14 ms·

Misinterpreting hurricane forecasts

125 points by tysone 7y ago

timerol 7y ago
The bottom line of the article is that we should use better and more understandable metrics about a hurricanes path, like https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/174008.shtml?tswind120#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/174008.s..., which was referenced in the article
- thermonot 7y ago
  Now go to the NYT main hurricane article and what do you see? The same misleading map that this article says people don't understand instead of the better wind speed probability alternative: https://www.nytimes.com/2019/08/29/us/hurricane-dorian-florida-updates.html https://www.nytimes.com/2019/08/29/us/hurricane-dorian-flori...
  - dandelany 7y ago
    This one? https://www.nytimes.com/interactive/2019/08/27/us/hurricane-dorian-map.html https://www.nytimes.com/interactive/2019/08/27/us/hurricane-... This is not the same cone map, the shaded area represents "50 percent or higher chance of experiencing wind speeds of at least 39 miles per hour" - ie. a simplified version of the map you recommend.
- felideon 7y ago
  Yes, that one is a good one to monitor, because even Tropical Force Storm winds, when sustained long enough, can wreak significant havoc. This one is also quite informative. It gives you a better idea of when you should have your house ready: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.shtml?mltoa34#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.s...
- krebby 7y ago
  IMO this chart still doesn't adequately explain the data. That color scale reads to me like storm intensity. The crux of the problem is that visualizing uncertainty is hard (remember the NYT 2016 election needles?) especially in a geospatial context where screen X and Y are meaningful. Animation can certainly help but interaction is even better.
marksomnian 7y ago
For this exact reason, the image of the cone on the NHC website [0] has the following disclaimer on the top: "Note: The cone contains the probable path of the storm center but does not show the size of the storm. Hazardous conditions can occur outside of the cone." But apparently media organisations repost that image without the added disclaimer. [0]: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.shtml?cone#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.s...
- mehrdadn 7y ago
  Even reading that, I wouldn't expect the implications to fully sink in for everyone immediately. It's really unintuitive.
bluetidepro 7y ago
Wow, this is fascinating. I had no idea, either. I def always thought what they showed people thought wrongly. Granted, I don't live anywhere near these areas so it's never anything I have had to worry about in real life, but still fascinating and interesting to learn about it more. Very useful to know.
Clubber 7y ago
I live in a hurricane area. We don't use the news for any information other than watching the weatherman stand in the storm and film, and satellite imagery while it's going on. We use noaa.gov, it has all those prediction maps. It's very good. Here's Dorian's maps: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144923.shtml?cone https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144923.s... For those that haven't been through these, the predictions do shift up to the last minute, so we'll check the maps every few hours just to see where it's headed. They update more frequently the closer it gets. Dorian's path seems to have moved a little south since this morning. Also, most areas aren't what you see on the news; they like to show the exception areas as the norm (shocker).
- frgotmylogin 7y ago
  I'm also in a hurricane area - I understand, use, and really like the NHC maps as well. I'm not sure what those red cones in the slideshow were, but the definitely weren't NHC graphics.
- tsumnia 7y ago
  I "still" live in a hurricane area, but less so than when I lived at the beach. As OP mentions, I only use NOAA's page. Anything else is flair or outright deception [1]. Florence was bad, but the video clearly shows the reporter hamming it up. There are people that simply cannot afford to evacuate or otherwise choose not to. When I first moved to Wilmington, I was scared of Category 1's. After living there for a decade, I didn't even prepare for anything less than a Cat 4 - unless you count grabbing beer for the inevitable "hurricane party". While I will accept the articles premise that people can't understand graphs, my major issue is in the study [2] they refer to. The surveys are all retrospectives on assessing uncertainty after the fact. It would be like asking people why they thought a stock would go up when it ended up going down. In the end, who's to blame? Where do we direct the pitchforks? Or is it simply a call to learning how the charts work? If it is the 3rd option, then Times is fearmongering a little hard in my option. [1] https://www.youtube.com/watch?v=ZyrRCx8-fZk https://www.youtube.com/watch?v=ZyrRCx8-fZk [2] https://pdfs.semanticscholar.org/f7c0/4b6eb883cf7d7fdee007cda056ed18182829.pdf https://pdfs.semanticscholar.org/f7c0/4b6eb883cf7d7fdee007cd...
mattfm 7y ago
"Graphics like these need to be read closely and carefully. Only then can we grasp what they're really saying." A cone showing the likely paths of the storm's eye seems like the incorrect graphic to communicate to the public. The public cares about how much rain and wind they are going to get. The take-away to me is that maybe we should just emphasize maps of expected cumulative rainfall and wind speed, and not present something that is uninformative (or prone to misinterpretation) to begin with.
- dmurray 7y ago
  "expected" is perhaps the wrong metric here. There's a difference between being certain of getting 10mm of rain and 20 km/h winds, and a 10% chance of 100mm rain and 200 km/h winds, and you want people to prepare accordingly. The thrust of the article - although it can't state it directly and frames it as a graphics/communications issue - is that more people should prepare for hurricanes, that the cost of more false positives outweighs the downsides of increased false negatives.
- lutorm 7y ago
  Yes, there are wind speed probability plots that show the currently forecasted probability of getting tropical-storm, hurricane and greater-than-hurricane (don't remember) plots that are more useful for judging risk.
acchow 7y ago
"The National Hurricane Center says cones will contain the path of the storm center only 60 to 70 percent of the time" Sounds like the communications fix is easy. Increase the uncertainty to 90-95% which also increases the cone size. And make it blood red and tell anyone inside the red that they need to be prepared. "Hurricanes are also hundreds of miles wide, and the cone shows only the possible path of the storm’s center" Add an additional yellow area around it. This makes it extra clear visually that the red zone is quite bad.
- dmurray 7y ago
  Right. Some of the "popular interpretations" dismissed in the article are correct, or wrong only in degree rather than in kind. Your home is more in danger inside the cone than out of it, and it is more in danger at the centre of the projected path than at the fringes of the cone. If the problem is that people with a low to moderate risk of losing their home or their lives don't prepare enough, then yeah, show a wider area, or the two-level nuance of "red threat" and "yellow threat". And balance it against the inevitable "well, the last four times the government said there was a storm threat it didn't come near here, hell, the last time it made landfall 400 miles away".
  - lonelappde 7y ago
    But probably is not intensity. Half chance of full intensity doesn't mean full chance of half intensity. If you'd evacuate the red zone but not the yellow understand, do you really understand the bet you are making?
- frgotmylogin 7y ago
  I think that would be a pretty big cone. You might end up with the situation where nobody takes it seriously - "oh I was in the last 5 cones this year and didn't get a single drop of rain" type of attitude.
- JustSomeNobody 7y ago
  > prepared And tell them how to prepare. Florida native and I've live here all my life. If you're within the radius of hurricane force winds, live near the coast, live in a flood prone area, live in a shed, live in a trailer, you should take these storms seriously. If you're inland, and not in a shed or trailer, you should be fine if you don't do something stupid, like stand outside. Don't go out and hurricanes are rarely more than a nuisance to those inland. This is a compact storm; it's HFW extend out 15 miles. Anyone outside of that and not on the coast isn't going to have much to worry about.
Ancalagon 7y ago
Looks like the scientific illiteracy sponsored by this country's education system is really starting to pay off!
- amluto 7y ago
  What kind of scientific literacy would make this obvious? They need a better presentation.
  - Ancalagon 7y ago
    confidence intervals...
    - choward 7y ago
      Ok, so what if I live just outside the cone? What does that mean? The map is the same color for 1 mile from the cone and 1,000 miles from the cone. The map is flawed not the people looking at it.
      - Ancalagon 7y ago
        I mean take a look at this bell curve chart with a 0.95 confidence interval (what I assumed the confidence interval of the hurricane path was): https://www.statisticshowto.datasciencecentral.com/wp-content/uploads/2014/12/ci95.png https://www.statisticshowto.datasciencecentral.com/wp-conten... Its all one color...
    - amluto 7y ago
      So a scientifically literate person who understands confidence intervals looks at that plot. How do they tell how likely they are to get hit? Keep in mind that the size of the hurricane isn’t shown at all. You have to real about halfway through the fine print to learn: Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. It does not say the distribution is Gaussian, and I suspect it’s actually much longer-railed than a Gaussian would be.
40acres 7y ago
I think the issue is that most people don't understand probability very well, myself included. After reading the explanations I prefer the layout with possible paths color coded by probability -- in this instance it shows that both the West and East coast of Florida should've prepared.
RandomBacon 7y ago
On mobile, the "subscribe" bar at the bottom covers up the text. I had to use a "remove cookie notification" bookmark to be able to read the text. javascript:(function(){(function () {var i, elements = document.querySelectorAll('body *');for (i = 0; i < elements.length; i++) {if (getComputedStyle(elements[i]).position === 'fixed') {elements[i].parentNode.removeChild(elements[i]);}}})();document.querySelector('body').style.setProperty('overflow','auto','important'); document.querySelector('html').style.setProperty('overflow','auto','important');})()
- Wowfunhappy 7y ago
  Oh cool, how frequently does this bookmarklet actually work?
  - penagwin 7y ago
    It appears to just set anything positioned as fixed to being normal instead. Which should be most popups/cookie notifications. Might break certain websites that try to be clever or "artsy" but as a bookmarklet it shouldn't cause any issues.
satokema_work 7y ago
I've worked with this data on a daily basis. It's a cone of probability, which is about as reliable as you think it is. There are gridded wind speed forecasts (still probability) and NWS watches and warnings if you want something more specific. It helps with general preparedness at best. If you're in hurricane alley it serves as a good reminder to be prepared, but not as a notice to pack your car.
allday 7y ago
Wow, this story is annoying me a lot more than I expected. There's a whole lot of shaming of the layperson in here, with a wink wink nudge nudge that if people would just _think a little_, they could save themselves a lot of trouble. > Graphics like these need to be read closely and carefully. Only then can we grasp what they're really saying. Well, that's ridiculous. If these graphics were in an app, we'd tear them apart for the poor user experience. Look at this: https://imgur.com/a/Ko2Z4uM https://imgur.com/a/Ko2Z4uM There is nothing there to indicate that what you're looking at is the probability distribution of the center of the storm. The very obvious interpretation of this graphic, without additional context, is that this cone is the area that could be affected by the hurricane. This is reinforced by: 1. The size of the start of the cone is the same as the size of the hurricane 2. There is a well defined border to the path 3. There is no additional shading outside the cone that indicates "could also face danger" Furthermore, "probable path of the storm center" is not something the general public cares about! That is not the question that needs answered! What people want to know is, "will I be in the path of the hurricane?" Even the official NHC product has its faults: https://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL052019_5day_cone_no_line_and_wind+png/144746_5day_cone_no_line_and_wind.png https://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL05201... There is a big box with a bunch of text at the top of the graphic saying that it is showing the probable path of the storm's center, but does not show the size of the storm. This is different than saying "the storm may extend beyond the edges of the cone". And the next line is "hazardous conditions may occur outside the cone." Okay, every time there's a thunderstorm or 50mph wind gusts, there's an alert in my weather app about hazardous conditions. That information is too vague to be actionable. This doesn't even touch on the design aspects of this graphic, such as how the massive amount of text, size, color, spacing, etc, seems to draw the eye away from that message at the top. But getting back to a point from a previous paragraph, why is this even disseminated widely at all, when this graphic is so misleading and also not what people need to know? Is it the NHS pushing it out to the public? Is it the media? It seems wildly irresponsible. The tropical storm force wind speeds graphic mentioned in TFA would be a much better product to deliver. Or, just create a graphic that is what the article has already identified as the natural interpretation - a cone of the possible area that could be affected by the hurricane! Sorry, but excuses for poor design are a real pet peeve of mine.
- 7y ago
irrational 7y ago
I think I prefer the image that showed all of the possible paths predicted by different computer models, rather a summarizing cone of probability.
deleted 7y ago
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jsight 7y ago
This article is a little bit misleading, unless I am misinterpreting his pictures. But that would be horrible for an article trying to explain pictures. Here is the graphical archive for all 5 day forecasts of Irma: https://www.nhc.noaa.gov/archive/2017/IRMA_graphics.php?product=5day_cone_with_line https://www.nhc.noaa.gov/archive/2017/IRMA_graphics.php?prod... Now note the image that the article depicts for Hurricane Irma with this text: "These misunderstandings have real-world consequences. As Hurricane Irma approached Florida’s east coast in 2017, people near the cone’s center began preparing and even evacuating." The image and the graphical archive do not correlate. Where did the author get this image from? The actual NHC cone covers the entire width of Florida (apart from maybe the smallest western tip of the keys) for days before the storm arrives. Its actually pretty accurate. IMO, this article and its poor visualizations is part of the problem.
- Allower 7y ago
  No doubt its a map they made themselves displayed in their own coverage >_<
- Jabbles 7y ago
  That is very concerning. Here's an article written at the time: https://www.washingtonpost.com/graphics/2017/national/hurricane-irma/?%3Ftid%3D=sm_pg&noredirect=on https://www.washingtonpost.com/graphics/2017/national/hurric... "Forecasting models predicted the storm’s path with relative accuracy."
  - albertocairo 7y ago
    Forecasts are getting better and better, but they still have large uncertainty. The piece explains the cone as the NHC itself explains it. Scroll down here: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/204603.shtml?cone#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/204603.s...
    - albertocairo 7y ago
      These are the most relevant paragraphs: NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast "cone", the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles. It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above. Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.
deleted 7y ago
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Allower 7y ago
If people are actually that stupid, this post will be useless.
choward 7y ago
There are two problems here. People don't know what the cone means. But even if they did, how are they supposed to act on it? It's hard to know what the cone means because it's way too over-simplified and they really shouldn't have that line there. Of course people are going to be confused. Why can't it just be a color coated overlay where different colors mean different probabilities of the hurricanes path? Even if you do know what the cone means, how are you supposed to act on it? What if I live 10 miles from the cone, should I prepare? How about 20 miles? 100 miles? 500 miles? 1,000 miles? And the idea I had doesn't really solve this problem either. How are you supposed to act on the probabilities? If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%?
- lutorm 7y ago
  "How are you supposed to act on the probabilities? If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%?" Everyone has to make their own judgement based on their risk tolerance, but at least that would be the correct data to use. If you need 24/7 power for your medical equipment, you'll probably make a different call than someone who can ride out a month in their well-stocked, off-grid bunker.
- flukus 7y ago
  > If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%? Prepared/unprepared isn't a binary state either and your level of preparation can match the certainty. At 10% check your supplies of water, candles, gas, canned food. At 20% decide if you'll evacuate. At 50% tape/board up the windows.
haubey 7y ago
I grew up in South Florida, and I'm surprised to hear people think the storm is getting bigger over time. I guess that's just something you grow up with knowing down there. People on the west coast tell me they're terrified of hurricanes, and I'm terrified of earthquakes. You can generally get out of the way of a hurricane if you feel you need to... There are of course common sense things to do to be prepared: get bottled water, food, fill your bathtubs with water and a drop of bleach, make sure the car has a full tank of gas. We personally brought my grandparents down from Boca to stay with us. You can do those maybe a week, 4 days out before stores start to get really empty (grandparents can be moved earlier or later). If you have any coconuts palm trees, chop down your coconuts. These are common sense things to do if there's a remote possibility of a tropical storm or hurricane coming your way. But I do think it's a little disingenuous to say that people didn't do enough to prepare if they lived on the west coast, given how quickly the path shifted. Partly because the NHC is generally so good at their predictions. If you saw the earlier map that had Irma going up east coast, and you were in Naples, you wouldn't think about moving, or at least I wouldn't. Our buildings, especially the newer ones, are built to withstand at least some level of wind. My house built in the 90s has held up through multiple Category 3s (Charlie and Wilma). It's of course all luck, and I know plenty of other houses that have had damage, parts of the roof torn off, shattered windows, though nothing catastrophic, built around the same time. I've driven through the outer bands of a tropical storm (not that you should, but I was in high school and we had a back to school party the night before, and I wanted the car to be home). That's not to disparage the work of the NHC. They're great at what they do, and I read pretty much every advisory for every hurricane that's in the Atlantic. When you've got no place to go, a hurricane bearing down on you is a very scary thing. But if I'm in Naples, and 4 days out it looks like it's heading towards Ft. Lauderdale? I'm not making plans to move.
- cowboy69 7y ago
  This is a great comment that accurately (and nonsensationally) depicts what it’s like to live/grow up in a hurricane area.
  - haubey 7y ago
    Thank you. I will say that we are relatively lucky in that we live inland, so we didn't have to worry about storm surge, in a newer suburb that had its power lines underground. We maybe lost 20 minutes of power during Wilma. I have family that lives in East Ft. Lauderdale, they were out of power for two weeks.
savagedata 7y ago
When Irma was making landfall two years ago, I did an animation demonstrating this for r/DataIsBeautiful. [1] The real hurricane path is in red with the forecast at each timestamp in black. If you look at the forecasts through time, you can see that they're frequently off by a distance the width of Florida. (This final graphic is an amalgamation of all the useful comments I got on the original thread. It was a really cool experience getting so much feedback so fast, like a giant collaboration with all of Reddit. You can see the original not-so-beautiful here. [2]) [1] https://github.com/savagedata/hurricane-animation https://github.com/savagedata/hurricane-animation [2] https://www.reddit.com/r/dataisbeautiful/comments/6z0w20/timelapse_of_hurricane_irma_predictions_vs_actual/ https://www.reddit.com/r/dataisbeautiful/comments/6z0w20/tim...
- jsight 7y ago
  It would be great if this also had the cone overlaid on top of it. It is often interesting to read the forecaster's notes along with each of these graphics, as it is fairly common for the "line" to basically just be an average of several models without much expectation for it to be accurate in itself.
mehrdadn 7y ago
If we want to show people a probability map, why not just show maps for "probability of necessary evacuation" or "probability of serious structural damage" or similar? Instead of probability of hurricane center path or whatever that nobody cares about?
2bitencryption 7y ago
Fun fact about Dorian right now: the tried-and-true European system predicts the hurricane will head up the opposite Florida coast as the new-hotness of the updated GFS[0]. Who will be right (or will both be wrong?). Will be interesting to see. [0] https://twitter.com/GregDeeWeather/status/1166685854695383040 https://twitter.com/GregDeeWeather/status/116668585469538304...
75dvtwin 7y ago
Relying on modern day 'journalists' to interpret weather (or anything else requiring domain expertise, for that matter) -- is very questionable. Why not use windy.com pick a model (the exceptionally well designed UI, makes it easy), and let it play out the tracks. https://www.windy.com/22.837/-67.544?27.897,-66.753,5 https://www.windy.com/22.837/-67.544?27.897,-66.753,5 They have 4 models, and it just as easy to use as posting stuff on Instagram or something.. Meteorologists covering those events, are not journalists, which is good. I trust their coverage more.
bogwog 7y ago
Unrelated, but I was SO happy when I finished reading and clicked the back button on my browser and it actually took me back to HN instead of showing me the previous slide.
MarkMc 7y ago
"People who are inside the cone, but far from the center, tend to prepare less than those closer to the central line. All of these interpretations of the map are incorrect" I'd assume people closer to the central line have a greater chance of being hit. Is the auther saying people with a greater chance of being hit shouldn't prepare more?
- brians 7y ago
  Right. People near the center line are all guaranteed to get hit, and should prepare appropriately
ridaj 7y ago
I personally feel like the "spaghetti bundle" representation of the data (where a random sample of potential paths are drawn) was the most straightforward image of the uncertainty embedded in the forecast. Has it been considered as a means of public communication?
- duanem 7y ago
  I've just implemented this in Flowx[1], the Android weather app I develop. I have the "spaghetti bundle" but it was a major improvement when I added dots indicating the location of the hurricane center with time, as shown in this YouTube video[2] [1] https://play.google.com/store/apps/details?id=com.enzuredigital.weatherbomb https://play.google.com/store/apps/details?id=com.enzuredigi... [2] https://www.youtube.com/watch?v=I46IJcnf_bY https://www.youtube.com/watch?v=I46IJcnf_bY
  - duanem 7y ago
    BTW, these are ensemble models for the NOAA GFS (FV3) and CMC GDPS models. Ensemble models are where the starting conditions of weather simulation is perturbed slightly and the simulations re-solved. They do this 20-odd times and you end up with 20-odd tracks. So for both GFS and GDPS there will give 40-odd paths. Sometimes, it can be interesting how the cluster of GFS tracks may differ from the GDPS tracks.
  - ridaj 7y ago
    These look very cool!!
deleted 7y ago
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jobigoud 7y ago
It's the first time I see this kind of graphic, but that cone looks very suspiciously narrow and smooth, especially in the later days. Are they really properly compounding the probabilities here? Like to create the boundary for the second day you have to sample a number of possible positions from the first day, recompute a possible path from these samples, and then expand the area out of these forwarded samples, based on uncertainty. The boundary at day 2 should be related to the samples that went the most off course. It looks like they just restart from the best-guess predicted position for day 2 which is already based on a prediction for day 1, and multiply it with the uncertainty, with a factor to account for one passing day. If that's the case this is really misleading. I imagine if they did it the way I'm thinking the cone could get very large very fast, but most importantly it wouldn't be smooth and symmetrical like this.
sambe 7y ago
Three main misinterpretations: 1) Getting bigger over time. 2) Safe outside the cone. 3) Further from centre implies less preparation required. 1) Is maybe true anyway? I have no idea. Is it an important error? 2) Is more of a problem with the chart than the people. There's a hard border. It implies 95/99.7% confidence instead of 68%. Were the graph more intuitively designed, the interpretation would not be wrong, really, insofar as one maps probability to a binary choice. 3) Seems completely logical - the expected threat is lower further from the centre. People are still underestimating the risk, but for the same reason as 2).
OrgNet 7y ago
Forecasts from multiple sources gathered here: https://www.spaghettimodels.com/ https://www.spaghettimodels.com/
gdubs 7y ago
I’ve always thought the term “Cone of Uncertainty” sounded like something out of a kitschy TV show from the 1960s. The “spaghetti models” are what I tend to look at. A blend between those and the cone might alleviate some of the confusion about what the cone represents. But a serious question: is this about the general public becoming more distracted? Did people not understand these graphics two decades ago?

125 points by tysone 7y ago

The bottom line of the article is that we should use better and more understandable metrics about a hurricanes path, like https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/174008.shtml?tswind120#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/174008.s..., which was referenced in the article

thermonot 7y ago
Now go to the NYT main hurricane article and what do you see? The same misleading map that this article says people don't understand instead of the better wind speed probability alternative: https://www.nytimes.com/2019/08/29/us/hurricane-dorian-florida-updates.html https://www.nytimes.com/2019/08/29/us/hurricane-dorian-flori...
- dandelany 7y ago
  This one? https://www.nytimes.com/interactive/2019/08/27/us/hurricane-dorian-map.html https://www.nytimes.com/interactive/2019/08/27/us/hurricane-... This is not the same cone map, the shaded area represents "50 percent or higher chance of experiencing wind speeds of at least 39 miles per hour" - ie. a simplified version of the map you recommend.
felideon 7y ago
Yes, that one is a good one to monitor, because even Tropical Force Storm winds, when sustained long enough, can wreak significant havoc. This one is also quite informative. It gives you a better idea of when you should have your house ready: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.shtml?mltoa34#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.s...
krebby 7y ago
IMO this chart still doesn't adequately explain the data. That color scale reads to me like storm intensity. The crux of the problem is that visualizing uncertainty is hard (remember the NYT 2016 election needles?) especially in a geospatial context where screen X and Y are meaningful. Animation can certainly help but interaction is even better.

marksomnian 7y ago

For this exact reason, the image of the cone on the NHC website [0] has the following disclaimer on the top: "Note: The cone contains the probable path of the storm center but does not show the size of the storm. Hazardous conditions can occur outside of the cone." But apparently media organisations repost that image without the added disclaimer. [0]: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.shtml?cone#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144746.s...

mehrdadn 7y ago
Even reading that, I wouldn't expect the implications to fully sink in for everyone immediately. It's really unintuitive.

bluetidepro 7y ago

Wow, this is fascinating. I had no idea, either. I def always thought what they showed people thought wrongly. Granted, I don't live anywhere near these areas so it's never anything I have had to worry about in real life, but still fascinating and interesting to learn about it more. Very useful to know.

Clubber 7y ago

I live in a hurricane area. We don't use the news for any information other than watching the weatherman stand in the storm and film, and satellite imagery while it's going on. We use noaa.gov, it has all those prediction maps. It's very good. Here's Dorian's maps: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144923.shtml?cone https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/144923.s... For those that haven't been through these, the predictions do shift up to the last minute, so we'll check the maps every few hours just to see where it's headed. They update more frequently the closer it gets. Dorian's path seems to have moved a little south since this morning. Also, most areas aren't what you see on the news; they like to show the exception areas as the norm (shocker).

frgotmylogin 7y ago
I'm also in a hurricane area - I understand, use, and really like the NHC maps as well. I'm not sure what those red cones in the slideshow were, but the definitely weren't NHC graphics.
tsumnia 7y ago
I "still" live in a hurricane area, but less so than when I lived at the beach. As OP mentions, I only use NOAA's page. Anything else is flair or outright deception [1]. Florence was bad, but the video clearly shows the reporter hamming it up. There are people that simply cannot afford to evacuate or otherwise choose not to. When I first moved to Wilmington, I was scared of Category 1's. After living there for a decade, I didn't even prepare for anything less than a Cat 4 - unless you count grabbing beer for the inevitable "hurricane party". While I will accept the articles premise that people can't understand graphs, my major issue is in the study [2] they refer to. The surveys are all retrospectives on assessing uncertainty after the fact. It would be like asking people why they thought a stock would go up when it ended up going down. In the end, who's to blame? Where do we direct the pitchforks? Or is it simply a call to learning how the charts work? If it is the 3rd option, then Times is fearmongering a little hard in my option. [1] https://www.youtube.com/watch?v=ZyrRCx8-fZk https://www.youtube.com/watch?v=ZyrRCx8-fZk [2] https://pdfs.semanticscholar.org/f7c0/4b6eb883cf7d7fdee007cda056ed18182829.pdf https://pdfs.semanticscholar.org/f7c0/4b6eb883cf7d7fdee007cd...

mattfm 7y ago

"Graphics like these need to be read closely and carefully. Only then can we grasp what they're really saying." A cone showing the likely paths of the storm's eye seems like the incorrect graphic to communicate to the public. The public cares about how much rain and wind they are going to get. The take-away to me is that maybe we should just emphasize maps of expected cumulative rainfall and wind speed, and not present something that is uninformative (or prone to misinterpretation) to begin with.

dmurray 7y ago
"expected" is perhaps the wrong metric here. There's a difference between being certain of getting 10mm of rain and 20 km/h winds, and a 10% chance of 100mm rain and 200 km/h winds, and you want people to prepare accordingly. The thrust of the article - although it can't state it directly and frames it as a graphics/communications issue - is that more people should prepare for hurricanes, that the cost of more false positives outweighs the downsides of increased false negatives.
lutorm 7y ago
Yes, there are wind speed probability plots that show the currently forecasted probability of getting tropical-storm, hurricane and greater-than-hurricane (don't remember) plots that are more useful for judging risk.

acchow 7y ago

"The National Hurricane Center says cones will contain the path of the storm center only 60 to 70 percent of the time" Sounds like the communications fix is easy. Increase the uncertainty to 90-95% which also increases the cone size. And make it blood red and tell anyone inside the red that they need to be prepared. "Hurricanes are also hundreds of miles wide, and the cone shows only the possible path of the storm’s center" Add an additional yellow area around it. This makes it extra clear visually that the red zone is quite bad.

dmurray 7y ago
Right. Some of the "popular interpretations" dismissed in the article are correct, or wrong only in degree rather than in kind. Your home is more in danger inside the cone than out of it, and it is more in danger at the centre of the projected path than at the fringes of the cone. If the problem is that people with a low to moderate risk of losing their home or their lives don't prepare enough, then yeah, show a wider area, or the two-level nuance of "red threat" and "yellow threat". And balance it against the inevitable "well, the last four times the government said there was a storm threat it didn't come near here, hell, the last time it made landfall 400 miles away".
- lonelappde 7y ago
  But probably is not intensity. Half chance of full intensity doesn't mean full chance of half intensity. If you'd evacuate the red zone but not the yellow understand, do you really understand the bet you are making?
frgotmylogin 7y ago
I think that would be a pretty big cone. You might end up with the situation where nobody takes it seriously - "oh I was in the last 5 cones this year and didn't get a single drop of rain" type of attitude.
JustSomeNobody 7y ago
> prepared And tell them how to prepare. Florida native and I've live here all my life. If you're within the radius of hurricane force winds, live near the coast, live in a flood prone area, live in a shed, live in a trailer, you should take these storms seriously. If you're inland, and not in a shed or trailer, you should be fine if you don't do something stupid, like stand outside. Don't go out and hurricanes are rarely more than a nuisance to those inland. This is a compact storm; it's HFW extend out 15 miles. Anyone outside of that and not on the coast isn't going to have much to worry about.

Ancalagon 7y ago

Looks like the scientific illiteracy sponsored by this country's education system is really starting to pay off!

amluto 7y ago
What kind of scientific literacy would make this obvious? They need a better presentation.
- Ancalagon 7y ago
  confidence intervals...
  - choward 7y ago
    Ok, so what if I live just outside the cone? What does that mean? The map is the same color for 1 mile from the cone and 1,000 miles from the cone. The map is flawed not the people looking at it.
    - Ancalagon 7y ago
      I mean take a look at this bell curve chart with a 0.95 confidence interval (what I assumed the confidence interval of the hurricane path was): https://www.statisticshowto.datasciencecentral.com/wp-content/uploads/2014/12/ci95.png https://www.statisticshowto.datasciencecentral.com/wp-conten... Its all one color...
  - amluto 7y ago
    So a scientifically literate person who understands confidence intervals looks at that plot. How do they tell how likely they are to get hit? Keep in mind that the size of the hurricane isn’t shown at all. You have to real about halfway through the fine print to learn: Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. It does not say the distribution is Gaussian, and I suspect it’s actually much longer-railed than a Gaussian would be.

40acres 7y ago

I think the issue is that most people don't understand probability very well, myself included. After reading the explanations I prefer the layout with possible paths color coded by probability -- in this instance it shows that both the West and East coast of Florida should've prepared.

RandomBacon 7y ago

On mobile, the "subscribe" bar at the bottom covers up the text. I had to use a "remove cookie notification" bookmark to be able to read the text. javascript:(function(){(function () {var i, elements = document.querySelectorAll('body *');for (i = 0; i < elements.length; i++) {if (getComputedStyle(elements[i]).position === 'fixed') {elements[i].parentNode.removeChild(elements[i]);}}})();document.querySelector('body').style.setProperty('overflow','auto','important'); document.querySelector('html').style.setProperty('overflow','auto','important');})()

Wowfunhappy 7y ago
Oh cool, how frequently does this bookmarklet actually work?
- penagwin 7y ago
  It appears to just set anything positioned as fixed to being normal instead. Which should be most popups/cookie notifications. Might break certain websites that try to be clever or "artsy" but as a bookmarklet it shouldn't cause any issues.

satokema_work 7y ago

I've worked with this data on a daily basis. It's a cone of probability, which is about as reliable as you think it is. There are gridded wind speed forecasts (still probability) and NWS watches and warnings if you want something more specific. It helps with general preparedness at best. If you're in hurricane alley it serves as a good reminder to be prepared, but not as a notice to pack your car.

allday 7y ago

Wow, this story is annoying me a lot more than I expected. There's a whole lot of shaming of the layperson in here, with a wink wink nudge nudge that if people would just _think a little_, they could save themselves a lot of trouble. > Graphics like these need to be read closely and carefully. Only then can we grasp what they're really saying. Well, that's ridiculous. If these graphics were in an app, we'd tear them apart for the poor user experience. Look at this: https://imgur.com/a/Ko2Z4uM https://imgur.com/a/Ko2Z4uM There is nothing there to indicate that what you're looking at is the probability distribution of the center of the storm. The very obvious interpretation of this graphic, without additional context, is that this cone is the area that could be affected by the hurricane. This is reinforced by: 1. The size of the start of the cone is the same as the size of the hurricane 2. There is a well defined border to the path 3. There is no additional shading outside the cone that indicates "could also face danger" Furthermore, "probable path of the storm center" is not something the general public cares about! That is not the question that needs answered! What people want to know is, "will I be in the path of the hurricane?" Even the official NHC product has its faults: https://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL052019_5day_cone_no_line_and_wind+png/144746_5day_cone_no_line_and_wind.png https://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL05201... There is a big box with a bunch of text at the top of the graphic saying that it is showing the probable path of the storm's center, but does not show the size of the storm. This is different than saying "the storm may extend beyond the edges of the cone". And the next line is "hazardous conditions may occur outside the cone." Okay, every time there's a thunderstorm or 50mph wind gusts, there's an alert in my weather app about hazardous conditions. That information is too vague to be actionable. This doesn't even touch on the design aspects of this graphic, such as how the massive amount of text, size, color, spacing, etc, seems to draw the eye away from that message at the top. But getting back to a point from a previous paragraph, why is this even disseminated widely at all, when this graphic is so misleading and also not what people need to know? Is it the NHS pushing it out to the public? Is it the media? It seems wildly irresponsible. The tropical storm force wind speeds graphic mentioned in TFA would be a much better product to deliver. Or, just create a graphic that is what the article has already identified as the natural interpretation - a cone of the possible area that could be affected by the hurricane! Sorry, but excuses for poor design are a real pet peeve of mine.

7y ago

irrational 7y ago

I think I prefer the image that showed all of the possible paths predicted by different computer models, rather a summarizing cone of probability.

deleted 7y ago

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jsight 7y ago

This article is a little bit misleading, unless I am misinterpreting his pictures. But that would be horrible for an article trying to explain pictures. Here is the graphical archive for all 5 day forecasts of Irma: https://www.nhc.noaa.gov/archive/2017/IRMA_graphics.php?product=5day_cone_with_line https://www.nhc.noaa.gov/archive/2017/IRMA_graphics.php?prod... Now note the image that the article depicts for Hurricane Irma with this text: "These misunderstandings have real-world consequences. As Hurricane Irma approached Florida’s east coast in 2017, people near the cone’s center began preparing and even evacuating." The image and the graphical archive do not correlate. Where did the author get this image from? The actual NHC cone covers the entire width of Florida (apart from maybe the smallest western tip of the keys) for days before the storm arrives. Its actually pretty accurate. IMO, this article and its poor visualizations is part of the problem.

Allower 7y ago
No doubt its a map they made themselves displayed in their own coverage >_<
Jabbles 7y ago
That is very concerning. Here's an article written at the time: https://www.washingtonpost.com/graphics/2017/national/hurricane-irma/?%3Ftid%3D=sm_pg&noredirect=on https://www.washingtonpost.com/graphics/2017/national/hurric... "Forecasting models predicted the storm’s path with relative accuracy."
- albertocairo 7y ago
  Forecasts are getting better and better, but they still have large uncertainty. The piece explains the cone as the NHC itself explains it. Scroll down here: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/204603.shtml?cone#contents https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/204603.s...
  - albertocairo 7y ago
    These are the most relevant paragraphs: NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast "cone", the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles. It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above. Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.

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Allower 7y ago

If people are actually that stupid, this post will be useless.

choward 7y ago

There are two problems here. People don't know what the cone means. But even if they did, how are they supposed to act on it? It's hard to know what the cone means because it's way too over-simplified and they really shouldn't have that line there. Of course people are going to be confused. Why can't it just be a color coated overlay where different colors mean different probabilities of the hurricanes path? Even if you do know what the cone means, how are you supposed to act on it? What if I live 10 miles from the cone, should I prepare? How about 20 miles? 100 miles? 500 miles? 1,000 miles? And the idea I had doesn't really solve this problem either. How are you supposed to act on the probabilities? If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%?

lutorm 7y ago
"How are you supposed to act on the probabilities? If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%?" Everyone has to make their own judgement based on their risk tolerance, but at least that would be the correct data to use. If you need 24/7 power for your medical equipment, you'll probably make a different call than someone who can ride out a month in their well-stocked, off-grid bunker.
flukus 7y ago
> If there's a 50% chance, do I prepare? What about 20%? 10%? 5%? 1%? 0.1%? Prepared/unprepared isn't a binary state either and your level of preparation can match the certainty. At 10% check your supplies of water, candles, gas, canned food. At 20% decide if you'll evacuate. At 50% tape/board up the windows.

haubey 7y ago

I grew up in South Florida, and I'm surprised to hear people think the storm is getting bigger over time. I guess that's just something you grow up with knowing down there. People on the west coast tell me they're terrified of hurricanes, and I'm terrified of earthquakes. You can generally get out of the way of a hurricane if you feel you need to... There are of course common sense things to do to be prepared: get bottled water, food, fill your bathtubs with water and a drop of bleach, make sure the car has a full tank of gas. We personally brought my grandparents down from Boca to stay with us. You can do those maybe a week, 4 days out before stores start to get really empty (grandparents can be moved earlier or later). If you have any coconuts palm trees, chop down your coconuts. These are common sense things to do if there's a remote possibility of a tropical storm or hurricane coming your way. But I do think it's a little disingenuous to say that people didn't do enough to prepare if they lived on the west coast, given how quickly the path shifted. Partly because the NHC is generally so good at their predictions. If you saw the earlier map that had Irma going up east coast, and you were in Naples, you wouldn't think about moving, or at least I wouldn't. Our buildings, especially the newer ones, are built to withstand at least some level of wind. My house built in the 90s has held up through multiple Category 3s (Charlie and Wilma). It's of course all luck, and I know plenty of other houses that have had damage, parts of the roof torn off, shattered windows, though nothing catastrophic, built around the same time. I've driven through the outer bands of a tropical storm (not that you should, but I was in high school and we had a back to school party the night before, and I wanted the car to be home). That's not to disparage the work of the NHC. They're great at what they do, and I read pretty much every advisory for every hurricane that's in the Atlantic. When you've got no place to go, a hurricane bearing down on you is a very scary thing. But if I'm in Naples, and 4 days out it looks like it's heading towards Ft. Lauderdale? I'm not making plans to move.

cowboy69 7y ago
This is a great comment that accurately (and nonsensationally) depicts what it’s like to live/grow up in a hurricane area.
- haubey 7y ago
  Thank you. I will say that we are relatively lucky in that we live inland, so we didn't have to worry about storm surge, in a newer suburb that had its power lines underground. We maybe lost 20 minutes of power during Wilma. I have family that lives in East Ft. Lauderdale, they were out of power for two weeks.

savagedata 7y ago

When Irma was making landfall two years ago, I did an animation demonstrating this for r/DataIsBeautiful. [1] The real hurricane path is in red with the forecast at each timestamp in black. If you look at the forecasts through time, you can see that they're frequently off by a distance the width of Florida. (This final graphic is an amalgamation of all the useful comments I got on the original thread. It was a really cool experience getting so much feedback so fast, like a giant collaboration with all of Reddit. You can see the original not-so-beautiful here. [2]) [1] https://github.com/savagedata/hurricane-animation https://github.com/savagedata/hurricane-animation [2] https://www.reddit.com/r/dataisbeautiful/comments/6z0w20/timelapse_of_hurricane_irma_predictions_vs_actual/ https://www.reddit.com/r/dataisbeautiful/comments/6z0w20/tim...

jsight 7y ago
It would be great if this also had the cone overlaid on top of it. It is often interesting to read the forecaster's notes along with each of these graphics, as it is fairly common for the "line" to basically just be an average of several models without much expectation for it to be accurate in itself.

mehrdadn 7y ago

If we want to show people a probability map, why not just show maps for "probability of necessary evacuation" or "probability of serious structural damage" or similar? Instead of probability of hurricane center path or whatever that nobody cares about?

2bitencryption 7y ago

Fun fact about Dorian right now: the tried-and-true European system predicts the hurricane will head up the opposite Florida coast as the new-hotness of the updated GFS[0]. Who will be right (or will both be wrong?). Will be interesting to see. [0] https://twitter.com/GregDeeWeather/status/1166685854695383040 https://twitter.com/GregDeeWeather/status/116668585469538304...

75dvtwin 7y ago

Relying on modern day 'journalists' to interpret weather (or anything else requiring domain expertise, for that matter) -- is very questionable. Why not use windy.com pick a model (the exceptionally well designed UI, makes it easy), and let it play out the tracks. https://www.windy.com/22.837/-67.544?27.897,-66.753,5 https://www.windy.com/22.837/-67.544?27.897,-66.753,5 They have 4 models, and it just as easy to use as posting stuff on Instagram or something.. Meteorologists covering those events, are not journalists, which is good. I trust their coverage more.

bogwog 7y ago

Unrelated, but I was SO happy when I finished reading and clicked the back button on my browser and it actually took me back to HN instead of showing me the previous slide.

MarkMc 7y ago

"People who are inside the cone, but far from the center, tend to prepare less than those closer to the central line. All of these interpretations of the map are incorrect" I'd assume people closer to the central line have a greater chance of being hit. Is the auther saying people with a greater chance of being hit shouldn't prepare more?

brians 7y ago
Right. People near the center line are all guaranteed to get hit, and should prepare appropriately

ridaj 7y ago

I personally feel like the "spaghetti bundle" representation of the data (where a random sample of potential paths are drawn) was the most straightforward image of the uncertainty embedded in the forecast. Has it been considered as a means of public communication?

duanem 7y ago
I've just implemented this in Flowx[1], the Android weather app I develop. I have the "spaghetti bundle" but it was a major improvement when I added dots indicating the location of the hurricane center with time, as shown in this YouTube video[2] [1] https://play.google.com/store/apps/details?id=com.enzuredigital.weatherbomb https://play.google.com/store/apps/details?id=com.enzuredigi... [2] https://www.youtube.com/watch?v=I46IJcnf_bY https://www.youtube.com/watch?v=I46IJcnf_bY
- duanem 7y ago
  BTW, these are ensemble models for the NOAA GFS (FV3) and CMC GDPS models. Ensemble models are where the starting conditions of weather simulation is perturbed slightly and the simulations re-solved. They do this 20-odd times and you end up with 20-odd tracks. So for both GFS and GDPS there will give 40-odd paths. Sometimes, it can be interesting how the cluster of GFS tracks may differ from the GDPS tracks.
- ridaj 7y ago
  These look very cool!!

deleted 7y ago

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jobigoud 7y ago

It's the first time I see this kind of graphic, but that cone looks very suspiciously narrow and smooth, especially in the later days. Are they really properly compounding the probabilities here? Like to create the boundary for the second day you have to sample a number of possible positions from the first day, recompute a possible path from these samples, and then expand the area out of these forwarded samples, based on uncertainty. The boundary at day 2 should be related to the samples that went the most off course. It looks like they just restart from the best-guess predicted position for day 2 which is already based on a prediction for day 1, and multiply it with the uncertainty, with a factor to account for one passing day. If that's the case this is really misleading. I imagine if they did it the way I'm thinking the cone could get very large very fast, but most importantly it wouldn't be smooth and symmetrical like this.

sambe 7y ago

Three main misinterpretations: 1) Getting bigger over time. 2) Safe outside the cone. 3) Further from centre implies less preparation required. 1) Is maybe true anyway? I have no idea. Is it an important error? 2) Is more of a problem with the chart than the people. There's a hard border. It implies 95/99.7% confidence instead of 68%. Were the graph more intuitively designed, the interpretation would not be wrong, really, insofar as one maps probability to a binary choice. 3) Seems completely logical - the expected threat is lower further from the centre. People are still underestimating the risk, but for the same reason as 2).

OrgNet 7y ago

Forecasts from multiple sources gathered here: https://www.spaghettimodels.com/ https://www.spaghettimodels.com/

gdubs 7y ago

I’ve always thought the term “Cone of Uncertainty” sounded like something out of a kitschy TV show from the 1960s. The “spaghetti models” are what I tend to look at. A blend between those and the cone might alleviate some of the confusion about what the cone represents. But a serious question: is this about the general public becoming more distracted? Did people not understand these graphics two decades ago?