2013 - The National Hurricane Center’s (NHC) Cone is Smaller

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2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#1 Postby Dave » Mon May 13, 2013 11:18 am

Each year, NHC’s team of meteorologists analyzes the center’s forecast track errors from the past five tropical seasons, then averages them out. In the past five years storm path predictions have become steadily more accurate so for this year, 2013, the cone is slightly smaller.

It is very important to remember that the storm can be anywhere in that cone 67 percent of the time, and is in no way representative of the areas that would feel the impacts of the storm. In the upcoming season, the cone will be about 9 percent smaller than last year in 2012.

The part of the cone that shows when a storm is five days out will be 526 miles across, 24 miles less than last year; four days out, 406 miles across, or 30 miles less and three days out, 294 miles across, or 36 miles less. The part of the cone that shows when a storm is two days out will be 212 miles across, or 14 miles less than last year; 36 hours out, 166 miles across, or 16 miles less; 24 hours out, 120 miles across, or 8 miles less; and for 12 hours out, 76 miles across, or 3 miles less.

One caveat do not rely 100% on the cone at any time because some storms will travel outside of it plus the tropical storm force winds may be well out of the actual cone so use the cone for information but do not make life and property safety decisions based solely on the NHC Cone of Error.

More details for the new National Hurricane Center's 2013 Cone of Error may be found here:

http://www.nhc.noaa.gov/aboutcone.shtml

Anyone who wants to add to this thread feel free to do so at anytime.
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#2 Postby Dave » Thu May 16, 2013 9:17 pm

Put together by Artist (Thank You)

artist wrote:I know there are probably those here that have not experinced a hurricane before, or it has been many, many years since. It can be a trying time trying to decide what you need, etc. Here at storm2k, through the years, the participants have put together a forum that tells you what they either forget and needed or the veterans letting us know what they get together for their hurrucane preps.
You can find this forum here -
Hurricane Preparation
viewforum.php?f=30&st=0&sk=t&sd=d&start=0
and here is the direct link to the lists people have put together-
viewtopic.php?f=30&t=58904
There is also a thread about Hurricane Preparations for Pets-
viewtopic.php?f=30&t=108380
Be sure to explore the first link as there is all sorts of good advice youcan get there for hurricane prep. There is also another forum for hurricane recovery & aftermath-
viewforum.php?f=33
Explore these forums, as they will help you decide what you need to do, if you are to be affected by Earl.
Know many of us here have been there, done that, and our thoughts and prayers are with you all.
Be sure to post your reports to our Reports thread on the Active Storms forums here as you can -
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and be sure to check in there after the storm so we know you all are ok.
It can be the pits, but you can feel empowered by getting yourselves ready, and knowing where to start, and you will get through this. Just think ahead & think smart.
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#3 Postby WeatherGuesser » Fri May 17, 2013 2:17 am

The part of the cone that shows when a storm is five days out will be 526 miles across, 24 miles less than last year; four days out, 406 miles across, or 30 miles less and three days out, 294 miles across, or 36 miles less. The part of the cone that shows when a storm is two days out will be 212 miles across, or 14 miles less than last year; 36 hours out, 166 miles across,


I don't understand why they use such oddball numbers. Why not stick with increments of 25? Maybe even 10. In charts like these, there is no difference between 526 and 525 or 294 and 300.

If they're using some sort of Metric or Nautical scale internally, convert it to even increments for public postings.
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#4 Postby senorpepr » Sat May 18, 2013 8:41 pm

WeatherGuesser wrote:
The part of the cone that shows when a storm is five days out will be 526 miles across, 24 miles less than last year; four days out, 406 miles across, or 30 miles less and three days out, 294 miles across, or 36 miles less. The part of the cone that shows when a storm is two days out will be 212 miles across, or 14 miles less than last year; 36 hours out, 166 miles across,


I don't understand why they use such oddball numbers. Why not stick with increments of 25? Maybe even 10. In charts like these, there is no difference between 526 and 525 or 294 and 300.

If they're using some sort of Metric or Nautical scale internally, convert it to even increments for public postings.


I guess my point of view is why not use the actual numbers rather than round? The cone is a visual display anyway and the raw numbers of the cone aren't usually for public consumption anyway. So why not have the cone at 294 mi at the 72-hour point rather than 300 mi. The cone is a 5-year average. What's the harm with using that raw, averaged number versus a rounded figure?
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#5 Postby greenkat » Mon Jun 03, 2013 9:28 pm

Interesting... Glad to see we're getting more accurate :)
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#6 Postby Alyono » Thu Aug 17, 2017 7:15 am

if anything, the cone needs to be removed all together as it says nothing about the forecast uncertainty. It only addresses historical errors
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#7 Postby tolakram » Thu Aug 17, 2017 7:31 am

Keep the cone, remove all lines. A line without any cone would be a deadly mistake IMO.

As far as accuracy, the NHC has generally improved every year, you can find their verification information on this page: http://www.nhc.noaa.gov/verification/verify5.shtml

Do NOT confuse modeling with forecasting. Forecasters use models as tools, many here tend to use models as something they are not. :)

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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#8 Postby Alyono » Thu Aug 17, 2017 8:04 am

tolakram wrote:Keep the cone, remove all lines. A line without any cone would be a deadly mistake IMO.

As far as accuracy, the NHC has generally improved every year, you can find their verification information on this page: http://www.nhc.noaa.gov/verification/verify5.shtml

Do NOT confuse modeling with forecasting. Forecasters use models as tools, many here tend to use models as something they are not. :)

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cone would not be replaced by a line, but a swath that shows the true uncertainty
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#9 Postby RL3AO » Thu Aug 17, 2017 8:08 am

Yep. The cone needs to be dynamic based on some metric of forecast confidence. Gert would have had a smaller cone for example.
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#10 Postby MJGarrison » Mon Oct 02, 2017 6:49 pm

RL3AO wrote:Yep. The cone needs to be dynamic based on some metric of forecast confidence. Gert would have had a smaller cone for example.


NHC likely doesn't use a dynamic cone because their forecasting is somewhat subjective; they often lean "closer to the Euro" or "favor the GFS" or "not moving too far in case the models swing back"

To obtain a proper dynamic cone, subjectivity would have to be removed and a move would need to be made to a strictly models based approach.

Until the models outperform the NHC in a consistent fashion, the current cone is probably a better indication of error.
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#11 Postby Alyono » Tue Oct 03, 2017 12:24 pm

MJGarrison wrote:
RL3AO wrote:Yep. The cone needs to be dynamic based on some metric of forecast confidence. Gert would have had a smaller cone for example.


NHC likely doesn't use a dynamic cone because their forecasting is somewhat subjective; they often lean "closer to the Euro" or "favor the GFS" or "not moving too far in case the models swing back"

To obtain a proper dynamic cone, subjectivity would have to be removed and a move would need to be made to a strictly models based approach.

Until the models outperform the NHC in a consistent fashion, the current cone is probably a better indication of error.


that post is a complete MISUNDERSTANDING of the cone. It in no way provides the uncertainty. It strictly provides historical errors. An ensembles based probability swath (which likely is NOT in the shape of a cone) does provide an objective estimate. Preliminary verification has showed that that technique is skillful in representing the true uncertainty
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Re: 2013 - The National Hurricane Center’s (NHC) Cone is Smaller

#12 Postby tolakram » Tue Oct 03, 2017 12:59 pm

MJGarrison wrote:
RL3AO wrote:Yep. The cone needs to be dynamic based on some metric of forecast confidence. Gert would have had a smaller cone for example.


NHC likely doesn't use a dynamic cone because their forecasting is somewhat subjective; they often lean "closer to the Euro" or "favor the GFS" or "not moving too far in case the models swing back"

To obtain a proper dynamic cone, subjectivity would have to be removed and a move would need to be made to a strictly models based approach.

Until the models outperform the NHC in a consistent fashion, the current cone is probably a better indication of error.


There should be no question of what the cone is as it's very simply a circle drawn around each forecast point with the radius set to 2/3 historical forecast error for each point in time.

http://www.nhc.noaa.gov/aboutcone.shtml

The track is somewhat subjective as a blend between the models but the cone around those forecast points is not.

The cone represents the probable track of the center of a tropical cyclone, and is formed by enclosing the area swept out by a set of circles (not shown) along the forecast track (at 12, 24, 36 hours, etc). The size of each circle is set so that two-thirds of historical official forecast errors over a 5-year sample fall within the circle. The circle radii defining the cones in 2017 for the Atlantic and eastern North Pacific basins are given in the table below.
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