APOD: Hurricane Harvey Strengthens (2017 Aug 26)

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APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby APOD Robot » Sat Aug 26, 2017 4:09 am

Image Hurricane Harvey Strengthens

Explanation: A large and dangerous hurricane has developed in the Gulf of Mexico. The featured time-lapse video shows Hurricane Harvey growing to Category 4 strength over the past few days, as captured by NASA and NOAA's GOES-East satellite. Starting as a slight dip in air pressure, hurricanes swell into expansive spiraling storm systems, complete with high winds and driving rain. Hurricanes are powered by evaporating ocean water, and so typically gain strength over warm water and lose strength over land. Much remains unknown about hurricanes and cyclones, including details of how they are formed and the exact path they will take. Hurricane Harvey, accompanied by a dangerous storm surge, is expected to make landfall sometime today in Texas.

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby heehaw » Sat Aug 26, 2017 10:02 am

When I was a boy (I was born in 1940) people knew about a hurricane when it arrived. No time for preparation at all!

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby neufer » Sat Aug 26, 2017 12:12 pm

heehaw wrote:
When I was a boy (I was born in 1940) people knew about a hurricane when it arrived. No time for preparation at all!
https://en.wikipedia.org/wiki/History_o ... one_naming wrote:
Click to play embedded YouTube video.
<<Credit for the first usage of personal names for weather is generally given to the Queensland Government Meteorologist Clement Wragge, who named named tropical cyclones and anticyclones between 1887–1907. Wragge used names drawn from the letters of the Greek alphabet, Greek and Roman mythology and female names, to describe weather systems over Australia, New Zealand and the Antarctic. After the new Australian government had failed to create a federal weather bureau and appoint him director, Wragge started naming cyclones after political figures. Wragge's naming was also mentioned within Sir Napier Shaw’s “Manual of Meteorology” which likened it to a "child naming waves".

After reading about Clement Wragge, George Stewart was inspired to write a novel, "Storm", about a storm affecting California which was named Maria. During 1944, United States Army Air Forces forecasters (USAAF) at the newly established Saipan weather center, started to informally name typhoons after their wives and girlfriends. However, they were not able to persuade the United States Weather Bureau (USWB) to start naming Atlantic hurricanes, as the Weather Bureau wanted to be seen as a serious enterprise, and thus felt that it was "not appropriate" to name tropical cyclones while warning the United States public. They also felt that using women's names was frivolous and that using the names in official communications would have made them look silly. During 1947 the Air Force Hurricane Office in Miami started using the Joint Army/Navy Phonetic Alphabet to name significant tropical cyclones in the North Atlantic Ocean.

During August and September 1950, three tropical cyclones (Hurricanes Baker, Dog and Easy) occurred simultaneously and impacted the United States during August and September 1950, which led to confusion within the media and the public. As a result, during the next tropical cyclone (Fox), Grady Norton decided to start using the names in public statements and in the seasonal summary. This practice continued throughout the season, until the system was made official before the start of the next season. During 1952, a new International Phonetic Alphabet was introduced, as the old phonetic alphabet was seen as too Anglocentric. This led to some confusion with what names were being used, as some observers referred to Hurricane Charlie as "Cocoa." Ahead of the following season no agreement could be reached over which phonetic alphabet to use, before it was decided to start using a list of female names to name tropical cyclones. The same names were reused during 1954 with only one change: Gilda for Gail. However, as Hurricanes Carol, Edna, and Hazel affected the populated Northeastern United States, controversy raged with several protests over the use of women’s names as it was felt to be ungentlemanly or insulting to womanhood, or both. Letters were subsequently received that overwhelmingly supported the practise, with forecasters claiming that 99% of correspondence received in the Miami Weather Bureau supported the use of women’s names for hurricanes.>>
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Chris Peterson » Sat Aug 26, 2017 2:22 pm

heehaw wrote:When I was a boy (I was born in 1940) people knew about a hurricane when it arrived. No time for preparation at all!

Hurricanes have been forecast since at least the late 1800s. Computers and satellites have made those forecasts much more accurate, of course, reducing the possibility of another Galveston (1900), where meteorologists were aware of the storm days in advance, but made many errors in tracking it and providing warning.
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Tilt » Sat Aug 26, 2017 2:43 pm

Dennis Chesters Strikes from Afar —

https://goes.gsfc.nasa.gov/

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Tilt » Sat Aug 26, 2017 2:50 pm


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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby neufer » Sat Aug 26, 2017 3:10 pm

Chris Peterson wrote:
heehaw wrote:
When I was a boy (I was born in 1940) people knew about a hurricane when it arrived. No time for preparation at all!

Hurricanes have been forecast since at least the late 1800s. Computers and satellites have made those forecasts much more accurate, of course, reducing the possibility of another Galveston (1900), where meteorologists were aware of the storm days in advance, but made many errors in tracking it and providing warning.

Perhaps heehaw is not being entirely honest about when he was born.

Today (thanks to satellites & computers ) people knew to evacuate for Hurricane Harvey a full 42 hours before it arrived. :!:
https://en.wikipedia.org/wiki/Hurricane ... al_history wrote:
<<A reconnaissance aircraft investigating the [open tropical wave] remnants of Harvey around 15:00 UTC on August 23 indicated that it once again acquired a well-defined center, and the NHC upgraded it to a tropical depression accordingly. The system began to slowly consolidate amid an increasingly favorable environment, attaining tropical storm intensity by 06:00 UTC on August 24. Later that morning, Harvey began to undergo rapid intensification as an eye developed and its central pressure quickly fell. By 17:00 UTC, the storm was upgraded to the third hurricane of the season. Slight entrainment of dry air slowed the intensification process, however, by the next day, Harvey was able to quickly strengthen into a major hurricane by 19:00 UTC. Further deepening occurred as the storm approached the coast of Texas, with Harvey becoming a category 4 hurricane at 23:00 UTC, based on reconnaissance aircraft data. Around 03:00 UTC on August 26, the hurricane made landfall between Port Aransas and Port O'Connor with winds of 130 mph and an atmospheric pressure of 938 mbar.>>
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Re: APwhich is better , being in a big ole ship or a tiny little betty canoe ?OD: Hurricane Harvey Strengthens (2017 Aug

Postby ta152h0 » Sat Aug 26, 2017 5:37 pm

Which is better, being in a big ole ship or a tiny caboe ? Or even inside a inflatable ball ?
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby RJN » Sat Aug 26, 2017 5:52 pm

The APOD text has been sightly changed to indicate that Hurricane Harvey made landfall late yesterday.
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Re: APwhich is better , being in a big ole ship or a tiny little betty canoe ?OD: Hurricane Harvey Strengthens (2017 Aug

Postby neufer » Sat Aug 26, 2017 8:42 pm



ta152h0 wrote:
Which is better, being in a big ole ship or a tiny caboe?

A tiny caboe
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Boomer12k » Sat Aug 26, 2017 8:51 pm

Odd. How it looks like a galaxy.... huh?

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby neufer » Sun Aug 27, 2017 11:26 am

Boomer12k wrote:
Odd. How it looks like a galaxy.... huh?

Texas is a large state.
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby bystander » Sun Aug 27, 2017 3:55 pm

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby MarkBour » Wed Aug 30, 2017 2:45 pm

Did the astronauts on the ISS ever say: "Houston you have a problem." ?

I sometimes see phrases like "Hurricane X is about to slam into the coast of Y." As Harvey demonstrated, some of the worst cases can be when Hurricane X just gently slides into the coast ... then slowly turns around (all the while dumping on the same spot).
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby bystander » Wed Aug 30, 2017 7:05 pm

TS Harvey made landfall again last night in SW Louisiana
http://www.nhc.noaa.gov/archive/2017/HA ... aphics.php
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Ann » Wed Aug 30, 2017 11:57 pm

neufer wrote:
heehaw wrote:
When I was a boy (I was born in 1940) people knew about a hurricane when it arrived. No time for preparation at all!
https://en.wikipedia.org/wiki/History_o ... one_naming wrote:
Click to play embedded YouTube video.
<<Credit for the first usage of personal names for weather is generally given to the Queensland Government Meteorologist Clement Wragge, who named named tropical cyclones and anticyclones between 1887–1907. Wragge used names drawn from the letters of the Greek alphabet, Greek and Roman mythology and female names, to describe weather systems over Australia, New Zealand and the Antarctic.
...
During 1952, a new International Phonetic Alphabet was introduced, as the old phonetic alphabet was seen as too Anglocentric. This led to some confusion with what names were being used, as some observers referred to Hurricane Charlie as "Cocoa." Ahead of the following season no agreement could be reached over which phonetic alphabet to use, before it was decided to start using a list of female names to name tropical cyclones. The same names were reused during 1954 with only one change: Gilda for Gail. However, as Hurricanes Carol, Edna, and Hazel affected the populated Northeastern United States, controversy raged with several protests over the use of women’s names as it was felt to be ungentlemanly or insulting to womanhood, or both. Letters were subsequently received that overwhelmingly supported the practise, with forecasters claiming that 99% of correspondence received in the Miami Weather Bureau supported the use of women’s names for hurricanes.>>


Right. Men named the raging fury of hurricanes after women. :evil:

I'm not nearly the feminist I once was, but this practice irked me. It's a very good thing that it has changed, of course. :ssmile:

But meteorologist Clement Wragge is not a hero in my book. :no:

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Ann » Thu Aug 31, 2017 12:00 am

neufer wrote:
Boomer12k wrote:
Odd. How it looks like a galaxy.... huh?

Texas is a large state.


Actually, many hurricanes do look a lot like (idealized) spiral galaxies.

I guess we are dealing with nature's way of (at least sometimes) using the same shapes for objects large and small.

Click to play embedded YouTube video.

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby Ann » Thu Aug 31, 2017 12:04 am

I must add that I'm really sorry about all the damage done by hurricane Harvey.

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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby neufer » Thu Aug 31, 2017 4:39 am

Ann wrote:
Right. Men named the raging fury of hurricanes after women. :evil:

I'm not nearly the feminist I once was, but this practice irked me. It's a very good thing that it has changed, of course. :ssmile:

But meteorologist Clement Wragge is not a hero in my book. :no:
https://en.wikipedia.org/wiki/Clement_Lindley_Wragge wrote:
<<Politicians to have cyclones named after them by Wragge included James Drake, Edmund Barton and Alfred Deakin. Other colourful names he used included Xerxes, Hannibal, Blasatus and Teman.>>
https://en.wikipedia.org/wiki/William_Congreve wrote:
William Congreve (24 January 1670 – 19 January 1729) was an English playwright and poet of the Restoration period. He is known for his clever, satirical dialogue and influence on the comedy of manners style of that period. He was also a minor political figure in the British Whig Party. Two of Congreve's phrases from The Mourning Bride (1697) have become famous, although sometimes misquoted or misattributed to William Shakespeare.

"Musick has charms to soothe a savage breast," which is the first line of the play, spoken by Almeria in Act I, Scene I. This is often rendered as: "Music hath charms to soothe the savage breast" or even savage beast.

"Heaven has no rage like love to hatred turned, Nor hell a fury like a woman scorned," spoken by Zara in Act III, Scene VIII, but paraphrased as "Hell hath no fury like a woman scorned".
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E'erawhere in this whorl would ye hear sich a din again?

Postby neufer » Thu Aug 31, 2017 4:51 am

Ann wrote:
neufer wrote:
Boomer12k wrote:
Odd. How it looks like a galaxy.... huh?

Texas is a large state.

Actually, many hurricanes do look a lot like (idealized) spiral galaxies.

I guess we are dealing with nature's way of (at least sometimes) using the same shapes for objects large and small.

https://en.wikipedia.org/wiki/Spiral#In_nature wrote:

<<The study of spirals in nature has a long history. Christopher Wren observed that many shells form a logarithmic spiral; Jan Swammerdam observed the common mathematical characteristics of a wide range of shells from Helix to Spirula; and Henry Nottidge Moseley described the mathematics of univalve shells. D’Arcy Wentworth Thompson's On Growth and Form gives extensive treatment to these spirals. He describes how shells are formed by rotating a closed curve around a fixed axis, the shape of the curve remains fixed but its size grows in a geometric progression. In some shell such as Nautilus and ammonites the generating curve revolves in a plane perpendicular to the axis and the shell will form a planar discoid shape. In others it follows a skew path forming a helico-spiral pattern. Thompson also studied spirals occurring in horns, teeth, claws and plants.

A model for the pattern of florets in the head of a sunflower was proposed by H Vogel. This has the form:


where n is the index number of the floret and c is a constant scaling factor, and is a form of Fermat's spiral. The angle 137.5° is the golden angle which is related to the golden ratio and gives a close packing of florets.

Spirals in plants and animals are frequently described as whorls. This is also the name given to spiral shaped fingerprints.>>
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby MarkBour » Tue Sep 05, 2017 9:57 pm

Boomer12k wrote:Odd. How it looks like a galaxy.... huh?
:---[===] *

Not only the static look is similar, but I believe the motion over time is also similar (not the same, but similar).

I think it is no coincidence; In a hurricane, you see the clouds. This is a subset of the matter that is present and it is being drawn gently inward by the low pressure in the center, all the while being dragged around by the much larger set of invisible air molecules in which it is suspended. In a spiral galaxy, you see the normal matter that is present (mostly the light-emitting matter, but also dust lanes) and it is being drawn gently inward by gravity toward the center, all the while being influenced by the larger set of dark matter in which it lies.
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby geckzilla » Wed Sep 06, 2017 1:32 am

MarkBour wrote:
Boomer12k wrote:Odd. How it looks like a galaxy.... huh?
:---[===] *

Not only the static look is similar, but I believe the motion over time is also similar (not the same, but similar).

I think it is no coincidence; In a hurricane, you see the clouds. This is a subset of the matter that is present and it is being drawn gently inward by the low pressure in the center, all the while being dragged around by the much larger set of invisible air molecules in which it is suspended. In a spiral galaxy, you see the normal matter that is present (mostly the light-emitting matter, but also dust lanes) and it is being drawn gently inward by gravity toward the center, all the while being influenced by the larger set of dark matter in which it lies.

I think the resemblance is a passing one only. If the spiral density wave model is correct, not only are the forces involved dramatically different, the particles aren't even taking similar paths. The analogy is potentially very misleading.
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby neufer » Wed Sep 06, 2017 2:16 am

geckzilla wrote:
MarkBour wrote:
Boomer12k wrote:
Odd. How it looks like a galaxy.... huh?

Not only the static look is similar, but I believe the motion over time is also similar (not the same, but similar). I think it is no coincidence; In a hurricane, you see the clouds. This is a subset of the matter that is present and it is being drawn gently inward by the low pressure in the center, all the while being dragged around by the much larger set of invisible air molecules in which it is suspended. In a spiral galaxy, you see the normal matter that is present (mostly the light-emitting matter, but also dust lanes) and it is being drawn gently inward by gravity toward the center, all the while being influenced by the larger set of dark matter in which it lies.

I think the resemblance is a passing one only. If the spiral density wave model is correct, not only are the forces involved dramatically different, the particles aren't even taking similar paths. The analogy is potentially very misleading.


This was, certainly, my initial reaction...but there is perhaps a bit of truth to the analogy; e.g., the spiral structures are relatively stationary wave structures compared with particles that are rotating faster near the center that further out.

Hurricane Irma :arrow:
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby MarkBour » Thu Sep 07, 2017 10:16 pm

geckzilla wrote:I think the resemblance is a passing one only. If the spiral density wave model is correct, not only are the forces involved dramatically different, the particles aren't even taking similar paths. The analogy is potentially very misleading.

I should have put some disclaimer on my post. I think all of the aspects I stated are easily established facts, but you're right, they would urge a conclusion (as analogies do) that the motions really are quite similar. I'll go read some more on density wave theory if I get a chance. If spiral galaxies obey that, then are you saying that typhoons do not fit it?
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Re: APOD: Hurricane Harvey Strengthens (2017 Aug 26)

Postby geckzilla » Fri Sep 08, 2017 4:20 am

MarkBour wrote:
geckzilla wrote:I think the resemblance is a passing one only. If the spiral density wave model is correct, not only are the forces involved dramatically different, the particles aren't even taking similar paths. The analogy is potentially very misleading.

I should have put some disclaimer on my post. I think all of the aspects I stated are easily established facts, but you're right, they would urge a conclusion (as analogies do) that the motions really are quite similar. I'll go read some more on density wave theory if I get a chance. If spiral galaxies obey that, then are you saying that typhoons do not fit it?

At my current state of knowledge, no, I don't think typhoons fit at all, or only in a very limited sense. Gravity is something that we like to feel like we understand. After all, it is really very simple, at least if you're using Newtonian physics, which is great for most things, including this conversation. Armed with such knowledge, our brains easily make a lot of assumptions about how galaxies work by looking at photos of them. Doing some simulation work quickly checks those assumptions and forces one to reconsider them.

I don't know when exactly I started understanding this. Probably after fooling around for quite a number of hours in Blender with some basic particle physics simulations. If you do some reading, make sure you include some videos. Text really doesn't do it any justice. And make sure they're a variety of videos. I'm not sure there is a single most right answer, or I'd just throw a link your way. Some simulations are more sophisticated than others.
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