC before landfall. If it can form a well defined eye before coming ashore then thier is always the possibility of restregthening right before and during landfall.
Member Since: January 12, 2006 Posts: 5 Comments: 827
87. HurricaneMyles
3:39 AM GMT on March 29, 2006
Nuclear winter is not possible to survive. Enough bombs would spread radiation throughout the entire planet, killing almost everything, expecially large, complex creature like humans.

The Earth is not going to become like Venus anytime soon, as the major reason it is so hot is that it is so much closer to the Sun then the Earth.
Member Since: January 12, 2006 Posts: 5 Comments: 827
84. WeatherWizard
3:33 AM GMT on March 29, 2006
Cyclonenutjob, don't tell me what I can or can't tell you. {{sticking out tongue}} It's hard not to read your crap when you do nothing but spam this place with it. And don't worry about the big bad wolf blowing my house down. Nobody, including you, especialy you, and your damn tunnels are going to stop it if it happens.

Man, if only we could use the tunnel to get rid of you.....

How long have you been spouting off about this crap? Who exactly is it here that you're trying to convince? And how exactly is convincing that person going to change ANYTHING??

Get a freaking clue already. All this time you've WASTED blowing off about tunnels and you haven't changed a damn thing. What a waste.

Give it a rest.
83. Inyo
3:29 AM GMT on March 29, 2006
as i biologist, i can tell you that 'most' sea life does NOT prefer temperatures of 68-72, and it would probably kill coral reefs to cool the water to that temperature all summer... coral reefs reduce the impact of storm surge and waves.

There are different types of sea life associated with different types of water. When El Nino occurs in southern California, different fish are found in the water than when La Nina or neutral conditions occur. Fish and some other forms of aquatic organisms can follow changes in temperature caused by climate or season, to stay in their optimal area. However, if an 'island' of cold water is created surrounded by warm water, the fish there will leave and the cold-loving fish from the north won't know to cross the 80 degree water to get there.
Member Since: September 3, 2002 Posts: 42 Comments: 905
82. HurricaneMyles
3:29 AM GMT on March 29, 2006
You mean the people who said your idea could only possibly work for the gulf stream off the coast of Miami?
Member Since: January 12, 2006 Posts: 5 Comments: 827

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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