Glenda takes aim at Australia

By: Dr. Jeff Masters , 2:25 PM GMT on March 29, 2006

Tropical Cyclone Glenda has weakened to Category 3 storm on the Saffir-Simpson scale, with maximum sustained winds of 120 mph and a central pressure estimated at 920 mb by the Australian Bureau of Meteorology. While no longer one of the Southern Hemisphere's most intense tropical cyclones on record, Glenda is still a formidable storm likely to inflict heavy damage to the mining, oil, and gas industries along the Western Australian coast. The storm is expected to make landfall as a major Category 3 storm on the Saffir-Simpson scale Thursday. Fortunately, the region is sparsely populated, and significant upper-level winds associated with the jet stream should act to weaken Glenda just before landfall. Still, a 8 - 12 foot storm surge near and to the left of where the eye makes landfall can be expected. This was the approximate storm surge seen from Cyclone Vance in March 1999, a storm similar in strength and landfall location to Glenda. An impressive satellite animation of Glenda is available from the University of Wisconsin.


Figure 1. Tropical Cyclone Glenda at 6:30 GMT March 29 2006, moving southwest parallel to the Australian coast. This visible light image courtesy of the U.S. Navy.

Was Glenda the strongest tropical cyclone ever in the Southern Hemisphere?
The U.S. Navy estimated a central pressure of 898 mb yesterday for Glenda, which is the second lowest pressure I could find record of for the Southern Hemisphere. However, I doubt that this pressure will be considered official, since the Australian Bureau of Meteorology estimated a much higher minimum pressure of 910 mb. Unfortunately, the Joint Typhoon Warning Center does not make official pressure estimates. The record lowest pressure in the Southern Hemisphere is 879 mb, held by Cyclone Zoe of 2002, a Category 5 storm that affected several small islands in the Solomon chain. Reliable records of Southern Hemisphere cyclones only go back to the 1980s, so it is likely that there were other storms with lower pressures than Glenda in the Southern Hemisphere during the past century. 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 maximum sustatined winds at the time, making it a Category 5 storm.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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138. cgableshurrycanegal
11:58 PM GMT on March 30, 2006
Having friends in AU and NZ thx to the Internet I now REALLY pay attention to the cyclones that hit the area. Fortunately everyone I know seems to be to the south of the parts of AU that get blasted the most.
We can certainly empathize with them, those of us within the hurricane strike zone...
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137. Skyepony
3:51 PM GMT on March 30, 2006
Jeff's got a new blog is up. & my internet connection is working again:)(at least for now)
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136. HurricaneMyles
4:24 AM GMT on March 30, 2006
Her eye wall is impacting the islands and cape near the coast right now. The eye will probably be inland within a couple hours.
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135. louastu
4:21 AM GMT on March 30, 2006
How long before she makes landfall?
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134. ForecasterColby
4:10 AM GMT on March 30, 2006
Cyclone, you watched Category 7, didn't you?

Glenda is looking pretty good, but too close to landfall - she'll hit hard, but not like she would have.
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133. theboldman
3:51 AM GMT on March 30, 2006
just having some fun with cyclone im not bashing anybody

huh cyclone>????
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132. louastu
3:50 AM GMT on March 30, 2006
theboldman,

Why is it that you insist on causing problems? Your remarks have been very childish. To tell you the truth, in just three posts of yours I can already see that you have some disturbing desire to make others feel like idiots.

I don't understand why it is you feel like doing this, but I can tell you that it is not cool, and is in fact, completely unacceptable.
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131. theboldman
3:28 AM GMT on March 30, 2006
lol cyclone

amazing thought that was all you could think of

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130. Levi32
3:21 AM GMT on March 30, 2006
I got to go for a while be back as soon as I can.
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129. Levi32
3:16 AM GMT on March 30, 2006
I found out how to get better visible images! HurricaneMyles, on your site, go to the visible image. Then, on the top, click prev.(short for previous). A list of previous visible images will come up. In the tital of each image is the name of the satellite that takes the image. There are some GMS-6 images scattered around in there. GMS-6 has much better resolution.
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128. HurricaneMyles
3:12 AM GMT on March 30, 2006
Sure, it's a different version of the NAVY site.

Link
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127. Levi32
3:12 AM GMT on March 30, 2006
HurricaneMyles nvm, I got the site.
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126. Levi32
3:10 AM GMT on March 30, 2006
HurricaneMyles, you are getting that sat shot off a different site then my picture. Could you direct me to that site?
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125. HurricaneMyles
3:00 AM GMT on March 30, 2006
I wish we could see some better visable images, too. However you can see a faint eye on METEO right now.

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124. louastu
3:00 AM GMT on March 30, 2006
As long as the air is not dry, then I would say that at the very least it wouldn't hurt the storm.
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122. Levi32
2:59 AM GMT on March 30, 2006
Eye is appearing on visible satellite again. And just look at it reorganize on radar.

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120. Levi32
2:39 AM GMT on March 30, 2006
I wonder why there are no MTSAT visible images available for Glenda. There are only METEO-5 images. METEO-5 has very low resolution, so the visible images don't give us very much information since it is hard to see any detail.
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119. louastu
2:38 AM GMT on March 30, 2006
theboldman,

At this time there are no problems on this site. Please don't start any.
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117. Levi32
2:35 AM GMT on March 30, 2006
Glenda's eyewall is nearly closed on radar
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116. theboldman
2:35 AM GMT on March 30, 2006
cyclone the tunnels will fix this ill bet lol

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115. HurricaneMyles
2:33 AM GMT on March 30, 2006
Well, I cant really explain why the eye shrinks. Most likely because it cant support itself on land so it shrinks to continue pulling condensation from the ocean.

It strengthens because thats what happens when eyes shrink. It has to do with your principles, you should know. As you decrease the area a fluid travels through the fliud travels more quickly through that area.
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114. DAVIDKRZW
2:33 AM GMT on March 30, 2006
would a hurricane like 150 sea temps
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113. Califonia
2:33 AM GMT on March 30, 2006
Posted By: louastu at 12:01 AM GMT on March 30, 2006.

The reason (the eclipse) could have an effect on the height of the storm surge is due to the combined effects of gravity from the Sun, and the Moon. This could cause a high tide to be a little higher than normal, and if a hurricane hits at that exact moment then it is possible that the storm surge would be larger.


When a hurricane makes landfall at the time the tide is highest, it makes the storm surge that much worse. Conversely, a low tide will reduce the damage of the storm surge.

An especially high tide will happen during the new moon and the full moon. This is called a spring tide (has nothing to do with the season). The low tide will be exceptionally low as well.

Since a solar eclipse happens at new moon, and a lunar eclipse happens at full moon, both will cause unusually high and low tides, and hence the potential for extra damage (or extra-low damage) depending on the timing of the landfall.

The fact that a new or full moon happens to be an eclipse will not significantly increase the tidal effect - it should be about the same as any other new or full moon.
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111. HurricaneMyles
2:29 AM GMT on March 30, 2006
What are you referring to when you ask 'how'? How does the eye shrink? Or how does is strengthen? I'm not sure where you're coming from.
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110. DAVIDKRZW
2:23 AM GMT on March 30, 2006
by hot sea water can help
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108. HurricaneMyles
2:16 AM GMT on March 30, 2006
Buster,

Some hurricane strengthen prior to landfall, ala Andrew 1992, because land causes the eye to contract and winds increase because of a smaller eye. If has nothing to do with how hot the land is or anything like that.
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106. HurricaneMyles
1:53 AM GMT on March 30, 2006
Glenda is moving into a slightly move favorable environment now. Shear has decreased from 20-25kts to 10-15kts which Glenda appears to be taking advantage of. The only thing land will do to the cyclone is possibly cause the eye to shrink as it comes ashore.
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105. Inyo
1:48 AM GMT on March 30, 2006
um, land masses make hurricanes weaker, not stronger.
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102. louastu
12:24 AM GMT on March 30, 2006
Well, the Pacer game is on. I guess I will bbl.
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101. Levi32
12:17 AM GMT on March 30, 2006
I have to go. I will be back in a few hours.
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100. Levi32
12:14 AM GMT on March 30, 2006
I also noticed that there are only METEO-5 sat images on NRL. There should be MTSAT images too. They were there yesterday.
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99. Levi32
12:13 AM GMT on March 30, 2006
Why do you suppose there are no visible images yet of Glenda on the NRL site? The full disk image shows the sun on Glenda 2 hours ago.
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98. louastu
12:12 AM GMT on March 30, 2006
The world would probably start to panic. As far as the effect on a hurricane, I don't know.
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96. Levi32
12:09 AM GMT on March 30, 2006
Louastu, The sun's gravity is always the same, and if the moon came directly in front of the sun over a tropical cyclone, then it would be no different than if the moon was in another place in the sky.
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95. Levi32
12:07 AM GMT on March 30, 2006
Louastu how could a solar eclipse possibly interact with storm surge height? I don't think eclipses have any effect on hurricanes whatsoever.
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94. louastu
12:05 AM GMT on March 30, 2006
The reason it could have an effect on the height of the storm surge is due to the combined effects of gravity from the Sun, and the Moon. This could cause a high tide to be a little higher than normal, and if a hurricane hits at that exact moment then it is possible that the storm surge would be larger.
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93. Levi32
12:05 AM GMT on March 30, 2006
Looks like the SE side of the eyewall is coming back. I hope she doesn't bomb now.
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92. Levi32
12:03 AM GMT on March 30, 2006
Aha! Glenda's eye is trying to come back together. Here is microwave and radar images:



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91. louastu
12:00 AM GMT on March 30, 2006
I doubt it. I would say that the only likely effect would be on the storm surge height.
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90. Levi32
11:59 PM GMT on March 29, 2006
Yeah I suppose you are right Michael. Boy we sure smashed a ton of records to the bottom of the closet this last season.
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89. HurricaneMyles
11:55 PM GMT on March 29, 2006
I dont think solar ecplipses have any effect on hurricanes, expecially since the solar ecplipse is a regional thing and only a small part of the world actually sees the sun blocked from view.

I wouldnt understand how it could effect a hurricane anyways. Do you have another idea or something buster?
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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