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Modern Weather Forecasts Are Stunningly Accurate

theatlantic.com

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Re: Modern Weather Forecasts Are Stunningly Accurate

#91

Post by brootstrap »

mannykannot wrote: post #80
brootstrap wrote: post #75

Earlier quoted context omitted.

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…

Your last statement is the so true. An amateur forecaster can spend ten minutes looking at the some big picture (synoptic scale) weather and know regional trends (this part of country is dry, these guys are wet, humid etc). This would be a pressure & wind map, showing location of high/lows, maybe some 850mb moisture charts too... But you are painting broad strokes. All of these dumbos on HN want to know exactly when the rain is going to hit your exact location, or you have to be within 3 degrees C modeling the surface temperature of my street so i can either ride my bike or not. We just cant do that with the current science & computational landscape!

After you have the synoptic scale picture, then you zoom in on your target area and get specific if you want to. This local expertise is where you NWS office comes into play. You want the local forecast from these guys!

Re: Modern Weather Forecasts Are Stunningly Accurate

#92

Post by tropo »

jacques_chester wrote: post #46

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…

Often I can't even say for sure if the forecast is wrong or not.

For example, what is a 10% chance of rain at 10? That could mean 10% chance that rain will occur at some point from 10 to 11, 10% chance that it will be raining at a randomly selected point between 10 and 11, or 10% chance that it will continuously rain from 10 to 11. Also, it could be any of those three, except from 9:30 to 10:30. Also, it could be a 10% chance of raining at exactly 10.

So right there, I see 7 possible interpretations.

Add in a map, and we can apply those to an area. It may be a 10% chance of raining at some place within this region, but any one place gets a smaller chance. It may be a 10% chance everywhere in the region, but a 99% chance that some part of the region gets rain.

Re: Modern Weather Forecasts Are Stunningly Accurate

#93

Post by rbritton »

pxlpshr wrote: post #86
brootstrap wrote: post #81

Just 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 lik…

I 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.

It's pretty accurate here, when it works. I'd guess at least 40% of the time it states that the local radar is down and refuses to give that kind of forecast.

Re: Modern Weather Forecasts Are Stunningly Accurate

#94

Post by Majromax »

voyager2 wrote: post #63
Majromax wrote: post #62

Earlier quoted context omitted.

> I 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. Unfortunately, this is an example of false precision. The highest resolution numerical forecasts run by NOAA have a grid of about 3km, already coarser than your one-square-mile "tailored" output. The effective resolution of numerical weather models is also 2-3 tim…

If I move my forecast location a few hundred yards, my elevation changes rather drastically, changing the forecast. Elevation isn't a factor most forecasts even consider. Is it false precision to use elevation to tailor the forecast?

In that case, the interpolation includes a vertical component as well. You'll see the effects of the lapse rate (change in temperature with height).

That's great for you, but it means that your forecast (of [my elevation, my coordinates]) is not much more accurate than one for ([my elevation, my coordinates plus a few hundred yards]).

More technically: "surface" isn't a smooth variable when elevation changes quickly, but interpolation like that performed by weather.gov necessarily works on smooth fields. Applying post-facto elevation is great and worthwhile, but it doesn't improve the accuracy in a technical sense.

Re: Modern Weather Forecasts Are Stunningly Accurate

#95

Post by grawprog »

brootstrap wrote: post #75
grawprog wrote: post #65

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 don't work outside any more. But it would be more things like entire weeks of rain or sun forecast and instead would be the opposite all week. I could be sitting in the sun listening to someone on the local radio station using data from the local weather stations telling me it's raining. Or ya know, see it's raining in the forecast and open my door to a blizzard.

Re: Modern Weather Forecasts Are Stunningly Accurate

#96

Post by tspike »

kawfey wrote: post #87
brootstrap wrote: post #81

Just 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 lik…

One of the things I loved best about Wunderground was their prominent display of the textual SFD. Now it's gotten a lot more mainstream, and still have increasingly accurate forecasts, but the SFD link has been dropped from the forecast page for any particular area. Now my source is directly from NWS page, which is really nice since forecaster terms can be clicked to bring up a definition. https://forecast.weather.go…

You can still find a link to it on the 10-day tab, but they did hide it.

Re: Modern Weather Forecasts Are Stunningly Accurate

#97

Post by porpoisely »

jacques_chester wrote: post #46

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…

Certainly weather forecasts are generally more right than wrong, but for a science, you expect it to be closer to 100% correct than 80% correct.

We don't care if weather forecasters take us seriously. The weather forecasters should care whether we take them seriously.

For example, just the other day in NY, we had a forecast of light rain. We got a snow squall instead. That sure was fun.

People aren't complaining about a forecast of 80 degrees but it was 81 instead. It's those forecast that call for light rain and you get a nice fun snow squall.

Re: Modern Weather Forecasts Are Stunningly Accurate

#98

Post by kevin_thibedeau »

jacques_chester wrote: post #46

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…

If you live near where the jetstream boundary usually lies, forecasts are generally less accurate because small, less predictable shifts can have a large impact on daily weather.

Re: Modern Weather Forecasts Are Stunningly Accurate

#99

Post by noir_lord »

brootstrap wrote: post #81

Just 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 lik…

I get my weather straight from UK met page for that reason.

It has much more detail which helps as a cyclist, there is more than just average wind speed and temp.

Re: Modern Weather Forecasts Are Stunningly Accurate

#100

Post by twic »

kawfey wrote: post #87
brootstrap wrote: post #81

Just 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 lik…

One of the things I loved best about Wunderground was their prominent display of the textual SFD. Now it's gotten a lot more mainstream, and still have increasingly accurate forecasts, but the SFD link has been dropped from the forecast page for any particular area. Now my source is directly from NWS page, which is really nice since forecaster terms can be clicked to bring up a definition. https://forecast.weather.go…

I think Metcheck is the UK equivalent of this. To pick a few random page of turbo-nerdery (if you need a UK postcode to try, the National Museum of Computing is at MK3 6EB):

https://www.metcheck.com/WEATHER/ghx_charts.asp

https://www.metcheck.com/WEATHER/discussion.asp?DiscussionID...

https://www.metcheck.com/WEATHER/laundry_drying_times.asp

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