I understand that weather on TV can’t be hyperlocally accurate. But a weather app on my phone has my exact GPS coordinates. Why can’t it tell me exactly when a rain cloud will be passing over my location?

It’s gotten to the point where I just use precipitation maps to figure out my rain chances for the day.

The hourly forecast is mostly useless because it’s not a chance % but a % of the area that will be raining.

  • viking@infosec.pub
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    2 months ago

    Weather apps don’t do real time analytics, but show you the forecast some nearby weather station has calculated. Whether that’s based on current data or a couple hours ago depends on the exact provider they use. And hardly anyone of those are done by actual humans, it’s aggregated statistics.

    If you look at precipitation maps, you are doing that forecast by yourself based on cloud movements and local knowledge, something no machine-generated forecast can do as good.

    Plus, there’s usually one weather station covering a large area, so hyperaccurate predictions would have to be made just for you - which simply costs to much.

    • halcyoncmdr@lemmy.world
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      2 months ago

      Nearby is so highly dependent on where exactly those are located, and what they’re connected to (some are handled by local volunteers that have hardware that reports periodically as opposed to being operated by an agency directly). Various apps don’t all connect to the same data sources.

      Official reporting locations may not actually be close to you and weather can be highly localized. A mile can make a massive difference in weather in some regions, and the official recording location for the city is 10 miles away.

      • BearOfaTime@lemm.ee
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        2 months ago

        Even very close data stations are limited. I regularly get incorrect rainstorm notifications from data gathered from a couple miles away.

        • halcyoncmdr@lemmy.world
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          2 months ago

          Sma here. I have a buddy that’s a half mile away and we regularly don’t have the same rain. It’ll be pouring here and dry as a bone there.

          • acetanilide@lemmy.world
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            2 months ago

            I once experienced a storm where, for a very brief time, my front yard was experiencing a torrential downpour and my back yard was dry as a bone.

            My house was not that big - maybe 1700-1800sq ft - and our lot size was less than a quarter acre. Blew my mind. (Obviously storms have edges. It was still weird.)

          • Hellinabucket@lemmy.world
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            2 months ago

            I had family from out of town calling me once because the nstional news was reporting the entire area was hit with heavy storms and tornados. The city isn’t even more then 15 minutes down the interstate, but we didn’t get a single drop of rain.

    • Etterra@lemmy.world
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      2 months ago

      Especially because in some places, with more or less frequency, it can be raining somewhere and not raining a mile from there, and randomly just interspersed around randomly. I hear Florida is exactly like that and it makes them extremely hostile towards meteorologists.

  • CountVon@sh.itjust.works
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    2 months ago

    MinuteCast from AccuWeather does exactly this. It looks at your location, looks at radar data for storm systems approaching your location, and estimates when precipitation will start at your location and how intense it will be. It’s generally pretty accurate, with some limitations. It seems to be pretty good for consistent rainstorms but it can get tripped up by pop-up thunderstorms, where the radar track can go suddenly from no rain to downpour. It doesn’t make predictions more then 2-3 hours out because past that timeframe it’s not easy to predict if weather will continue on its current track or change direction. Even with the limitations, I use it all the time. Mostly to tell if I should take the dogs out right away, or if I should wait an hour or two.

  • dan1101@lemm.ee
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    2 months ago

    Look at a weather map with animated radar overlay. You will often see precipitation approaching and can predict how soon based on its speed and heading.

  • linearchaos@lemmy.world
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    2 months ago

    Darksky could do it back in the day more or less. you’d get messages that it would rain in about 15 minutes and stop in the next 30.

    Thing is, precep maps don’t work everywhere. You’re probably in a location like me where a thick front rolling through will almost always bring rain. If you get into warmer tropical climates, rainclouds will just poof out of nowhere and drop rain on your ass while other crazy fronts will pass over with nothing but some dark clouds.

        • Curious Canid@lemmy.ca
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          2 months ago

          Oh, yeah. Not only did they take it away from all Android users, they also killed the API that let other apps access it. I wrote an open-source tool that made Dark Sky data available to Wear OS watch faces. It worked beautifully for several years, until Apple killed it.

          The worst of it is that was my second attempt. An earlier version of the same tool worked with Weather Underground data. Then IBM bought it, changed the API completely, and priced it so that only business could afford it.

          I haven’t had the heart to try a third time.

          Sorry, every once in a while I’m overcome with the need to whine about it.

          • Talaraine@fedia.io
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            2 months ago

            I can’t really describe to you how angry I was when that shit went through. Like… I knew it was ridiculous to get so angry but, I LOVED THAT FREAKING APP.

  • Kelly@lemmy.world
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    2 months ago

    The hourly forecast is mostly useless because it’s not a chance % but a % of the area that will be raining.

    Unless your precise location is a statistical outlier these will be the same thing?

  • givesomefucks@lemmy.world
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    2 months ago

    But a weather app on my phone has my exact GPS coordinates. Why can’t it tell me exactly when a rain cloud will be passing over my location?

    Because they’ve never been able to do that…

    When they say “50% chance of rain”, it doesn’t meant there’s a 50/50 chance it rains where you’re located

    It’s that for the broadcast area, about half is gonna get rain.

      • WolfLink@sh.itjust.works
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        2 months ago

        Key word “in the given forecast area”.

        The statement “there’s a 40% chance of rain at any given point at any given time in the forecast area/period” is an average over both area and time.

        Many different actual distributions of rain could result in that average, including a 100% chance of it raining 100% of the time in 40% of the are or a 40% chance of it raining in 100% of the time in 100% of the area, and a 100% chance of it raining 40% of the time in 100% of the area. Real distributions are typically messier than that.

        • linearchaos@lemmy.world
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          2 months ago

          yeah, never mind the references in the article where they pointed out the evidence for their conclusions. :P

          • kitnaht@lemmy.world
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            2 months ago

            Reading Snopes will give you plenty. Read the articles - and a lot of them use weasel-wording to push the result they want.

            I don’t have the exact article on hand at the moment, but an example would be someone claiming that clear-cutting 1000 acres of trees would destroy [X]^3 of CO2 reduction; and then Snopes will “fact check” it by saying they aren’t cutting down 1000 acres of trees this year. Often times they’ll ‘debunk’ something that sounds like the claim, but isn’t the actual claim.

    • criticon@lemmy.ca
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      2 months ago

      No it doesn’t, it means that under those conditions, about 50% of the times it has rained in that area

    • Pasta Dental@sh.itjust.works
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      2 months ago

      It’s that for the broadcast area, about half is gonna get rain.

      Isn’t that virtually the same thing as a 50% chance of rain at my position though?

  • atrielienz@lemmy.world
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    2 months ago

    For one thing, there’s two competing weather services providing the data to countless apps in the US and one of them has more money to throw around than the other.

    The weather channel has better weather predictions overall than Apple’s own weather app, as rated by Forecastadvisor.com, but is not as accurate as Accuweather is although it’s used in more apps.

    Weather is about tracking and predictions. It’s never going to be completely 100% correct. But taking a hodgepodge of information from several prediction services means you’re more likely to be less accurate overall despite what people may think.

    • tyler@programming.dev
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      2 months ago

      All of those weather services just pull data from NOAA. There’s no competition, besides making up stuff beyond what NOAA predicts.

      • atrielienz@lemmy.world
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        2 months ago

        NOAA is one, the US armed Forces is the other. Not including info provided from other weather agencies outside the US.

  • edric@lemm.ee
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    2 months ago

    Weather Underground allows you to filter down to your zip code. Not accurate down to your exact vicinity, but better than the weather forecast for your entire city.

  • Audalin@lemmy.world
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    2 months ago

    Because we have tons of ground-level sensors, but not a lot in the upper layers of the atmosphere, I think?

    Why is this important? Weather processes are usually modelled as a set of differential equations, and you want to know the border conditions in order to solve them and obtain the state of the entire atmosphere. The atmosphere has two boundaries: the lower, which is the planet’s surface, and the upper, which is where the atmosphere ends. And since we don’t seem to have a lot of data from the upper layers, it reduces the quality of all predictions.