[HN Gopher] NOAA deploys new generation of AI-driven global weat...
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       NOAA deploys new generation of AI-driven global weather models
        
       Author : hnburnsy
       Score  : 144 points
       Date   : 2025-12-17 22:32 UTC (3 days ago)
        
 (HTM) web link (www.noaa.gov)
 (TXT) w3m dump (www.noaa.gov)
        
       | margalabargala wrote:
       | I am dearly hoping that they are using the current "AI" craze to
       | talk up the machine learning methods they have presumably been
       | using for a decade at this point, and not that they have actually
       | integrated an LLM into a weather model.
        
         | username223 wrote:
         | Same. I hope this was written by hardened greybeards who have
         | dedicated their lives to weather prediction and atmospheric
         | modeling, and have "weathered" a few funding cycles.
        
           | akdev1l wrote:
           | inb4 it's actually an intern maintaining a 3000+ line
           | markdown file
        
             | RHSeeger wrote:
             | I can see it now                   The following snippet
             | highlights the algorithm used to determine <thing>
             | ```fortran         .....
        
         | idontwantthis wrote:
         | Hopefully they weren't all forced out this year. The NOAA had
         | massive cuts.
        
           | trueismywork wrote:
           | NCAR is being dismantled as we speak.
        
             | derbOac wrote:
             | I suspect the names of those perpetrating this kind of
             | destruction will become synonymous with ignorance and
             | intellectual cowardice.
        
         | sigmar wrote:
         | Graphcast (the model this is based on) has been validated in
         | weather models for a while[1]. It uses transformers, much like
         | LLMs. Transformers are really impressive at modeling a variety
         | of things and have become very common throughout a lot of ML
         | models, there's no reason to besmirch these methods as
         | "integrating an LLM into a weather model"
         | 
         | [1] https://github.com/google-deepmind/graphcast
        
           | lynndotpy wrote:
           | A lot of shiny new "AI" features being shipped are language
           | models being placed where they don't belong. It's reasonable
           | to be skeptical here, not just because of the AI label, but
           | especially for the troubled history of neural-network based
           | ML methods for weather prediction.
           | 
           | Even before LLMs got big, a lot of machine learning research
           | being published were models which underperformed SOTA (which
           | was the case for weather modeling for a long time!) or models
           | which are far far larger than they need to be (e.g. this [1]
           | Nature paper using 'deep learning' for aftershock prediction
           | being bested by this [2] Nature paper using one neuron.
           | 
           | [1] https://www.nature.com/articles/s41586-018-0438-y
           | 
           | [2] https://www.nature.com/articles/s41586-019-1582-8
        
             | sdenton4 wrote:
             | Not all transformers are LLMs.
        
               | lynndotpy wrote:
               | Yes, that is not in contention. Not all transformers are
               | LLMs, not all neural networks are transformers, not all
               | machine learning methods are neural networks, not all
               | statistical methods are machine learning.
               | 
               | I'm not saying this is an LLM, margalabargala is not
               | saying this is an LLM. They only said they hoped that
               | they did not integrate an LLM into the weather model,
               | which is a reasonable and informed concern to have.
               | 
               | Sigmar is correctly pointing out that they're using a
               | transformer model, and that transformers are effective
               | for modeling things other than language. (And,
               | implicitly, that this _isn't_ adding a step where they
               | ask ChatGPT to vibe check the forecast.)
        
               | brookst wrote:
               | "I hope these experts who have worked in the field for
               | years didn't do something stupid that I imagine a novice
               | would do" is a reasonable concern?
        
               | lynndotpy wrote:
               | Yes, it is a very reasonable concern.
               | 
               | The quoted NOAA Administrator, Neil Jacobs, published at
               | least one falsified report during the first Trump
               | administration to save face for Trump after he claimed
               | Hurricane Dorian would hit Alabama.
               | 
               | It's about as stupid as replacing magnetic storage tapes
               | with SSDs or HDDs, or using a commercial messaging app
               | for war communications and adding a journalist to it.
               | 
               | It's about as stupid as using .unwrap() in production
               | software impacting billions, or releasing a buggy and
               | poorly-performing UX overhaul, or deploying a kernel-
               | level antivirus update to every endpoint at once without
               | a rolling release.
               | 
               | But especially, it's about as stupid as putting a
               | language model into a keyboard, or an LLM in place of
               | search results, or an LLM to mediate deals and sales in a
               | storefront, or an LLM in a $700 box that is supported for
               | less than a year.
               | 
               | Sometimes, people make stupid decisions even when they
               | have fancy titles, and we've seen myriad LLMs inserted
               | where they don't belong. Some of these people make
               | intentionally malicious decisions.
        
         | Legend2440 wrote:
         | It's not an LLM, but it is genAI. It's based on the same idea
         | of predict-the-next-thing, but instead of predicting words it
         | predicts the next state of the atmosphere from the current
         | state.
        
           | adamweld wrote:
           | It is in fact one of the least generalized forms of "AI" out
           | there. A model focused solely on predicting weather.
        
             | astrange wrote:
             | "gen" stands for "generative". If you read the GenCast
             | paper they call it a generative AI - IIRC it's an
             | autoregressive GNN plus a diffusion model.
             | 
             | Which is surprising to me because I didn't think it would
             | work for this; they're bad at estimating uncertainty for
             | instance.
        
               | Majromax wrote:
               | > Which is surprising to me because I didn't think it
               | would work for this; they're bad at estimating
               | uncertainty for instance.
               | 
               | FGN (the model that is 'WeatherNext 2'), FourCastNet 3
               | (NVIDIA's offering), and AIFS-CRPS (the model from ECMWF)
               | have all moved to train on whole ensembles, using a
               | cumulative ranked probability score (CRPS) loss function.
               | Minimizing the CRPS minimizes the integrated square
               | differences of the cumulative density function between
               | the prediction and truth, so it's effectively teaching
               | the model to have uncertainty proportional to its
               | expected error.
               | 
               | GenCast is a more classic diffusion-based model trained
               | on a mean-squared-error-type loss function, much like any
               | of the image diffusion models. Nonetheless it performed
               | well.
        
         | lukeschlather wrote:
         | The GraphCast paper says "GraphCast is implemented using GNNs"
         | without explaining that the acronym stands for Graph Neural
         | Networks. It contrasts GNNs to the " convolutional neural
         | network (CNN)" and "graph attention network." (GAN?) It doesn't
         | really explain the difference between GAN and a GNN. I think
         | LLMs are GANs. So no, it's not an LLM in a weather model, but
         | it's very similar to an LLM in terms of how it is trained.
        
           | astrange wrote:
           | > I think LLMs are GANs.
           | 
           | They aren't, but both of them are transformer models.
           | 
           | nb GAN usually means something else (Generative Adversarial
           | Network).
        
             | lukeschlather wrote:
             | I used GAN to mean graph attention network in my comment,
             | which is how the GraphCast paper defines transformers.
             | https://arxiv.org/pdf/2212.12794
             | 
             | I was looking at this part in particular:
             | 
             | > And while Transformers [48] can also compute arbitrarily
             | long-range computations, they do not scale well with very
             | large inputs (e.g., the 1 million-plus grid points in
             | GraphCast's global inputs) because of the quadratic memory
             | complexity induced by computing all-to-all interactions.
             | Contemporary extensions of Transformers often sparsify
             | possible interactions to reduce the complexity, which in
             | effect makes them analogous to GNNs (e.g., graph attention
             | networks [49]).
             | 
             | Which kind of makes a soup of the whole thing and suggests
             | that LLMs/Graph Attention Networks are "extensions to
             | transformers" and not exactly transformers themselves.
        
               | astrange wrote:
               | Oh yeah, GNN (graph neural network) is the common term,
               | "graph attention network" is pretty confusing because a
               | GAN is a totally different architecture.
               | 
               | (Well, not necessarily architecture. Training method?)
        
         | optimalsolver wrote:
         | You're absolutely right! That _was_ a category 5. Thanks for
         | pointing that out.
        
       | Workaccount2 wrote:
       | Interestingly, while this model is based on a Google Deepmind AI
       | weather model, it's based on a model from 2023 (GraphCast) rather
       | than the WeatherNext 2 model which has grabbed headlines as of
       | late. I'd imagine it takes a while to integrate and test
       | everything, explaining the gap.
        
         | sigmar wrote:
         | I've been assuming that, unlike graphcast, they have no
         | intention to make weathernext 2 open source.
        
           | tndl wrote:
           | That seems to be the case from what I've heard.
        
         | Majromax wrote:
         | Google Research and Google DeepMind also build their models for
         | Google's own TPU hardware. It's only natural for them, but
         | weather centres can't buy TPUs and can't / don't want to be
         | locked to Google's cloud offerings.
         | 
         | For Gencast ('WeatherNext Gen', I believe), the repository
         | provides instructions and caveats (https://github.com/google-
         | deepmind/graphcast/blob/main/docs/...) for inference on GPU,
         | and it's generally slower and more memory intensive. I imagine
         | that FGN/WeatherNext 2 would also have similar surprises.
         | 
         | Training is also harder. DeepMind has only open-sourced the
         | inference code for its first two models, and getting a working,
         | reasonably-performant training loop written is not trivial.
         | NOAA hasn't retrained its weights from scratch, but the fine-
         | tuning they did re: GFS inputs still requires the full training
         | apparatus.
        
       | username223 wrote:
       | Whatever it is, it seems like it might be roughly competitive
       | with ECMWF, the state of the art when it comes to global weather
       | models: https://www.epic.noaa.gov/ai/eagle-verification/
       | 
       | A quick search didn't turn up anything about the model's skill or
       | resolution, though I'm sure the data exists.
        
         | ryuuchin wrote:
         | They run at 0.25 degree resolution (same as ECMWF AIFS models).
        
       | apawloski wrote:
       | I've seen the Microsoft Aurora team make a compelling argument
       | that weather is an interesting contradiction of the AI-energy-
       | waste narrative. Once deployed at scale, inference with these
       | models is actually a sizable energy/compute _improvement_ over
       | classical simulation and forecasting methods. Of course it is
       | energy intensive to train the model, but the usage itself is more
       | energy efficient.
        
         | klysm wrote:
         | It's definitely interesting that some neural nets can reduce
         | compute requirements, but that's certainly not making a dent on
         | the LLM part of the pie.
        
           | lukeschlather wrote:
           | Sam Altman has made a lot of grandiose claims about how much
           | power he's going to need to scale LLMs, but the evidence
           | seems to suggest the amount of power required to train and
           | operate LLMs is a lot more modest than he would have you
           | believe. (DeepSeek reportedly being trained for just $5M, for
           | example.)
        
             | lovich wrote:
             | I saw a claim that DeepSeek had piggybacked off of some
             | aspect of training that ChatGPT had done, and so that cost
             | needed to be included when evaluating DeepSeek.
             | 
             | This training part of LLMs is still mostly Greek to me, so
             | if anyone could explain that claim as true or false and the
             | reasons why, I'd appreciate it
        
               | TomatoCo wrote:
               | So LLMs predict the next token. Basically, you train them
               | by taking your training data that's N words long and, for
               | X = 1 to N, and optimizing it to predict token X using
               | tokens 1 to X-1.
               | 
               | There's no reason you couldn't generate training data for
               | a model by getting output from another model. You could
               | even get the probability distribution of output tokens
               | from the source model and train the target model to
               | repeat that probability distribution, instead of a single
               | word. That'd be faster, because instead of it learning to
               | say "Hello!" and "Hi!" from two different examples, one
               | where it says hello and one where it says hi, you'd learn
               | to say both from one example that has a probability
               | distribution of 50% for each output.
               | 
               | Sometimes DeepSeek said it's name is ChatGPT. This could
               | be because they used Q&A pairs from ChatGPT for training
               | or because they scraped conversations other people posted
               | where they were talking to ChatGPT. Or for unknown
               | reasons where the model just decided to respond that way,
               | like mixing up some semantics of wanting to say "I'm an
               | AI" and all the scraped data referring to AI as ChatGPT.
               | 
               | Short of admission or leaks of DeepSeek training data
               | it's hard to tell. Conversely, DeepSeek really went hard
               | into an architecture that is cheap to train, using a lot
               | of weird techniques to optimize their training process
               | for their hardware.
               | 
               | Personally, I think they did. Research shows that a model
               | can be greatly improved with a relatively-small set of
               | high quality Q&A pairs. But I'm not sure the cost
               | evaluation should be influenced that much, because the
               | ChatGPT training price was only paid once, it doesn't
               | have to be repaid for every new model that cribs its
               | answers.
        
               | lukeschlather wrote:
               | I think the claim that DeepSeek was trained for $5M is a
               | little questionable. But OpenAI is trying to raise $100B
               | which is 20,000 times as much as $5M. Though even at $1B
               | I think it's probably not that big a deal for Google or
               | OpenAI. My feeling is they can profit on the prices they
               | are charging for their LLM APIs, and that the dominant
               | compute cost is inference, not training. Though obviously
               | that's only true if you're selling billions of dollars
               | worth of API calls like Google and OpenAI.
               | 
               | OpenAI has had $20B in revenue this year, and it seems
               | likely to me they have spent considerably less than that
               | on compute for training GPT5. Probably not $5M, but quite
               | possibly under $1B.
        
         | throwaway613745 wrote:
         | "it's more efficient if you ignore the part where it's not"
        
           | TallGuyShort wrote:
           | It's more efficient anyway because the inference is what
           | everyone will use for forecasting. Researchers will be using
           | huge amounts of compute to develop better models, but that's
           | also currently the case, and it isn't the majority of weather
           | simulation use.
           | 
           | There's an interesting parallel to Formula One, where there
           | are limits on the computational resources teams can use to
           | design their cars, and where they can use an aerodynamic
           | model that was previously trained to get pretty good outcomes
           | with less compute use in the actual design phase.
        
           | apawloski wrote:
           | I mean that's cute, but surely you can add up the two parts
           | (single training plus globally distributed inference) and
           | understand that the net efficiency would be an improvement?
        
           | Majromax wrote:
           | > "it's more efficient if you ignore the part where it's not"
           | 
           | Even when you include training, the payoff period is not that
           | long. Operational NWP is enormously expensive because high-
           | resolution models run under soft real-time deadlines; having
           | today's forecast tomorrow won't do you any good.
           | 
           | The bigger problem is that traditional models have decades of
           | legacy behind them, and getting them to work on GPUs is
           | nontrivial. That means that in a real way, AI model training
           | and inference comes at the expense of traditional-NWP
           | systems, and weather centres globally are having to strike
           | new balances without a lot of certainty.
        
           | brookst wrote:
           | I suggest reading up on fixed costs vs variable costs and why
           | it is generally preferable to push costs to fixed.
           | 
           | Assuming you're not throwing the whole thing out after one
           | forecast, it is probably better to reduce runtime energy
           | usage even if it means using more for one-time training.
        
         | threemux wrote:
         | This jumped out at me as well - very interesting that it
         | actually reduces necessary compute in this instance
        
           | derbOac wrote:
           | The press statement is full of stuff like this:
           | 
           | "Area for future improvement: developers continue to improve
           | the ensemble's ability to create a range of forecast
           | outcomes."
           | 
           | Someone else noted the models are fairly simple.
           | 
           | My question is "what happens if you scale up to attain the
           | same levels of accuracy throughout? Will it still be as
           | efficient?"
           | 
           | My reading is that these models work well in other regions
           | but I reserve a certain skepticism because I think it's
           | healthy in science, and also because I think those ultimately
           | in charge have yet to prove reliable judges of anything
           | scientific.
        
             | Majromax wrote:
             | > My question is "what happens if you scale up to attain
             | the same levels of accuracy throughout? Will it still be as
             | efficient?"
             | 
             | I've done some work in this area, and the answer is
             | probably 'more efficient, but not quite as spectacularly
             | efficient.'
             | 
             | In a crude, back-of-the-envelope sense, AI-NWP models run
             | about three orders of magnitude faster than notionally
             | equivalent physics based NWP models. Those three orders of
             | magnitude divide approximately evenly between three
             | factors:
             | 
             | 1. AI-NWP models produce much sparser outputs compared to
             | physics-based models. That means fewer variables and
             | levels, but also coarser timesteps. If a model needs to run
             | 10x as often to produce an output every 30m rather than
             | every 6h, that's an order of magnitude right there.
             | 
             | 2. AI-NWP models are "GPU native," while physics-based
             | models emphatically aren't. Hypothetically running physics-
             | based models on GPUs would gain most of an order of
             | magnitude back.
             | 
             | 3. AI-NWP models have fantastic levels of numerical
             | intensity compared to physics-based NWP models since the
             | former are "matrix-matrix multiplications all the way
             | down." Traditional NWP models perform relatively little
             | work per grid point in comparison, which puts them on the
             | wrong (badly memory-bandwidth limited) side of the roofline
             | plots.
             | 
             | I'd expect a full-throated AI-NWP model to give up most of
             | the gains from #1 (to have dense outputs), and dedicated
             | work on physics-based NWP might close the gap on #2.
             | However, that last point seems much more durable to me.
        
         | AStrangeMorrow wrote:
         | Obviously much simpler Neural Nets, but we did have some models
         | in my domain whose role was to speed up design evaluation.
         | 
         | Eg you want to find a really good design. Designs are fairly
         | easy to generate, but expensive to evaluate and score.
         | Understand we can quickly generate millions of designs but
         | evaluating one can take 100ms-1s. With simulations that are not
         | easy to GPU parallelize. We ended up training models that try
         | to predict said score. They don't predict things perfectly, but
         | you can be 99% sure that the actual score designs is within a
         | certain distance of said score.
         | 
         | So if normally you want to get the 10 best design out of your 1
         | million, we can now first have the model predict the best 1000
         | and you can be reasonably certain your top 10 is a subset of
         | these 1000. So you only need to run your simulation on these
         | 1000.
        
           | trillic wrote:
           | Heuristical branch-and-bound
        
         | esafak wrote:
         | And an LLM can be more energy efficient than a human -- and
         | that's precisely when you should use it.
        
           | brewtide wrote:
           | That's precisely when, (insert hand wavy motion), we should
           | use any of this.
        
           | xphos wrote:
           | If its more energy efficient it is doing something different
           | there is no guarantee that its more accurate long term.
           | Weather is horrible difficult to predict and we are only just
           | alright at it. If LLM are guessing at the same rate we are
           | calculating but I am doubtful
        
             | xphos wrote:
             | Well that was a failed response opps. I am just cautious
             | because while transformers get the random guessing right
             | you can get the right answer statistically but fail on
             | accuracy improvement long term. Clearly this model does
             | better than the current model but extending it to be even
             | better seems basically intractable besides throw more data
             | at it but what if it derived the wrong model you simply
             | cannot actually know
        
         | gwern wrote:
         | There's also the efficiency argument from new capability: even
         | a tiny bit better weather forecast is highly economically
         | valuable (and saves a lot of wasted energy) if it means that 1
         | city doesn't have to evacuate because of an erroneous hurricane
         | forecast, say. But how much would it cost to do that with the
         | rivals? I don't know but I would guess quite a lot.
         | 
         | And one of the biggest ironies of AI scaling is that where
         | scaling succeeds the most in improving efficiency, we realize
         | it the least, because we don't even think of it as an option.
         | An example: a Transformer (or RNN) is not the only way to
         | predict text. We have scaling laws for n-grams and text
         | perplexity (most famously, from Jeff Dean et al at Google back
         | in the 2000s), so you can actually ask the question, 'how much
         | would I have to scale up n-grams to achieve the necessary
         | perplexity for a useful code writer competitive with Claude
         | Code, say?' This is a perfectly reasonable, well-defined
         | question, as high-order n-grams could in theory write code
         | without enough data and big enough lookup tables, and so it can
         | be answered. The answer will look something like 'if we turned
         | the whole earth into computronium, it still wouldn't be
         | remotely enough'. The efficiency ratio is not 10:1 or 100:1 but
         | closer to [?]:1. The efficiency gain is _so_ big no one even
         | thinks of it as an efficiency gain, because you just couldn 't
         | do it before using AI! You would have humans do it, or not do
         | it at all.
        
           | kingkawn wrote:
           | Now that we've saved infinite energy all carbon tax credit
           | markets are unnecessary! Big win for the climate! _pollutes_
        
           | hammock wrote:
           | > even a tiny bit better weather forecast is highly
           | economically valuable (and saves a lot of wasted energy) if
           | it means that 1 city doesn't have to evacuate because of an
           | erroneous hurricane forecast
           | 
           | Here is the NOAA on the improvements:
           | 
           | > 8% better predictions for track, and 10% better predictions
           | for intensity, especially at longer forecast lead times --
           | with overall improvements of four to five days.(1)
           | 
           | I'd love someone to explain what these measurements mean
           | though. Does better track mean 8% narrower angle? Something
           | else? Compared to what baseline?
           | 
           | And am I reading this right that that improvement is measured
           | at the point 4-5 days out from landfall? What's the typical
           | lead time for calling an evacuation, more or less than four
           | days?
           | 
           | (1)https://www.noaa.gov/news/new-noaa-system-ushers-in-next-
           | gen...
        
           | inciampati wrote:
           | To have a competitive code writer with ngrams you need more
           | than to "scale up the ngrams" you need to have a corpus that
           | includes all possible codes that someone would want to write.
           | And at that point you'd be better off with a lossless full
           | text index like an r-index. But, the lack of any
           | generalizability in this approach, coupled with its markovian
           | features, will make this kind of model extremely brittle.
           | Although, it would be efficient. You just need to somehow
           | compute all possible language before hand. tldr; language
           | models really are reasoning and generalizing over the domain
           | they're trained on.
        
       | ryuuchin wrote:
       | These are available on Weatherbell[1] (which requires a
       | subscription) now except for the HGEFS ensemble model which I'm
       | guessing will probably be added later. AIGFS is on tropical
       | tidbits which should be free for some stuff[5]. I believe some of
       | the research on this is mentioned in these two[2][3] videos from
       | NOAA weather partners site. They also talk about some of the
       | other advances in weather model research.
       | 
       | One of the big benefits of both the single run (AIGFS) and
       | ensemble (AIGEFS) models is the speed and (less) computation time
       | required. Weather modeling is hard and these models should be
       | used as complementary to deterministic models as they all have
       | their own strengths and weaknesses. They run at the same 0.25
       | degree resolution as the ECMWF AIFS models which were introduced
       | earlier this year and have been successful[4].
       | 
       | Edit: Spring 2025 forecasting experiment results is available
       | here[6].
       | 
       | [1] https://www.weatherbell.com/
       | 
       | [2] https://www.youtube.com/watch?v=47HDk2BQMjU
       | 
       | [3] https://www.youtube.com/watch?v=DCQBgU0pPME
       | 
       | [4] https://www.ecmwf.int/en/forecasts/dataset/aifs-machine-
       | lear...
       | 
       | [5] https://www.tropicaltidbits.com/analysis/models/
       | 
       | [6]
       | https://repository.library.noaa.gov/view/noaa/71354/noaa_713...
        
         | tndl wrote:
         | Really exciting to see NOAA finally make some progress on this
         | front, but the AIGFS suite likely won't outperform ECMWF's AIFS
         | suite any time soon. The underlying architecture between AIFS
         | and GraphCast/AIGFS is pretty similar (both GNNs), so there
         | won't likely be a model-level improvement. And most of ECMWF's
         | edge lies in its superior 4DVar data assimilation process.
         | AIGFS is still being initialized on NOAA's hybrid 4DEnVar
         | assimilation process as far as I understand it, which is still
         | not as good as straight up 4DVar unfortunately.
        
           | kkylin wrote:
           | Came here to say this -- looks like the data assimilation is
           | still done the "old fashioned" way. I wonder how long that
           | will last?
        
             | Frostlike1417 wrote:
             | There are multiple efforts and a good number of VC working
             | on AI DA system. DA is fundamentally a hand-crafted
             | optimization process just like NN. I once reimplemented an
             | EnKF in pytorch and it works amazingly fast. But our
             | observations are so dirty and sparse. ECMWF tuned their
             | system so well. NOAA definitely has potential being even
             | better, but no hope any soon future IMHO.
        
       | padjo wrote:
       | What does AI refer to here? Presumably weather models have been
       | using all sorts of advanced machine learning for decades now, so
       | what's AI about this that wasn't AI previously?
        
         | tomww wrote:
         | They're using a graph neural network. From the article - "The
         | team leveraged Google DeepMind's GraphCast model as an initial
         | foundation and fine-tuned the model using NOAA's own Global
         | Data Assimilation System analyses".
         | 
         | > so what's AI about this that wasn't AI previously?
         | 
         | The weather models used today are physics-based numerical
         | models. The machine learning models from DeepMind, ECMWF,
         | Huawei and others are a big shift from the standard, numerical
         | approach used for the last decades.
        
           | padjo wrote:
           | Thanks, I guess my assumption that ML was widely used in
           | forecasting is wrong.
           | 
           | So are they essentially training a neural net on a bunch of
           | weather data and getting a black box model that is expensive
           | to train but comparatively cheap to run?
           | 
           | Are there any other benefits? Like is there a reason to
           | believe it could be more accurate than a physics model with
           | some error bars?
        
             | Majromax wrote:
             | > Are there any other benefits? Like is there a reason to
             | believe it could be more accurate than a physics model with
             | some error bars?
             | 
             | Surprisingly, the leading AI-NWP forecasts are more
             | accurate than their traditional counterparts, even at large
             | scales and long lead times (i.e. the 5-day forecast).
             | 
             | The reason for this is not at all obvious, to the point I'd
             | call it an open question in the literature. Large-scale
             | atmospheric dynamics are a well-studied domain, so physics-
             | based models essentially have to be getting "the big stuff"
             | right. It's reasonable to think that AI-NWP models are
             | doing a better job at sub-grid parameterizations and local
             | forcings because those are the 'gaps' in traditional NWP,
             | but going from "improved modelling of turbulence over urban
             | and forest areas" (as a hypothetical example) to
             | "improvements in 10,000 km-scale atmospheric circulation 5
             | days later" isn't as certain.
        
             | counters wrote:
             | Machine learning _has_ been widely used in weather
             | forecasting, but in a different way than these models.
             | Going back to the 1970's, you never just take the output of
             | a numerical weather model and call it a forecast. We know
             | that limitations in the models' resolution and
             | representation of physical processes lead to huge biases
             | and missed details that cause the forecast to disagree with
             | real world observations. So a standard technique has been
             | to post-process model outputs, calibrating them for station
             | observations where available. You don't need super complex
             | ML to really dramatically improve the quality or skill of
             | the forecast in this manner; typically multiple linear
             | regressions with some degree of feature selection and other
             | criteria will capture most of the variance, especially when
             | you pool observation stations together.
        
           | bee_rider wrote:
           | Do these ML models replace the numerical approach completely?
           | A lot of numerical methods are iterative. If the ML model can
           | produce a good initial guess, it might make convergence of an
           | iterative process quite a bit quicker...
        
             | NetMageSCW wrote:
             | Reading the article could have helped with this.
        
         | carabiner wrote:
         | > Presumably weather models have been using all sorts of
         | advanced machine learning for decades now
         | 
         | This isn't actually true, unless you're considering ML to be
         | just linear regression, in which case we have been using "AI"
         | for >100 years. "Advanced ML" with NN is what's being showcased
         | here.
        
         | curt15 wrote:
         | AI refers to whatever would have been called "Machine Learning"
         | five years ago.
        
         | minimaxir wrote:
         | This ambiguity resulted in some very funny drama on Bluesky:
         | https://bsky.app/profile/nws.noaa.gov/post/3ma754dbtuj2t
        
           | carabiner wrote:
           | Holy shit lmao. Like the wokest tumblr crowd focused into a
           | laser for 2025. How do these guys get through life?
           | Exhausting existence.
        
       | CalChris wrote:
       | Neil Jacobs, Ph.D
       | 
       | This makes me skeptical that it isn't just politicized Trumpian
       | nonsense.
        
       | luc_ wrote:
       | I wonder if the new models consider land use change and emissions
       | from aggressive datacenter development and model training...
        
       | adamredwoods wrote:
       | Is there a primer for reading these files?
       | 
       | https://www.nco.ncep.noaa.gov/pmb/products/gens/
       | 
       | https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_s...
        
         | jasonmarks_ wrote:
         | No, not really. If you are just looking to work with the data
         | you want to read about extracting from grib2 format. One of the
         | faster ways off the ground is to use the Pywgrib2_s python
         | package and iterate against the model files using python to
         | extract the fields that are interesting. I have a container on
         | docker hub that has pywgrib compiled with all its dependencies
         | if you want to tinker.
         | 
         | pywgrib
         | https://www.cpc.ncep.noaa.gov/products/people/lxu/cookbook/a...
         | containerized
         | https://hub.docker.com/repository/docker/jmarks213/container...
        
           | counters wrote:
           | It's far, far simpler for users to simply use eccodes[1],
           | particularly as implemented in xarray[2].
           | 
           | [1]: https://github.com/ecmwf/eccodes [2]:
           | https://docs.xarray.dev/en/stable/index.html
        
             | jasonmarks_ wrote:
             | That is another viable path, no more no less.
        
       | jasonmarks_ wrote:
       | These look like staging MVP releases with a full rollout planned
       | for the future. They are only including a few parameters at every
       | 6 hours which is barely interesting to anyone with their feet on
       | the ground.
        
       | DaveZale wrote:
       | how about working with Weather Underground to validate predicted
       | weather at ground level? Here in Southern CO would be a perfect
       | place to try this. Weather Underground has thousands of volunteer
       | backyard weather stations, including mine.
       | 
       | I understand that aviation safety is certainly a primary concern
       | for NWS/NOAA but ground level forecasts are also very important
       | for public safety.
        
       | cramcgrab wrote:
       | Apparently it seems to be impossible with these files and the
       | best AI right now to answer the simple question, will it rain in
       | midtown Manhattan tomorrow?
        
         | defrost wrote:
         | Take an umbrella if you're concerned.
         | 
         | What is possible is to know with near certainty the rough
         | tonnage of water that will fall across a wide area grain region
         | in an upcoming week.
         | 
         | Useful for the reliable production of grain (timing seeding,
         | harvesting, spraying, etc) in the millions of tonnes.
        
       | ryandrake wrote:
       | Protip: Any time you read "AI" in a news article, substitute the
       | phrase "faster, more numerous, and confidently incorrect." I
       | don't think we need "confidently incorrect" weather models. Who
       | is asking for this?
        
         | tndl wrote:
         | These models actually outperform traditional methods on many
         | fronts, including accuracy a lot of the time. They are
         | technically generative AI models, but they're definitely not
         | LLMs.
        
         | klysm wrote:
         | If it were LLM I'd agree, but that's not the case here.
        
       | Incipient wrote:
       | How well do these predict extremes/outliers? Given that I expect
       | these are more "ML" type models, these are somewhat limited to
       | interpolation, rather than extrapolation?
        
       | gvkhna wrote:
       | Working on AI driven weather predictions to make money on
       | prediction markets. The accuracy of WeatherNext 2 is astounding.
       | 
       | It may be a fools errand but makes for an extremely interesting
       | research project. http://climatesight.app if you're interested in
       | climate markets.
        
         | cl42 wrote:
         | Have you considered launching your own weather prediction
         | market instead?
         | 
         | Parametric insurance, energy traders, etc could be good
         | markets.
        
           | gvkhna wrote:
           | No I haven't but I think the lack of liquidity as a chicken
           | and egg is a huge barrier to entry in these markets
           | specifically. They are small right now but there are climate
           | derivatives on the Chicago mercantile exchange so this isn't
           | a new concept I think.
           | 
           | Could you tell me more? https://discord.gg/HPpN42SKQ
        
       | lisp2240 wrote:
       | All these years later and we still don't have the minute-accurate
       | forecasts that Dark Sky had before Apple shut it down. Living in
       | the future sucks.
        
         | Tempest1981 wrote:
         | My friend's kids would ride their bikes to school in the
         | morning, and on rainy days, check Dark Sky to find the driest
         | time window. It was usually quite accurate.
        
         | vitorgrs wrote:
         | If you mean minute-accurate forecast for the next 4-6 years...
         | That's called Nowcasting, and yes, it exists. Bing Weather have
         | it, ACCU Weather as well. Rain viewer too. I believe Google
         | already implemented on Pixel Weather at least.
         | 
         | IMO the best of these are Bing Weather and Rain Viewer, both
         | provide rich maps showing where the rain it's going and all
         | too. And how much.
        
           | lisp2240 wrote:
           | No.
        
           | axismundi wrote:
           | Did you mean 4-6 hours?
        
         | NetMageSCW wrote:
         | Apple definitely broke something when they incorporated Dark
         | Sky into their weather ecosystem and it isn't nearly as good in
         | my locality.
        
         | Terretta wrote:
         | Apple purports to still have this, but it is indeed less
         | reliable than Dark Sky.
         | 
         | However, the author of Carrot for iOS implemented his own
         | flavor of this* and it's remarkably decent.
         | 
         | * According to Gruber interview around the same time Carrot
         | introduced an entire Broadway musical about the conflict
         | between the Carrot AI and her Maker (the dev). Which, while
         | made with AI, is rather more listenable than the typical
         | weather app.
        
       | matt3210 wrote:
       | Does ai mean LLM here or just normal software?
        
       | jmclnx wrote:
       | Where I am the last couple of years, the EU model out performed
       | the US model. The local stations tend to show both when sever
       | weather is on its way to the area.
       | 
       | We know how the current admin views science and with the cuts to
       | NOAA done this year, I expect that trend to continue and widen.
       | At least where I am, we get to see both.
        
       | JoeDaDude wrote:
       | I know someone pursuing a degree in meteorology at well known
       | university for the subject and I asked that person if they are
       | being taught about these and other AI weather models, about how
       | they work, how to evaluate them for effectiveness, etc.
       | 
       | The answer: AI is not even covered, at least at the undergrad
       | level. This is just a sample of one, so are any other
       | universities educating future meteorologists on this subject?
        
         | NetMageSCW wrote:
         | Are meteorologists even the right people to be training on how
         | to produce and improve better modeling of weather?
        
       | tylervigen wrote:
       | This is big news. For decades, NOAA's model has basically just
       | been a huge Fortran physics simulation. Now they are making the
       | leap to AI.
       | 
       | I suspect the nail in the coffin was the hurricane season, where
       | NOAA's model was basically beat by every major AI model. [0]
       | 
       | The GFS also just had its worst year in predicting hurricane
       | paths since 2005. [1] That's not a trend you want to continue.
       | 
       | [0] https://arstechnica.com/science/2025/11/googles-new-
       | weather-...
       | 
       | [1] https://www.local10.com/weather/hurricane/2025/11/03/this-
       | hu...
        
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