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How good is weather prediction for other people? Is it actually accurate for you? Are even the current conditions accurate for you? I use Weather Underground, a

How good is weather prediction for other people? Is it actually accurate for you? Are even the current conditions accurate for you? I use Weather Underground, and a few weeks ago in the Bay, here are just a couple of the things I remember observing (out of the many wrong predictions): (1) One afternoon I was told there would be rain in 5-6 hours, then a couple hours I was told there would be none. (2) I started getting soaked while walking outside, and I checked the current conditions and was informed it is in fact not raining and there is no upcoming rain either. These were despite the facts that the weather stations were < 1 mile away for me and the conditions persisted for a fair bit (i.e. it wasn't just a random 2-minute shower).

baddox 8y ago
Parts of the Bay Area are pretty famous for having microclimates. I wouldn’t really use traditional weather reports for determining if it’s currently raining right here, but I find them accurate enough for determining if I need to carry my rain jacket or umbrella for the day.
- mehrdadn 8y ago
  This wasn't a microclimate issue. I'm pretty darn sure the conditions at the station simply could not have been so radically different. And re: forecasts, if I had just looked at the weather to see if I needed an umbrella that evening I would've concluded "yes" if I had looked at 2pm and "no" if I looked at 3pm. Sometimes they do get it right, but other times they're just literally useless.
  - baddox 8y ago
    The point of having the umbrella with you for the day is so that when you walk out the door and it’s raining you can open the umbrella.
    - mehrdadn 8y ago
      Yes? Not sure how this is a reply to the comment...
kwelstr 8y ago
Similar experience here in South Florida, the two weather apps I am currently using not always agree on the next day weather and often are wrong on the same day weather forecast. It seems to me that there was better accuracy a couple of years ago and somehow they have degraded. I am puzzled :/
jetrink 8y ago
I pay close attention to precipitation forecasts due to the nature of my job. In the midwest, National Weather Service forecasts up to seven days out are reliable and useful. If the NWS says there will be a rainstorm in a week, there usually is one and vice versa. The quantitative aspect of the forecasts is less accurate. It is common to see a small storm become a large one or for a scary storm to fizzle. This is the page that I check every morning: https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml
- mehrdadn 8y ago
  Oh interesting! Thanks for sharing that.
minimalist 8y ago
If you are in the United States, you may be interested in the scientific forecaster discussions produced by your local NWS office. They provide more insight into forecast confidence and general regional dynamics. Theyre produced several times a day and are often quite fun to read. Its amazing how far we have come in weather prediction. A few decades ago, 5-day forecasts did not exist and now we get 10-day forecasts that are reliable enough that we take it for granted. In my experience, nothing beats getting the forecast straight from the horses mouth (NWS that is). Some companies are notorious for producing 30+ day forecasts, which cant have any meaningful levels of skill. I never understood why NOAA/NWS didnt just create their own mobile app. I use Wx[0], which parses NWS data directly and can be found on f-droid. [0] https://gitlab.com/joshua.tee/wx https://gitlab.com/joshua.tee/wx
- mehrdadn 8y ago
  Interesting... do you see the NWS forecasts being more accurate then Weather.com/Weather Underground? It always felt to me like the former was (basically/effectively) a low-pass-filtered version of the latter, not actually any more accurate, but I have't really compared them that carefully.
  - Donald 8y ago
    The NWS produces expert commentary (aka "forecaster's discussion") that can explain the deviations from forecasted weather. For example, there is a stalled weak cold front over the US right now. Many areas are getting variants of "Though not currently included in our forecast, very minor rain chances could return on Wednesday with models indicating some eastward movement of the ridge and an increase in PWAT values" based on the underlying uncertainty behind where exactly this frontal system will stall out.
- maxerickson 8y ago
  Corruption, or so. There was almost legislation to stop them from distributing data to the public directly, because then companies can make more money doing it.
- feedbeef 8y ago
zdragnar 8y ago
Upper midwest here. Hourly predictions are accurate more often than not, and a few days out is chancey. Big storms are often exaggerated, though I suspect that's because the risk of flooding, ice and other hazardous travel conditions are serious enough to be overly cautious. We had predictions for major snowfalls a few times, and every time was completely overblown, and then one hit exactly as predicted. Definitely glad I wasn't on the road that evening.
- mehrdadn 8y ago
  Ahh yeah, you guys probably get a lot more extremes. :)
mannykannot 8y ago
I do a number of outdoor activities and I think forecasting has become very reliable, with the caveat that precise precipitation amounts and timing can vary over a short distance. If you are concerned about rain in the next couple of hours, take a look at the radar maps, and see if the situation is shaping up as predicted.
- mehrdadn 8y ago
  Yeah the amount is secondary. I don't really have a good feel for 0.01 inches vs. 0.1 inches anyway (both seem small and then I constantly get surprised). Trouble is when they literally say no chance of rain and then I get soaked, or when they say it'll rain and there's not a single drop.
  - deleted 8y ago
    [deleted]
CarVac 8y ago
If you look at the models themselves you can look several days out and get an idea of what could happen. https://mag.ncep.noaa.gov/model-guidance-model-area.php https://mag.ncep.noaa.gov/model-guidance-model-area.php Select GFS (Global Forecasting System, the usual model) and NAMER (North America), then Precip P06 (six-hour precipitation accumulation), and then Loop All. Over time, you learn the behavior of the models; for example the GFS's longer-range predictions tend to overestimate peak rainfall from super heavy storms (it'll predict three inches and we'll get one). It's not as convenient as Wunderground but it's data straight from the source. Other occasionally useful models are the NAM (shorter range and limited to North America) and the HRRR (high time resolution but very short range).
ravedave5 8y ago
Besides microclimites, which are a whole other discussion, predictions vary per service. It looks like AccuWeather has a 2% better rating for San Francisco, it's not much but it's something. https://www.forecastadvisor.com/California/SanFrancisco/94128/ https://www.forecastadvisor.com/California/SanFrancisco/9412... but compared to a smaller city also with microclimates on a large body of water the prediction for San Fran is 15% better - https://www.forecastadvisor.com/Minnesota/Duluth/55811/ https://www.forecastadvisor.com/Minnesota/Duluth/55811/
- freehunter 8y ago
  That's the first time I've seen that site, and for my city it's kind of frustrating if it's true. The Weather Channel rates the best (by far) compared to my preferred app, but I find The Weather Channel app to be an awful user experience for how I want to see weather presented to me.
  - myama 8y ago
    The Weather.com data is sold to Google, Facebook and many others. Perhaps you find a better user experience on those platforms?
LoSboccacc 8y ago
here in italy is wildly inaccurate. medium and long term stability/instability trend holds, but day by day or hour by hour prediction are almost completely worthless.
hadlock 8y ago
My experience living in Dallas, Texas, which has some 1500 miles of accurate weather data as systems come across the north american continent from west to east.... usually the 10 day weather forecast was accurate to within 4 hours. This is really helpful for planning sailing trips, etc. Usually three days out the weather prediction is accurate to within 30 minutes. As for the California SF Bay area, weather prediction is mostly useless, day to day weather prediction is wildly inaccurate. I think just on Friday there was a prediction that we were going to have a bunch of fog through Tuesday, and it was clear the next day. Wild storms will be predicted, and then never appear, and other times weather that was going to hit Oregon smashes in to the bay for three days. Many times we've gone out sailing expecting calm forecasted weather (Mother's Day 2016) and got 25mph winds and other times we went out expecting forecasted 15mph winds and it was closer to 6-8mph. My guess is that the lack of HD weather radar in the pacific and the complex topology of the coastal areas and the bay, and also the chaotic interaction between ocean and inland weather systems make for a much more challenging forecasting system than doing forecasting of the plains states. The unique geography of the golden gate being a venturi tube between the low pressure 55F/13C pacific ocean marine layer and the high pressure 95F/35c central valley some forty miles inland creates what the local slang describes as "the wind machine".
HALtheWise 8y ago
I highly recommend Darksky[1], or one of the copycat services like the AccuWeather Minutecast. They use computer vision based approaches processing radar fused with conventional forecasting, and do quite a good job. I believe that some other "hourly" forecasts are still published at the beginning of the day, rather than continually updated. [1] https://darksky.net/ https://darksky.net/

baddox 8y ago

Parts of the Bay Area are pretty famous for having microclimates. I wouldn’t really use traditional weather reports for determining if it’s currently raining right here, but I find them accurate enough for determining if I need to carry my rain jacket or umbrella for the day.

mehrdadn 8y ago
This wasn't a microclimate issue. I'm pretty darn sure the conditions at the station simply could not have been so radically different. And re: forecasts, if I had just looked at the weather to see if I needed an umbrella that evening I would've concluded "yes" if I had looked at 2pm and "no" if I looked at 3pm. Sometimes they do get it right, but other times they're just literally useless.
- baddox 8y ago
  The point of having the umbrella with you for the day is so that when you walk out the door and it’s raining you can open the umbrella.
  - mehrdadn 8y ago
    Yes? Not sure how this is a reply to the comment...

kwelstr 8y ago

Similar experience here in South Florida, the two weather apps I am currently using not always agree on the next day weather and often are wrong on the same day weather forecast. It seems to me that there was better accuracy a couple of years ago and somehow they have degraded. I am puzzled :/

jetrink 8y ago

I pay close attention to precipitation forecasts due to the nature of my job. In the midwest, National Weather Service forecasts up to seven days out are reliable and useful. If the NWS says there will be a rainstorm in a week, there usually is one and vice versa. The quantitative aspect of the forecasts is less accurate. It is common to see a small storm become a large one or for a scary storm to fizzle. This is the page that I check every morning: https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml

mehrdadn 8y ago
Oh interesting! Thanks for sharing that.

minimalist 8y ago

If you are in the United States, you may be interested in the scientific forecaster discussions produced by your local NWS office. They provide more insight into forecast confidence and general regional dynamics. Theyre produced several times a day and are often quite fun to read. Its amazing how far we have come in weather prediction. A few decades ago, 5-day forecasts did not exist and now we get 10-day forecasts that are reliable enough that we take it for granted. In my experience, nothing beats getting the forecast straight from the horses mouth (NWS that is). Some companies are notorious for producing 30+ day forecasts, which cant have any meaningful levels of skill. I never understood why NOAA/NWS didnt just create their own mobile app. I use Wx[0], which parses NWS data directly and can be found on f-droid. [0] https://gitlab.com/joshua.tee/wx https://gitlab.com/joshua.tee/wx

mehrdadn 8y ago
Interesting... do you see the NWS forecasts being more accurate then Weather.com/Weather Underground? It always felt to me like the former was (basically/effectively) a low-pass-filtered version of the latter, not actually any more accurate, but I have't really compared them that carefully.
- Donald 8y ago
  The NWS produces expert commentary (aka "forecaster's discussion") that can explain the deviations from forecasted weather. For example, there is a stalled weak cold front over the US right now. Many areas are getting variants of "Though not currently included in our forecast, very minor rain chances could return on Wednesday with models indicating some eastward movement of the ridge and an increase in PWAT values" based on the underlying uncertainty behind where exactly this frontal system will stall out.
maxerickson 8y ago
Corruption, or so. There was almost legislation to stop them from distributing data to the public directly, because then companies can make more money doing it.
feedbeef 8y ago

zdragnar 8y ago

Upper midwest here. Hourly predictions are accurate more often than not, and a few days out is chancey. Big storms are often exaggerated, though I suspect that's because the risk of flooding, ice and other hazardous travel conditions are serious enough to be overly cautious. We had predictions for major snowfalls a few times, and every time was completely overblown, and then one hit exactly as predicted. Definitely glad I wasn't on the road that evening.

mehrdadn 8y ago
Ahh yeah, you guys probably get a lot more extremes. :)

mannykannot 8y ago

I do a number of outdoor activities and I think forecasting has become very reliable, with the caveat that precise precipitation amounts and timing can vary over a short distance. If you are concerned about rain in the next couple of hours, take a look at the radar maps, and see if the situation is shaping up as predicted.

mehrdadn 8y ago
Yeah the amount is secondary. I don't really have a good feel for 0.01 inches vs. 0.1 inches anyway (both seem small and then I constantly get surprised). Trouble is when they literally say no chance of rain and then I get soaked, or when they say it'll rain and there's not a single drop.
- deleted 8y ago
  [deleted]

CarVac 8y ago

If you look at the models themselves you can look several days out and get an idea of what could happen. https://mag.ncep.noaa.gov/model-guidance-model-area.php https://mag.ncep.noaa.gov/model-guidance-model-area.php Select GFS (Global Forecasting System, the usual model) and NAMER (North America), then Precip P06 (six-hour precipitation accumulation), and then Loop All. Over time, you learn the behavior of the models; for example the GFS's longer-range predictions tend to overestimate peak rainfall from super heavy storms (it'll predict three inches and we'll get one). It's not as convenient as Wunderground but it's data straight from the source. Other occasionally useful models are the NAM (shorter range and limited to North America) and the HRRR (high time resolution but very short range).

ravedave5 8y ago

Besides microclimites, which are a whole other discussion, predictions vary per service. It looks like AccuWeather has a 2% better rating for San Francisco, it's not much but it's something. https://www.forecastadvisor.com/California/SanFrancisco/94128/ https://www.forecastadvisor.com/California/SanFrancisco/9412... but compared to a smaller city also with microclimates on a large body of water the prediction for San Fran is 15% better - https://www.forecastadvisor.com/Minnesota/Duluth/55811/ https://www.forecastadvisor.com/Minnesota/Duluth/55811/

freehunter 8y ago
That's the first time I've seen that site, and for my city it's kind of frustrating if it's true. The Weather Channel rates the best (by far) compared to my preferred app, but I find The Weather Channel app to be an awful user experience for how I want to see weather presented to me.
- myama 8y ago
  The Weather.com data is sold to Google, Facebook and many others. Perhaps you find a better user experience on those platforms?

LoSboccacc 8y ago

here in italy is wildly inaccurate. medium and long term stability/instability trend holds, but day by day or hour by hour prediction are almost completely worthless.

hadlock 8y ago

My experience living in Dallas, Texas, which has some 1500 miles of accurate weather data as systems come across the north american continent from west to east.... usually the 10 day weather forecast was accurate to within 4 hours. This is really helpful for planning sailing trips, etc. Usually three days out the weather prediction is accurate to within 30 minutes. As for the California SF Bay area, weather prediction is mostly useless, day to day weather prediction is wildly inaccurate. I think just on Friday there was a prediction that we were going to have a bunch of fog through Tuesday, and it was clear the next day. Wild storms will be predicted, and then never appear, and other times weather that was going to hit Oregon smashes in to the bay for three days. Many times we've gone out sailing expecting calm forecasted weather (Mother's Day 2016) and got 25mph winds and other times we went out expecting forecasted 15mph winds and it was closer to 6-8mph. My guess is that the lack of HD weather radar in the pacific and the complex topology of the coastal areas and the bay, and also the chaotic interaction between ocean and inland weather systems make for a much more challenging forecasting system than doing forecasting of the plains states. The unique geography of the golden gate being a venturi tube between the low pressure 55F/13C pacific ocean marine layer and the high pressure 95F/35c central valley some forty miles inland creates what the local slang describes as "the wind machine".

HALtheWise 8y ago

I highly recommend Darksky[1], or one of the copycat services like the AccuWeather Minutecast. They use computer vision based approaches processing radar fused with conventional forecasting, and do quite a good job. I believe that some other "hourly" forecasts are still published at the beginning of the day, rather than continually updated. [1] https://darksky.net/ https://darksky.net/