# Talk:Dvorak technique

More info. Perhaps you could mention storms where Dvorak constraints were broken. That occurred during Elida during the 2002 EPAC season. Also, what are the highest ones? IIRC, Angela in 1995 got up to an 8, along with 2 other storms. Hurricanehink (talk) 03:42, 22 May 2006 (UTC)

I think the Dvorak constraints are not very useful. They simply, (if my understanding is correct) give a guideline of how fast a typical storm will stregthen. Is based on statistical data, does not consider the environment of the hurricane. Also 8.0 is the highest possible Dvorak number. TimL 03:18, 26 May 2006 (UTC)
Cyclone Monica got an estimate of 8 this year, though unofficially (from the JTWC). —CuiviénenT|C, Wednesday, 24 May 2006 @ 00:22 UTC
Part of the text seems to be cut off at the end.  Also, I've seen a chart somewhere with a column for the minimum pressure estimates for pacific basin storms as they have a lower pressure in general.  I can't remember if it was on the NHC site or in Dvorak's paper itself.  I have it saved somewhere on my computer if you decide to add it and can't locate the numbers. Dr Denim 03:46, 22 May 2006 (UTC)

oh and I just remembered something else worth adding is the usage of the Dvorak technique in forecasting intensity changes Dr Denim 03:57, 22 May 2006 (UTC)
How is the technique used for forecasting intensity changes? TimL 19:25, 23 May 2006 (UTC)
Further research indicates to me that the Dvorak technique is not skilled at forecasting intensity. It is not mentioned by the NHC in their year-end accuracy report, so I don't think it is worth a mention here. TimL 03:18, 26 May 2006 (UTC)
I think it might still be worth mentioning as it is part of the technique even if it isn't used often and I'd assume it is just as reliable as the persistance model for intensity change...can't remember what that was called...Dr Denim 12:25, 26 May 2006 (UTC)
The important thing to remember about the Dvorak technique is that it isn't used as a model to numerically predict intensities, but rather just a "the intensity is increasing/decreasing/steady state" kind of thing, which can just as easily be determined by simply looking at a satellite image. It's more of a predictor of what trend is currently underway in the cyclone's structure/intensity. And since its forecasting role is so limited, and it is not a model of any sort, it isn't mentioned in the NHC's verification reports. WindRunner 18:56, 27 May 2006 (UTC)
okay...I see...i missread the last line Dr Denim 04:01, 22 May 2006 (UTC)
I remember Elida, she was crazy. Discussion of breaking Dvorak: [1] [2] [3]:

ELIDA HAS BROKEN ALL THE DVORAK RULES. IT HAS INTENSIFIED RAPIDLY 
SINCE YESTERDAY AND DATA T-NUMBERS ARE UP TO 6.0 PLUS WITH OBJECTIVE 
NUMBERS REACHING 6.5 DURING THE PAST HOUR OR SO.

-- RattleMan 03:50, 22 May 2006 (UTC)
Something else that might be handy is an example satelite image...and for that matter if we could somehow upload the drawings(or replications of them) of the satelite images for different CI numbers that apear in his essay on the technique that'd be really helpful...if I could find a way to make the images on my computer or get my scanned drawings to look smoother I'd be willing to make them...I have them sketched somewhere...anywhoDr Denim 11:43, 23 May 2006 (UTC)

also...is the essay online somewhere?Dr Denim 11:43, 23 May 2006 (UTC)
Yes, I thought that might be a compelling addition to the article. I have not seen the essay, nor do I know how to access it, but an idea I had was to grab public domain satellite image for storms of a certain CI and show them together. There could be a set of images for several 3.0 CI storms and another set for several 4.0 CI storms. TimL 19:25, 23 May 2006 (UTC)
Sample satellite images, done. Room for improvement here though. TimL 03:18, 26 May 2006 (UTC)
well...if you live near a university that has a meteorology program then they might have one...if I get the chance to stop by school sometime this summer I'll have to try and photocopy the essay so I can have a copy of it on hand...I've looked around the noaa websites for it but haven't had any luck...mayhap I'll look around on google or something...anywho...those reference images would be really helpful in explaining the technique...especially to someone who isn't familiar with the terminology.  I'll look around and see if I can't find a copy of the essay online somewhereDr Denim 20:06, 23 May 2006 (UTC)
here's a link to the abstract so that the citation information can be added by someone at least...still looking for an online version though
Abstract
Dr Denim 20:09, 23 May 2006 (UTC)

ah here's an image of one of the several charts in the paper...the website's messed up on this computer(probably in an asian charater set) so I can't tell if it's public domain or not (although considering the fact that I can't find the essay itself it's probably not public domain)...anywho
chart
and here's another website on the objective version used now
websiteDr Denim 20:25, 23 May 2006 (UTC)
Okay...so I uploaded the notes I took when I read the essay onto my deviant art account...although I never got around to finishing the essay but I got a good chunk of it done...

First Page
Second Page
I think we might want the diagrams from Bureau of Meteorology's Global Guide to Forecasting from the Tropical Cyclone Intensity subsection (click each Figure link). --AySz88^-^ 03:42, 26 May 2006 (UTC)
Could we have a wider range of images showing TCs at various CI's. 2.5, 3.0 and 3.5 isn't much of a range. It should give an impression of how it varies from 2.0 up to 8.0. And ideally it shouldn't be solely Atlantic storms.--Nilfanion (talk) 09:25, 12 June 2006 (UTC)

That is quite reasonable. Other basins are doable as long as they have readily available advisory/discussion archives which mention T-numbers. Since the other basins rely soley on the Dvorak technique(i.e no reconaissance) I would be suprised if they didn't.
Images could also be broken down into the various pattern types, though this would require some skill with the dvorak technique. There is a presenation I should throw in the external links which has drawings of the various pattern types at different intensities. TimL 22:52, 12 June 2006 (UTC)
Corrected the spelling of Jack's last name on the External Links section. Margie 00:45, 12 July 2006 (UTC)

Before time expires, you may want to send it to Did you know... Titoxd(?!? - help us) 03:47, 26 May 2006 (UTC)

Thanks, done. TimL 04:08, 26 May 2006 (UTC)

Accuracy Section
History Section
Some sort of figurative examples of pattern types from sattelite imagery.
Add info from Dvorak's paper (which thanks to Nilfanion (talk · contribs) I realize I could have downloaded all along).
TimL 05:16, 18 June 2006 (UTC)

More info about how the technique is used (from here) Titoxd(?!?) 23:14, 15 December 2006 (UTC)

I removed all references to AFWA (KGWC) providing Dvorak fixes on tropical cyclones.  I work there and know they no longer provide fixes.  This was mentioned in the 2007 National Hurricane Operations Plan.  Also, in the 2007 Office of the Federal Coordinator for Meteorology Action Items list, Point #12, it said the following:
"Due to recent personnel and funding cuts, the Air Force Weather Agency (AFWA) can no longer dedicate the resources needed to sustain tropical cyclone satellite imagery surveillance and analysis support to the National Hurricane Operations Plan. This cessation of support requires changes in the NHOP to reflect the AFWA termination but continuance of support on request, resources permitting, by the 17th Operational Weather Squadron Meteorological Satellite Operations (SATOPS) Flight (17 OWS/WXJ), Joint Typhoon Warning Center, Pearl Harbor, HI to the Central Pacific Hurricane Center.)
-Senorpepr (talk) 06:46, 7 July 2008 (UTC)

As far as I can tell, discussion of the CCC (Central Cold Cover) is missing, as well as any real discussion of its evolution. Thegreatdr (talk) 02:38, 27 September 2012 (UTC)

Since this has been revolved, the article has been GANed.  Thegreatdr (talk) 19:04, 8 October 2012 (UTC)

This review is transcluded from Talk:Dvorak technique/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: Noleander (talk · contribs) 15:42, 21 November 2012 (UTC)
Hi.  I can do this review.   Can the nominator please reply and confirm that they are still interested in working on the article? --Noleander (talk) 15:42, 21 November 2012 (UTC)


### Comments from reviewer
Lead: must mention the more commonly-use  "Level 1 to 5" hurricane intensity scale:  compare and contrast with Dvorak (because readers, at least in US, will have heard the 1-to-5 frequently in the news reports)
The table below compared the T numbers used in the Dvorak scale to hurricane categories.  I don't see why we'd need to add this sort of information into the lead.  The lead is meant to be a broad summary of the article below.  Thegreatdr (talk) 21:06, 21 November 2012 (UTC)
Lead:  Must explain if hurricanes are included or not
I believe I have now addressed this.  Remember that we can't introduce POV into the article, so I've tried to use more global terms.  Tropical cyclones include TD, TS, and HU/TY/Intense TC intensities explicitly.  Thegreatdr (talk) 21:09, 21 November 2012 (UTC)
What is the POV issue?  I thought Hurricane simply means a cyclone in the Atlantic, no?   Many readers will know what  a hurricane is, but will not be familiar with cyclone. --Noleander (talk) 18:26, 23 November 2012 (UTC)
The POV issue is that hurricane is Western Hemisphere-centric.  Thegreatdr (talk) 21:31, 23 November 2012 (UTC)
Footnote in lead:  Why is footnote #1 in the lead section? footnotes are optional there, and all material in lead is supposed to also be in the body (where the footnote should normally be placed).
If you want me to remove it, I can.  Some people who review GA articles demand it, even if it is optional, as you say.  Other references further down the article cover this.  Thegreatdr (talk) 21:12, 21 November 2012 (UTC)
No need to measure wind speed (fly aircraft into?) - I don't see a comparison of Dvorak vs other intensity schemes which require measuring wind speed.  I would think that a HUGE point is that the DT is much simpler/cheaper/safer than flying a plane into a hurricane, etc.   Maybe there could be  an entire section in the article on "DT contrasted with other estimation approaches" or similar.   I see that the section "Evolution" mentions a few other techniques:  consider re-casting that section to be "other techniques" section.
I've added a pro/con section, which borrowed (moved) material from other sections into the new section.  Thegreatdr (talk) 21:47, 21 November 2012 (UTC)
Define: "1-min Winds" in table: needs explanation
I have wikilinked to the maximum sustained wind article, which is a thorough treatment of the topic.  That should address your concern.  Thegreatdr (talk) 21:14, 21 November 2012 (UTC)
Newer picture?  - The chart at top of article looks important historically:  the original 1973 technique.  But its a bit crude.  Doesn't the NOAA have a newer, updated version (public domain) that is cleaner & updated?   The could both be in the article.
The last paper by Dvorak in the public domain is from 1984.  Wikipedia does normally demand original sources.  I have uploaded the two images on the right from the 1984 paper .  An improvement from your perspective?  Thegreatdr (talk) 21:24, 21 November 2012 (UTC)
Ambiguous:  section title "Evolution" is ambiguous:  does it mean evolution of the creation of the technique?  or evolution of a cyclone as it develops?  See also note above about changing the Ev section to be "comparison with other techniques"
See if the new section titles are favorable.  I'm trying to avoid the terms Dvorak and technique in the section headers, per the Manual of Style.  Thegreatdr (talk) 21:32, 21 November 2012 (UTC)
Letter classification V -Z :  The chart at top shows five different development lifespans:  V to Z.  Those needs to be explained in the article.
I've checked the paper, and the letters appear extraneous.  I've removed them from the image.  Thegreatdr (talk) 21:45, 21 November 2012 (UTC)
I'll pause for now.  Go ahead and address the above as you see fit, then notify me on my talk page, and I'll do some more.
Okay, your recent changes are looking great.  Here are a few more thoughts:
Wording: "...use of the Dvorak technique has been to provide a more ..." - Passive grammar.  Try " technique is that it provides a more .."
Fixed.  Thegreatdr (talk) 18:22, 23 November 2012 (UTC)
Wording: "Some tropical cyclones do fluctuate in ..." - Better as " Some tropical cyclones fluctuate in ..."
Fixed.  Thegreatdr (talk) 18:22, 23 November 2012 (UTC)
Fact clarification: "... strength more than the constrained 2.5 T numbers per day,"  - Can that be clarified?  It sounds like there is a rule that storms can only change their value by a maximum of 2.5 per day.  If that is true, that "rule" or constraint should be explicitly mentioned before this sentence, perhaps much earlier in the article.
I have mentioned this tidbit further up in the article, per your suggestion.  Thegreatdr (talk) 18:22, 23 November 2012 (UTC)
Mention other classification system:  The Saffir–Simpson hurricane scale is widely used in the US.  A layman reader will want the article to mention the SSHS, briefly define it, and explain how the Dvorak technique is used in relation to SSH:  are they two different approaches to the same thing?  Or does one just supplement the other?  Why does SSHS only have 5 levels, yet Dvorak has more?  Which system is more widely used by weather professionals in their own writings?  etc.
The reason I haven't mentioned Saffir-Simpson is that it is meant to provide people some idea of what type of wind damage to expect for landfalling systems, while this method is merely assigning tropical cyclone intensity to meteorologists who use the information to then assign the maximum sustained winds.  I can see where one might think they are related, since they both deal with wind, but one is assigning an intensity for meteorologists, while the other is giving the public an idea of the type of damage to expect with tropical cyclones of a certain intensity.  They appeal to two different groups of people.  Thegreatdr (talk) 18:22, 23 November 2012 (UTC)
Red link:  - Probably should create a red link for Hebert-Poteat, per WP:RED, so future readers will have their attention drawn to the fact that a new article needs to be created.  For example, see Extratropical transition technique where it is red-linked.
Done.  Thegreatdr (talk) 18:29, 23 November 2012 (UTC)
Ambiguous - "Subtropical cyclone intensity cannot be determined using this technique, ..." -  Not clear what "this technique" is, since a couple of techniques were mentioned in the preceding few sentences.  Just re-state the name of the technique so reader doesn't have to guess.
Done.  Thegreatdr (talk) 18:29, 23 November 2012 (UTC)
Caption confusing:  "Subtropical Storm Andrea of 2007, a system which the Dvorak technique would improperly diagnose cyclone intensity" - The reader will want a couple more facts on this:  (1) what is it about Andrea that would cause the DT to fail?    and (2) citation needed, since it is identifying a flaw in the DT, the reader may want to go read more about this flaw.  I looked in the article body, but did not see any other metion of Andrea in the article.  Also, the grammar of that caption is not quite right.   Maybe "The Dvorak technique does not correctly diagnose cyclone intensity for storms like Andrea because blah, blah."
Reworded per your suggestion.  Thegreatdr (talk) 18:29, 23 November 2012 (UTC)
I checked disambig links: looks good
I checked external links: looks good
That's about all I can find.  Overall it is a great article, with good graphics and nice prose!  If you can address the points above, it will be GA status.
End comments from Noleander. --15:46, 21 November 2012 (UTC)

Okay, I've marked the article with GA status.  I disagree on the SSHS issue, but I don't think that is a show stopper. --Noleander (talk) 22:02, 23 November 2012 (UTC)
How about including some information from other countries and how they use the Dvorak Technique inc why the JMA doesn't use it. This info should be available in amongst the various presentations provided by the WMO Conference.Jason Rees (talk) 19:22, 23 November 2012 (UTC)
Used information from the reference.  Thanks Jason.  =)  Thegreatdr (talk) 21:30, 23 November 2012 (UTC)

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