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Modern Weather Forecasts Are Stunningly Accurate

theatlantic.com

71–80 of 120 posts

Re: Modern Weather Forecasts Are Stunningly Accurate

#71

> 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…

Floridian. 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.

Re: Modern Weather Forecasts Are Stunningly Accurate

#72
post #20

Earlier quoted context omitted.

But from the user perspective there is huge difference between +1C tomorrow and -3C. Really? I'd read those both as "near freezing, going to need a decent coat".

+1 means that the packed snow is going to melt on top and then probably re-freeze, making everything super slippery. So I need to remove as much snow from the paths as possible and spread sand, and remind the kids to be careful. -3 means relax.

It is unfortunate for us that even tiny prediction misses around the freezing point have drastic differences in our experience. But it does not change that they are tiny prediction misses. We take for granted how good they have become.

Re: Modern Weather Forecasts Are Stunningly Accurate

#73

Many 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 impre…

I 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 wh…

Similar experience in the uk, in terms of whether it will rain or not. 3 hour, 6 hour etc forecasts are of little use - no better than looking out the window. Meanwhile wind speed and temperature seem ok on that timescale, but are (usually) less important to me than precipitation.

It depends a lot on what part of the world you are in - I think that the uk is particularly hard to forecast.

Re: Modern Weather Forecasts Are Stunningly Accurate

#74
post #66

The 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.

4 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 you…

There'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.

Re: Modern Weather Forecasts Are Stunningly Accurate

#75

Many 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 impre…

I 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 wh…

Hmmm. If you are needing down to the minute accurate timing of when rain is going to start & stop, sure nobody can predict that, for every location in the USA, all the time. I have to question where you are getting your weather forecast information??? I am a bachelor degree meteorologist, I dont use any apps that try to be 'hyper local' (omg i hate that word, it is the weather version of AI/ML hype). Just go to the government site www.weather.gov

We can't predict exactly when it will rain, but we can get daily trends pretty good for 3-5 days out. This means you are five days ahead of the weather. You cant know "it will rain from 5:00am to 9:30am on february 4th, 2019". But you can know if we have a synoptic scale system that is moving through your area on that day, and know if there is a probability of rain.

Where do you work everyday outside? i would be happy to give you a 5 - 10 day forecast right now actually and can tell you it will be good. I am supposed to be writing some tests and documentation but i can drop some WX knowledge if you need.

Re: Modern Weather Forecasts Are Stunningly Accurate

#76

Intriguing. 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)

They also dont even reference any USA models in the article. The GFS was also showing this big cold snap, not just the euro!

Re: Modern Weather Forecasts Are Stunningly Accurate

#77
post #10

Just 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 s…

oh man - you want to know something funny. At my startup we had a guy hacker in a random weather generator to use in our models. I was like WTF Man!

The numbers you are getting are not random. Sure the models are chaotic and non-linear, but still it's giving you hints at potential patterns, especially at long range time scales. People need to understand that wx forecasts, especially 3+ days out, should be read as guidelines for what is LIKELY to happen. Say that GFS predicts two inches of rain for your city over the next week as a wave comes through. What if the next model run shifts that blob of rainfall 25miles north? In the model terms, global terms, 25miles is nothing. But for you that is the difference between dry & soaked , and you think the model sucks.

Re: Modern Weather Forecasts Are Stunningly Accurate

#78

Many 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 impre…

Validating the wx is extremely hard. For instance, if you make a forecast, what do you use as the 'truth'? A weather station? Trust me, I've worked with plenty of station data, and it is trash. So now you are comparing a weather forecast against some suspect trash validation set. Nobody knows!

The fact is, predictions will keep getting gradually better, more high res. But the fact our atmosphere & earth system is insanely complex. The system is chaotic so tiny small changes in each model run produce different results... We have code to represent some basic physics but still dont understand many of the important things. We still dont know exactly the rain process & snow formation process. We are trying to pinpoint the exact moment when dust & water vapor magically form into a cloud droplet so we can better describe the rain process. THEN we have to translate all of this insane math and physics into code.

Re: Modern Weather Forecasts Are Stunningly Accurate

#79
As 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.

Re: Modern Weather Forecasts Are Stunningly Accurate

#80

Earlier quoted context omitted.

I 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 wh…

Hmmm. If you are needing down to the minute accurate timing of when rain is going to start & stop, sure nobody can predict that, for every location in the USA, all the time. I have to question where you are getting your weather forecast information??? I am a bachelor degree meteorologist, I dont use any apps that try to be 'hyper local' (omg i hate that word, it is the weather version of AI/ML hype). Just go to the g…

I get the feeling that this "hyper-local" mentality contributed to NYC and surrounding areas being caught flat-footed by the first-of-season snowfall at the end of last year. I have little understanding of meteorology, but it was clear, just from the forecast maps, that a small change in the location and timing of the rain/snow line would make a big difference to the outcome, and that something more than was forecast was a distinct possibility.

As with many things, having a little understanding of the big picture can help you get more out of weather forecasts.

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