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Modern Weather Forecasts Are Stunningly Accurate
- moocowtruck 8y agowhy is my weatherman always wrong? :(
- Niksko 8y agoBecause we tend to remember the few times where they get it very wrong (which is always going to happen because of the chaotic nature of weather) and ignore the large percentage of the time when they're right.
- majewsky 8y agoConfirmation bias.
- brewdad 8y agoBeing "wrong" can be no big deal (48F vs 50) or hugely significant. My town will be getting precipitation this weekend. If the temps stay at 36, it will be a typical cold, wet weekend. If temps fall to 33 or lower, my town will be shutting down for a day or two since we don"t have snowplows.
- saagarjha 8y ago> In 2009, a back-of-the-envelope study estimated that U.S. adults check the weather forecast about 300 billion times per year. That's every single adult in the United States checking the weather four times a day. A bit more than I would have expected…
- arethuza 8y agoI'm not in the US, but as I like spending my weekends doing outdoor activities I check weather forecasts during the week a lot to try and plan what I'm going to do and where. Four times a day doesn't seem that much to me - I'd imagine people who work outdoors and farmers have even more reason to check the weather frequently. [NB I even check multiple sources of weather information: BBC, Windy and MWIS].
- virtualwhys 8y agoI check the Air Quality Index probably 20X per day where I am in Thailand (Chiang Mai). Guess Americans are just neurotic when it comes to the elements. Goes back to shopping for that NASA spacesuit...clean air wherever you go.
- YokoZar 8y agoThis number probably includes things like swiping to the leftmost home screen on your phone to see the weather widget at the top. When it's that easy you can often check the weather unintentionally.
- ams6110 8y agoMy weather check is normally looking out the window. I don't use forecasts very often.
- chaosbutters 8y agoDecember-April, I check a few times a day and different sources for snow/ice since I do not feel comfortable driving and getting caught in it. The number of times increases especially if I'm traveling. So when you time-average this over the year, it makes more sense.
- firebird84 8y agoWhen there's a hurricane incoming during the season, I check more often than that, at least every time the NHC has a new advisory. I imagine severe weather events cause huge surges in activity, it's probably not normally distributed throughout the year.
- chooseaname 8y agoFloridian. During the summer months I check more often (when I'm heading out) so that I know if a T-Storm will be developing in the next couple hours.
- js2 8y agoWait what? I grew up in Miami: the answer is always yes.
- nindalf 8y agoThis is an interesting example of an article that talks about gradual improvements in our lives that we take for granted at this point. It's strange because most articles are about dramatic deterioration. For example, it's unlikely we will read articles about the increase in % children who are vaccinated against basic diseases. It was 22% in 1980, 88% in 2016. Far more likely is reading reams of text devoted to the (for now) niche anti-vaxxer movement.
- neuronic 8y ago> [...] most articles are about dramatic [...] This small snippet of your comment in combination with knowledge about click/ad-based revenue for most outlets is really all you need to make yourself aware of nowadays. Drama is what drove gossip for millennia and with the advent of media it began to drive sales. Doesn't matter if book, TV show or news article. It's all entertainment.
- lotsofpulp 8y agoI don’t think using outbreaks of a preventable disease due to stupid people thinking they know more than they do and causing harm to society as a whole is overly dramatic. If anything, there should be more coverage about it so we can get laws passed to deny non medical exemptions.
- nindalf 8y agoWhat's the impact in terms of affected people. Hundreds of millions of children being vaccinated, millions of them not dying young, dramatically changing the dynamics of societies where women can now choose not to have multiple children.... or a few hundred people getting measles. I'm not saying the anti-vax thing isn't a problem. I'm saying that the improvements and advancements have a higher impact on society than what a few idiots choose to do. And yet we read much more about the latter.
- lotsofpulp 8y agoThe issue of people not vaccinating is specifically one which can spiral out of control very easily, as the tools we have to fight the disease don't work once herd immunity is lost, hence sounding the alarm bells is warranted. Actually, now that I think about it, perhaps if the history of vaccines and the success had been more widely disseminated, then we may not have had this anti vaccine problem. I agree that it would be nice to read more about successes.
- chewz 8y agoJust follow few models for a couple of weeks and you will notice how inaccurate the weather forecast is.* I do follow ECMWF and ICON and a bit of OpenWeather forecast and the differences in forecasted temperatures are often 2-3 degrees C. And everything with a horizon over 72 hours is just numerology. (OpenWeather showed -19C in early days of Feb just 2 days ago, today it is -2C). Now a model is just a model (I had some experience with industrial and financial models) so they are good at this and not so good at that. And they are recalculated and self-adjusted over time. I can understand. But from the user perspective there is huge difference between +1C tomorrow and -3C. Windy app is using 4 models and has nice graphical comparision of forecasts. * - What I mean here is that meteorologists have good understanding of processes but the numbers that we are getting could be as well random.
- LoSboccacc 8y agoIn Italy forecast are so unreliable they cannot predict rain in the evening from the morning. I don't know if it's because current climate change is throwing off models but short term forecast accuracy is terrible and I'm recently acutely aware of that since I switched to public transport for my commute.
- chewz 8y agoI know. I had been tending large garden (roses and lawn) in my friends house in Toscana this summer. And I had been looking for a rain everyday :-) and observing the change in forecasts and acctual result.
- mehrdadn 8y agoI've seen similar in California. Forecasts are really not always that accurate even within 24h.
- dantondwa 8y agoThis anecdotal, but I have observed, in my experience in Europe, that short-term forecasts are really inaccurate in countries like Belgium and Italy while, for example, they are really, really spot-on in mainland Poland. So, my guess is that it really depends on the kind of climate and, perhaps, on the impact of climate change in that area.
- OkGoDoIt 8y agoI’m sure it’s easier to predict weather in some places versus others, but in San Francisco I find the weather forecast to be wrong more often than not. I’m often told it’s currently sunny or raining when it’s the opposite. And forget about accurate high temperature predictions for tomorrow. At this point I don’t know why I even bother checking.
- deleted 8y ago[deleted]
- T3OU-736 8y agoIntriguing. Barely a mention (buried and oblique) that there are different weather models, and almost no discussion about relative accuracy or the reasons for the difference. Especially contrasting with the last paragraph being explicitly "Rah rah America" with the fact that the US NWS' weather models are less accurate than the European ones (hurricane Sandy was a huge wake-up call)
- brootstrap 8y agoThey also dont even reference any USA models in the article. The GFS was also showing this big cold snap, not just the euro!
- voyager2 8y agoI use the forecast put out by weather.gov that's supposedly tailored to the square mile because it gets the 12 hour forecast right about 40% of the time. The others are worse. Of course, when they say "chance of precipitation is 80%, less than an inch possible" and it doesn't rain, the forecast is semantically "correct." Like the El Nino impact on the SE US, where they forecast a 50% chance of drier colder weather and a 50% chance of warmer wetter weather, it's nearly impossible to be wrong. Maybe this is the sort of obfuscatory probabilistic forecast Mr. Meyer is counting as "accurate."
- kryogen1c 8y agoNo doubt. That's like saying horoscopes and fortune-tellers are stunningly accurate: "a positive opportunity will present itself to you today - you only have to open the door" "you are holding a secret pain that is preventing you from moving on. Find peace and let go"
- maaaats 8y ago> it gets the 12 hour forecast right about 40% of the time Where are these figures from? Your emotions, or something scientifically rigid? If the former, having this discussion is meaningless.
- deleted 8y ago[deleted]
- voyager2 8y ago"chance of precipitation is 80%, less than an inch possible" How would you determine, in a scientifically rigid manner, the limits on conditions which would validate that forecast as "right?" Or the inverse. What conditions would invalidate it as "not right?"
- scott_s 8y agoIn a top-level comment upthread, jacques_chester posted a link to an overview of forecast verification methods: http://www.cawcr.gov.au/projects/verification/ http://www.cawcr.gov.au/projects/verification/
- stunningly 8y agoThe actual research this is based on is: "The Quiet Revolution of Numerical Weather Prediction" Bauer, Thorpe, Brunet, 2005. "Stunningly Accurate" means that 7-day forecasts are now at the lower boundary of being considered "useful" so the bar is not being set very high here. Still not a lot to quell the skepticism that some reasonable people have about the ability of scientists to accurately predict weather decades in the future.
- organsnyder 8y agoWeather ≠ climate.
- nonsequitter 8y agoright. climate is a more complex system. more variables. more unknowns. exponentially larger prediction area. unknown base states. so it should be much easier to predict right?
- jacques_chester 8y agoClimatology works at a different granularity in time and space from meterology. You can abstract away a lot of detail in climate models and still come out with useful predictions (the article has an example). You can include items like Antarctic sheet melt and Tundra methane release that has almost zero 72-hour effect but will matter deeply in 5, 50, 200 years.
- Majromax 8y ago> so it should be much easier to predict right? Yes, because the goals of the forecast are different. A weather forecast seeks to predict a future position within the phase space of the system; a climate forecast seeks to predict the overall shape of that phase space. "It will be 1C warmer in February on average" is a useless prediction if I'm deciding whether or not to wear a heavy coat tomorrow, since day-by-day variability swamps that average. But it is a very useful prediction if I'm designing infrastructure that needs to last 50 years.
- 8y ago
- ancorevard 8y agoNo, both our weather forecasting and climate model forecasting are still very very weak and poorly understood. Predicting the future is still hard for us humans.
- amdavidson 8y agoSources?
- ljcn 8y agoShout out to Climendo. I use the android app and it gives me a simple comparison of 4-5 weather forecasts, an "average" forecast, and a "certainty" (a measure of consensus). Obviously the average of the ensemble averages isn't as good as having the underlying ensembles themselves, but it's nice to see days when the forecasts agree and days when they have no idea!
- jacques_chester 8y agoMany folks, when hearing forecasts have improved, will disagree. They can think of many times when the forecast was wrong, perhaps hilariously or disruptively so. This is textbook availability bias. You overestimate the failure rate because the failures were memorable, especially the major failures. But the far more frequent accurate predictions are not recalled, because they don't leave as much of an emotional impression. For the same reason folks regularly overestimate crime rates, deaths from terrorism or rare diseases. Meteorology has an entire subfield devoted to studying the quality of forecasts[0]. Before you bandy about numbers and anecdotes, stop and tell me what measure you are using. Is it percentage of degrees centigrade? Well you can't, degrees centigrade is an interval measure, not a ratio measure. If you use Kelvins, which has a mathematically meaningful zero, the percentage accuracy is suddenly very good. How do you count near misses of very intense weather? Direct hits by systems that were less intense than expected? How do you account for systems with very gradual gradients over very wide areas? How do you account for being early by an hour or late by an hour, but nailing the storm surge? How do you score for confidence? What's your rule for weighting false alarms? How important is mean error vs absolute error vs variance, and why? Solve these and dozens of other problems of describing "accuracy" and weather forecasters might take you seriously. But until then it's probably worth accepting that they are the most effective profession of their kind and that we have a lot we can learn from them. [0] http://www.cawcr.gov.au/projects/verification/ http://www.cawcr.gov.au/projects/verification/
- grawprog 8y agoI worked outside every day for 4 years at least. Weather forecasts are so unreliable I stopped listening. I had better luck trying to figure out if i'd need rain gear in a day by just waking up and looking out the window in the morning than looking up or listening to a weather forecast. You really start to notice how wrong they are when you spend every day outside. I don't notice any more working inside again. But when you rely on weather forecasts everyday to figure out how miserable you're going to be in a day...you really notice..they might as well just be making things up half the time.
- bainsfather 8y ago
- msravi 8y agoAnyone who is a weather buff should try meteogram (https://play.google.com/store/apps/details?id=com.cloud3squared.meteogram https://play.google.com/store/apps/details?id=com.cloud3squa...). You can plot a huge host of parameters (temperature, dew point, pressure, humidity, precipitation, wind speed/direction, sun/moon azimuth/elevation, etc.) over time, and the insights are very revealing. You can also choose multiple data sources, and it even has options to display METAR data.
- galfarragem 8y agoBest forecasts that I know (accurate enough to people come and ask me): https://www.windguru.cz/ https://www.windguru.cz/ Notes: - Only the GFS27KM is reliable on free version and within next 48-72h. - Temperatures are always conservative on extremes. When it says 37C, expect 40C. When 2C expect 0C.
- bsbechtel 8y agoI only see forecast errors for hurricanes listed as the cited data. Maybe I missed the other cited sources for data measuring forecast accuracy, but hurricane forecast accuracy, which is a storm that covers hundreds of square kilometers, doesn't seem like enough data to justify making the general claim 'modern weather forecasts' are stunningly accurate.
- sleepysysadmin 8y agoThe recent snow storm in my area, 4 days in advance they were predicting 30cm of snow. 3.5 days in advance were 25cm of now. 3 days in advanced 15cm of snow. 2 days in advanced 5-10cm of snow. 1 day in advance 15cm of snow. We got about 10cm of snow. Sorry but that's stunningly inaccurate.
- RivieraKid 8y agoWhich model? Try ECMWF on windy.com, that's usually the most accurate one for long-term.
- usermac 8y agoWow, what a nice looking weather website. Thanks. Didn't know about it.
- AuthorizedCust 8y agoWhile that's an anecdote, it's true too often for me to feel that forecasts are "stunningly accurate". That label implies near-perfection, which is laughable.
- simonh 8y ago4 days in advance they correctly predicted you would get snow and that it would be on the order of tens of centimeters thick. That's really good. Over the intervening days they revised their estimate down and the snowfall was eventually lower than the initial estimate so the accuracy improved. Their final estimate was again correct that you did get snow, which is the key prediction, and they even got the depth at your precise location right to within 33%. That's fantastic, and far better than was possible for the vast majority of my lifetime. Also, the fact that their predictions were all rounded to the nearest 5cm should give you a clue at the expected accuracy and granularity of the final prediction. Missing the target by only one 'unit' of measure is pretty decent.
- scott_s 8y agoThere's also the fact that predicting amount of snow is particularly difficult because the same amount of water will yield vastly different snowfalls with single-degree deviations of the temperature.
- libso 8y agoWhat's missing in most of the weather services is the recent history forecast vs observation.
- littleredstar 8y agoAs an amateur astronomer/astrophotographer for the past 25+ years I've relied on long to short term forecasts. Will it be clear for an event I want to see? I can certainly agree the models have improved and are pretty good. Much to my dislike on occasion such as the recent lunar eclipse. I was clouded out, that looked likely days ahead of time. One has to appreciate the complexity of modeling such a large and dynamic system that the atmosphere is! There are cases where forecasting is more difficult. Certainly getting the temperature correct within a degree or two is one case. Another issue is geography. I'm in middle of of USA and there is significant amount of data collected over the continental US as systems approach me. For those on the west coast I can see where forecasting is more challenging since there is far less data available to input into models (current atmosphere state 100s of kilometers out over the ocean). I'd suspect some European countries experience same situation, those further inland benefit from increased modelling data. Reading the comments here I'm a bit surprised at how many quibble over slight details. The improvements over the past decades in forecasting models and the supercomputers that crunch the data has been significant. In most cases, like recent cold temperatures and snow fall amounts, models converge on a good solution as the event nears. This is consistent with idea that better data input yields better data out.
- brootstrap 8y agoThe system is complex beyond our comprehension. If we really wanted to model weather and climate better we need to know more things. Things like how much cow farts are there? I would be happy to build a system to ingest cow fart obs and feed them into the numerical models. FPS farts per sec yo
- brootstrap 8y agoJust a little knowledge to drop, as a bachelor degree meteorologist and also coder / HN'er. Dont use your built in phone app for forecasts. Dont expect hour by hour precision (maybe for the next few hours sure, but not 2,3,4,5 days out). Trust nobody expect the trained professionals at NWS. These people look at ALL the models, they watch things like a hawk. I work with some of these nerds and it's crazy. They are like 'oh jimbob did you see the latest GFS kicking out the low up into canada? oh yeah doug that is crazy, but the euro says blah blah and NAM says blahblah... Their job is to literally make a forecast, for the same area, every day. Some people do it for years and years! Think of the experience, wisdom, little tricks and tips etc. Just go to weather.gov, look at it for 2 minutes. Read the foreacst discussion if you want to get your details.
- pxlpshr 8y agoI find Dark Sky to be the best forecasting tool for weather within the hour. It's almost always ahead of all the other apps in terms of the latest forecast.
- wenc 8y agoI bought the app because of its hyperlocal forecasting, but it's been known to predict precipitation where there's none, and vice versa. I wonder if it does better in some geographies than others (e.g. high pressure system areas where things are more stable)
- brootstrap 8y agohyperlocal is a joke, sorry to say it. Just because you can downscale your grid to a very small number doesnt mean good data. It just means you can do statistics and mathy stuff to interpolate. Everyone forecasts better in stable times such as a strong high pressure ridge. The tricky part is the edge areas between air masses, the transition zones. This is where all the juicy weather actually happens and it is the hardest to model
- Groxx 8y ago
- nabla9 8y ago> Meteorologists are increasingly uniting weather models and climate models, allowing them to project the general contours of a season as it begins. Weather and climate models are gradually converging and both are getting incredibly good. They work even in astronomy. You take a climate model, set the parameters for Mars or some exoplanets and what you get is relatively good Mars climate model or good principled guess of of what the climate in tidal locked planet around ultra-cool red dwarf star is (TRAPPIST-1).
- gruez 8y agoI skimmed this article and the linked sciencemag article and they seem to talk about wide scale weather events (eg. hurricanes), rather than the typical things that people look for in forecasts (yes/no rain, min/max temperature). A freakonomics article from 2008 found that at least for precipitation forecasts, weather forecasts don't fare much better than a simple probabilistic model. Has forecasts like these improved in accuracy?
- ggm 8y agoBack in the seventies and eighties there were four sources of impetus for improvement in highly parallel supercomputing. Military/Nuclear, high energy physics, oil and gas exploration (seismic analysis) and weather. The weather people were the nicest. They could talk to almost anyone about their work! I remember somebody in csiro talking to me about models getting accurate at the 1km square granular scale for a day. I think we're well beyond that for both cell size and duration now. Everyone loves to talk about the weather and Bob Dylan was wrong about not needing a weatherman to know which way the wind blows
- mh8h 8y agoIf you're looking for a graph that shows more than a projected minimum/maximum for every day, take a look at Foreca's 15-day forecast page [0]. It shows percentile lines for the forecasted minimum and maximum, which give a much better idea of what to expect. It also forecasts global vs. local precipitation. Unfortunately it is only available in Finnish. [0] https://www.foreca.fi/Canada/Vancouver/15vrk https://www.foreca.fi/Canada/Vancouver/15vrk Disclaimer: I used to worked for MSN Weather, where we used Foreca's feed as the source for our weather data.